Skip directly to search Skip directly to A to Z list Skip directly to site content

PETITIONED HEALTH CONSULTATION

CADY ROAD
NORTH ROYALTON, CUYAHOGA COUNTY, OHIO


APPENDIX D: AIR AND WATER SAMPLING DATA

Table 1. VOCs in Air -- Sampling Results1

  Indoor Air2 Outdoor Air Grab sample from wellhead3
  Frequency detected Range of detected results (ppb) Frequency detected Range of detected results (ppb) Result (ppb)
Dichlorofluoromethane 9/9 0.38 – 10.00 3/3 0.39 – 0.46 ND
Chloromethane 8/9 0.53 – 1.20 3/3 0.62 – 0.75 ND
Freon-11 8/9 0.28 – 5.70 1/3 0.34 ND
Carbon disulfide 6/9 0.40 – 1.90 2/3 0.47 – 0.57 ND
Acetone 8/9 1.20 – 120.00 3/3 3.10 – 4.80 ND
Methylene chloride 8/9 0.26 – 8.50 2/3 2.10 – 3.00 ND
2-Butanone 8/9 0.79 – 4.00 3/3 0.46 – 3.90 ND
Chloroform 1/9 0.36 0/3 ND ND
Carbon tetrachloride 1/9 0.32 0/3 ND ND
1,1,1-Trichloroethane 3/9 0.35 – 2.10 0/3 ND ND
Benzene 9/9 0.49 – 5.60 3/3 0.22 – 0.70 0.20
Trichloroethene 1/9 0.38 0/3 ND ND
Toluene 9/9 1.70– 36.00 3/3 0.34 – 11.00 1.30
Tetrachloroethene 1/9 0.35 0/3 ND ND
Ethylbenzene 8/9 0.30 – 2.30 1/3 1.10 1.10
m,p-Xylene 8/9 0.86 – 8.80 1/3 3.30 0.61
o-Xylene 8/9 0.33 – 3.40 1/3 0.93 0.39
Styrene 7/9 0.28 – 3.90 1/3 0.50 ND
4-Ethyltoluene 5/9 0.32 – 2.50 0/3 ND ND
1,3,5-Trimethylbenzene 4/9 0.34 – 2.60 0/3 ND 0.39
1,2,4-Trimethylbenzene 7/9 0.32 – 5.10 0/3 ND 0.50
Methane 8/9 13,000 – 60,000 ppb or 13 – 60 ppm 0/3 ND 260,000,000 ppb or 260,000 ppm
Ethane 2/9 3,600 – 18,000 0/3 ND 21,000,000
Propane 2/9 2,100 – 21,000 0/3 ND 11,000,000
Butane 2/9 460 – 9, 200 0/3 ND 2,000,000
Pentane 1/9 900 0/3 ND 130,000
Hexane 1/9 1,200 0/3 ND 20,000

1 The table includes only detected chemicals. For a full list of VOC analytes, see appendix E.
2 Tentatively Identified Compounds (TICs) in indoor air include: chlorodifluoromethane, dimethyl ether, propane, propene, isobutene, butane, 2-methylbutane, ethanol, Freon-141, isopropyl alcohol, pentane, 2-methylpentane, 3-methylpentane, methylcyclopentane, 2,3-dimethylpentane, 3-methylhexane, 2,2,4-trimethylpentane, heptane, hexanal, nonane, dimethyldisulfide, 2,6-dimethyloctane, alpha-pinene, limonene, decane, and undecane.
3 Tentatively Identified Compounds (TICs) in the grab wellhead sample include: propane, propene, isobutene, 2-methylbutane, and 2-methylpentane.


Table 2. Water Sampling Results

  Frequency detected Range of detected results (ppb)
VOCs1
Acetone 3/9 3.0 – 6.8
Methylene Chloride 3/9 0.20 – 0.23
Toluene 1/9 0.56
Metals
Aluminum 4/9 28 – 1,700
Barium 9/9 17 – 160
Calcium 9/9 3,200 – 7,700
Chromium 2/9 2.7 – 6.5
Copper 5/9 8.9 – 37
Iron 9/9 66 – 12,000
Lead 1/9 20
Magnesium 9/9 1,700 – 3,200
Manganese 9/9 7 – 60
Molybdenum 6/9 21 – 24
Potassium 9/9 1,300 – 2,900
Sodium 9/9 160,000 – 330,000
Zinc 9/9 3.5 - 560
Inorganic Ions
Bromide 9/9 510 – 790
Chloride 9/9 94,000 – 160,000
Fluoride 9/9 1,400 – 1,800
Nitrate 2/9 5.8 – 8.1
Sulfate 5/9 130 – 44,000
Sulfide 2/9 1,800 – 4,180
Dissolved Gases
Methane 9/9 1,100 – 11,000
Ethane 3/9 13 – 1,600
Ethene 1/9 310

1 Tentatively Identified Compounds (TICs) include: propane, isobutane, butane, 2-methylbutane, and pentane


APPENDIX E: LIST OF ANALYTES FOR AIR AND WATER SAMPLING

List of VOC analytes in water

1,1,1,2-Tetrachloroethane
1,1,1-Trichloroethane
1,1,2,2-Tetrachloroethane
1,1,2-Trichloroethane
1,1-Dichloroethane
1,1-Dichloroethene
1,2,3-Trichloropropane
1,2-Dibromo-3-chloropropane
1,2-Dibromoethane
1,2-Dichloroethane
1,2-Dichloropropane
1,3-Dichloropropane
2-Butanone
2-Hexanone
4-Methyl-2-Pentanone
Acetone
Benzene
Bromoform
Bromodichloromethane
Bromomethane
Carbon disulfide
Carbon tetrachloride
Chlorobenzene
Chloroethane
Chloroform
Chloromethane
cis-1,2-Dichloroethene
cis-1,3-Dichloropropene
Dibromochloromethane
Dibromomethane
Dichlorodifluoromethane
Ethylbenzene
Methyl-t-butyl ether
Methylene chloride
m,p-Xylenes
o-Xylene
Styrene (Ethenylbenzene)
Tetrachloroethene
Toluene
trans-1,2-Dichloroethene
trans-1,3-Dichloro-1-propene
Trichloroethene
Trichlorofluoromethane
Vinyl chloride

List of SVOC analytes in water

1,2,4-Trichlorobenzene
1,2-Dichlorobenzene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
2,4,5-Trichlorophenol
2,4,6-Trichlorophenol
2,4-Dichlorophenol
2,4-Dimethylphenol
2,4-Dinitrophenol
2,4-Dinitrotoluene
2,6-Dinitrotoluene
2-Chloronaphthalene
2-Chlorophenol
2-Chlorophenol
2-Methylnaphthalene
2-Methylphenol
2-Nitroaniline
2-Nitrophenol
3,3'-Dichlorobenzidine
3-Nitroaniline
4,6-Dinitro-2-methylphenol
4-Bromophenyl phenyl ether
4-Chloro-3-methylphenol
4-Chloroaniline
4-Chlorophenyl phenyl ether
4-Methylphenol
4-Nitroaniline
4-Nitrophenol
Acenaphthene
Acenaphthylene
Anthracene
Benz(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene.
Benzo(k)fluoranthene
Benzoic acid
Benzyl alcohol
Bis(2-chloroethoxy)methane
Bis(2-chloroethyl)ether
Bis(2-chloroisopropyl)ether
Bis(2-ethylhexyl) phthalate
Butyl benzyl phthalate
Carbazole
Chrysene
Dibenz(a,h)anthracene
Dibenzofuran
Diethyl phthalate
Dimethyl phthalate
Di-n-butyl phthalate
Di-n-octyl phthalate
Fluoranthene
Fluorene
Hexachlorobenzene
Hexachlorobutadiene
Hexachlorocyclopentadiene
Hexachloroethane
Indeno(1,2,3-sd)pyrene
Isophorone
Naphthalene
Nitrobenzene
Nitrofen
N-Nitrosodi-n-propylamine
N-Nitrosodiphenylamine
Pentachlorophenol
Phenanthrene
Phenol
Pyrene
Pyridine

List of metal analytes in water

Aluminum
Antimony
Arsenic
Barium
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Potassium
Selenium
Silver
Sodium
Thallium
Vanadium
Zinc


List of inorganic ion analytes in water

Bromide
Chloride
Fluoride
Nitrate-N
Nitrite-N
Phosphate-P
Sulfate

List of dissolved gases in water

Methane
Ethane
Ethene

List of VOC analytes in Air

1,1,1-Trichloroethane
1,1,2,2-Tetrachloroethane
1,1,2-Trichloroethane
1,1-Dichloroethane
1,1-Dichloroethene
1,2,4-Trimethylbenzene
1,2,4-Trichlorobenzene
1,2-Dibromoethane
1,2-Dichloroethane
1,2-Dichloropropane
1,2-Dichlorobenzene
1,3-Dichlorobenzene
1,4-Dichlorobenzene
1,3,5-Trimethylbenzene
2-Butanone
2-Hexanone
4-Ethyl toluene
4-Methyl-2-Pentanone
Acetone
Benzene
Benzyl chloride
Bromoform
Bromomethane
Bromodichloromethane
Carbon disulfide
Carbon tetrachloride
Chlorobenzene
Chloromethane
Chloroform
Chloroethane
cis-1,2-Dichloroethene
cis-1,3-Dichloropropene
Dibromochloromethane
Dichlorodifluoromethane
Ethylbenzene
Freon 11
Freon 113
Freon 114
Hexachlorobutadiene
Methyl-t-butyl ether
Methylene chloride
m,p-Xylenes
o-Xylene
Styrene (Ethenylbenzene)
Tetrachloroethene
Toluene
trans-1,2-Dichloroethene
trans-1,3-Dichloro-1-propene
Trichloroethene
Vinyl acetate



APPENDIX F: WATER QUALITY AND METALS

Metals in Water

Aluminum - there is no recommended daily intake for aluminum. By drinking 2 liters of private well water per day, Cady Road residents would consume from under 1 mg to 3 mg of aluminum per day. In comparison, one antacid tablet can contain as much as 200 mg of aluminum. ATSDR compared the levels of aluminum to health guidance values and found that the detected concentrations were below levels that would result in adverse health effects. The secondary standard for aluminum is set because levels above that standard may cause colored water.

Iron - the FDA's adult recommended daily intake for iron is 18 mg. By drinking 2 liters of private well water per day, Cady Road residents would consume about 1 mg to 2 mg of iron per day, or about 9%-of the recommended daily intake of iron. Iron is used by the body to make hemoglobin, which transports oxygen in the blood from the lungs to other areas of the body that need oxygen. It also helps increase the body's resistance to stress and disease. The additional iron that would be received by drinking water from the private wells on Cady Road is not harmful. The secondary standard for iron is set because high levels of iron may taste unpleasant (metallic taste) to some people, and may cause reddish or orange staining, and may turn water a rusty color.

Manganese - the FDA's adult recommended daily intake for manganese is 1 - 5 mg. By drinking 2 liters of private well water per day, Cady Road residents would consume about 0.01 mg to 0.1 mg of manganese per day, or about 1% - 10% of the daily value of manganese. Manganese is an antioxidant that helps produce energy for the body. However, high levels of manganese, well above FDA's recommended daily intake, in the diet may cause harmful effects. ATSDR compared the levels of manganese in the water to health guidance values and found that the detected concentrations were below levels that would result in adverse health effects. The secondary standard for manganese is set because levels that exceed the standard may cause the water to have a black to brown color, may cause black staining, and may have a bitter metallic taste.

Sodium - the FDA's adult recommended daily intake for sodium is 2400 mg. By drinking 2 liters of private well water per day, Cady Road residents would consume from 320 mg to 660 mg of sodium. The levels of sodium detected were from samples collected before any filtration or treatment systems. If residents use water softeners, the sodium level in the water will be even higher. Sodium is an essential nutrient used by the body to control blood pressure and volume. In addition, sodium helps the muscles and nerves function properly. However, too much sodium can cause high blood pressure. Cady Road residents should be aware that drinking well water with elevated sodium levels increases their sodium intake and should modify their diets accordingly. People who already have elevated blood pressure or who are on a sodium-restricted diet should avoid drinking water with elevated sodium levels. In addition, the high sodium levels present a general water quality problem due to the taste, and the tolerance of that taste will vary among the residents.

Molybdenum - the FDA's adult recommended daily intake for molybdenum is 0.075 mg. By drinking 2 liters of private well water per day, Cady Road residents would consume about 0.040 mg of molybdenum, or a little over half of the daily value. Molybdenum is a trace element that is important for several enzymes in the body. Levels of molybdenum were compared to health guidance values. The six wells that had detectable levels of molybdenum (21-24 ppb) exceeded the ATSDR comparison value for children (10 ppb). Since the level is less than normal daily intakes, and since there are uncertainty factors calculated into ATSDR's comparison values, it is highly unlikely that any health effects would result from these exposures for adults. However, residents, especially children, who drink water with elevated molybdenum levels, should be aware that it increases the dietary intake of molybdenum and should modify their diet accordingly.


APPENDIX G: PUBLIC HEALTH HAZARD CATEGORIES

CATEGORY 1 : URGENT PUBLIC HEALTH HAZARD

This category is used for sites where short-term exposures (< 1 yr) to hazardous substances or conditions could result in adverse health effects that require rapid intervention.

This determination represents a professional judgement based on critical data which ATSDR has judged sufficient to support a decision. This does not necessarily imply that the available data are complete; in some cases additional data may be required to confirm or further support the decision made.

Criteria

Evaluation of available relevant information* indicates that site-specific conditions or likely exposures have had, are having, or are likely to have in the future, an adverse impact on human health that requires immediate action or intervention. Such site-specific conditions or exposures may include the presence of serious physical or safety hazards, such as open mine shafts, poorly stored or maintained flammable/explosive substances, or medical devices which, upon rupture, could release radioactive materials.

* Such as environmental and demographic data; health outcome data; exposure data; community health concerns information; toxicologic, medical, and epidemiologic data.

ATSDR Actions

ATSDR will expeditiously issue a health advisory that includes recommendations to mitigate the health risks posed by the site. The recommendations issued in the health advisory and/or public health assessment should be consistent with the degree of hazard and temporal concerns posed by exposures to hazardous substances at the site.

Based on the degree of hazard posed by the site and the presence of sufficiently defined current, past, or future completed exposure pathways, one or more of the following public health actions can be recommended:

  • biologic indicators of exposure study
  • biomedical testing
  • case study
  • epidemiologic study
  • community health investigations
  • registries
  • site-specific surveillance
  • voluntary residents tracking system
  • cluster investigation
  • health statistics review
  • health professional education
  • community health education
  • substance-specific applied research

CATEGORY 2: PUBLIC HEALTH HAZARD

This category is used for sites that pose a public health hazard due to the existence of long-term exposures (> 1 yr) to hazardous substance or conditions that could result in adverse health effects.

This determination represents a professional judgement based on critical data which ATSDR has judged sufficient to support a decision. This does not necessarily imply that the available data are complete; in some cases additional data may be required to confirm or further support the decision made.

Criteria

Evaluation of available relevant information* suggests that, under site-specific conditions of exposure, long-term exposures to site-specific contaminants (including radionuclides) have had, are having, or are likely to have in the future, an adverse impact on human health that requires one or more public health interventions. Such site-specific exposures may include the presence of serious physical hazards, such as open mine shafts, poorly stored or maintained flammable/ explosive substances, or medical devices which, upon rupture, could release radioactive materials.

*Such as environmental and demographic data; health outcome data; exposure data; community health concerns information; toxicologic, medical, and epidemiologic data.

ATSDR Actions

ATSDR will make recommendations in the public health assessment to mitigate the health risks posed by the site. The recommendations issued in the public health assessment should be consistent with the degree of hazard and temporal concerns posed by exposures to hazardous substances at the site. Actions on the recommendations may have occurred before the actual completion of the public health assessment.

Based on the degree of hazard posed by the site and the presence of sufficiently defined current, past, or future completed exposure pathways, one or more of the following public health actions can be recommended:

  • biologic indicators of exposure study
  • biomedical testing
  • case study
  • epidemiologic study
  • community health investigations
  • registries
  • site-specific surveillance
  • voluntary residents tracking system
  • cluster investigation
  • health statistics review
  • health professional education
  • community health education
  • substance-specific applied research

CATEGORY 3: INDETERMINATE PUBLIC HEALTH HAZARD

This category is used for sites when a professional judgement on the level of health hazard cannot be made because information critical to such a decision is lacking.

Criteria

This category is used for sites in which "critical" data are insufficient with regard to extent of exposure and/or toxicologic properties at estimated exposure levels. The health assessor must determine, using professional judgement, the "criticality" of such data and the likelihood that the data can be obtained and will be obtained in a timely manner. Where some data are available, even limited data, the health assessor is encouraged to the extent possible to select other hazard categories and to support their decision with clear narrative that explains the limits of the data and the rationale for the decision.

ATSDR Actions

ATSDR will make recommendations in the public health assessment to identify the data or information needed to adequately assess the public health risks posed by the site.

Public health actions recommended in this category will depend on the hazard potential of the site, specifically as it relates to the potential for human exposure of public health concern. Actions on the recommendations may have occurred before the actual completion of the public health assessment.

If the potential for exposure is high, initial health actions aimed at determining the population with the greatest risk of exposure can be recommended. Such health actions include:

  • community health investigation
  • health statistics review
  • exposure investigation
  • cluster investigation
  • epidemiologic study
  • community concern review

If the population of concern can be determined through these or other actions, any of the remaining follow-up health activities listed under categories 1 and 2 may be recommended.

In addition, if data become available suggesting that human exposure to hazardous substances at levels of public health concern is occurring or has occurred in the past, ATSDR will reevaluate the need for any followup.

CATEGORY 4: NO APPARENT PUBLIC HEALTH HAZARD

This category is used for sites where human exposure to contaminated media may be occurring, may have occurred in the past, and/or may occur in the future, but the exposure is not expected to cause any adverse health effects.

This determination represents a professional judgement based on critical data which ATSDR considers sufficient to support a decision. This does not necessarily imply that the available data are complete, in some cases additional data may be required to confirm or further support the decision made.

Criteria

Evaluation of available relevant information* indicates that, under site-specific conditions of exposure, exposures to site-specific contaminants in the past, present, or future are not likely to result in any adverse impact on human health.

*Such as environmental and demographic data; health outcome data; exposure data; community health concerns information; toxicologic, medical, and epidemiologic data; monitoring and management plans.

ATSDR Actions

If appropriate, ATSDR will make recommendations for monitoring or other removal and/or remedial actions needed to ensure that humans are not exposed to significant concentrations of hazardous substances in the future. Actions on the recommendations may have occurred before the actual completion of the public health assessment.

The following health actions, which may be recommended in this category, are based on information indicating that no human exposure is occurring or has occurred in the past to hazardous substances at levels of public health concern. One or more of the following health actions are recommended for sites in this category:

  • community health education
  • health professional education
  • community health investigation
  • voluntary residents tracking system

However, if data become available suggesting that human exposure to hazardous substances at levels of public health concern is occurring, or has occurred in the past, ATSDR will reevaluate the need for any followup.

CATEGORY 5: NO PUBLIC HEALTH HAZARD

This category is used for sites that, because of the absence of exposure, do NOT pose a public health hazard.

Criteria

Sufficient evidence indicates that no human exposures to contaminated media have occurred, none are now occurring, and none are likely to occur in the future.

ATSDR Actions

The following health actions may be recommended in this category:

  • community health education
  • no recommendation at this time

APPENDIX H: RESPONSES TO PUBLIC COMMENTS

ATSDR issued a draft for the public comment petitioned public health consultation on August 27, 2002 for the Cady Road site. Between August 27, 2002 and October 11, 2002, the public had the opportunity to provide comments on the draft public health consultation. ATSDR received written comments and questions from the Cuyahoga County Board of Health, the Ohio Department of Health, the Ohio Department of Natural Resources, the City of North Royalton, the US EPA, and two residents. Where possible, these comments and questions are presented unchanged below. However, for the sake of clarity and brevity, some comments or questions were paraphrased or summarized, and are marked with a notation at the beginning of the sentence. The full correspondence is available upon request. Each italicized comment or question is followed by a response from ATSDR.

Cuyahoga County Board of Health

  1. Comment: Page 2, Background - Paragraph 3. This is not a correct statement because hydrogen sulfide is not a VOC.
  2. Response: "Volatile organic compounds" has been changed to "gases".

  3. Comment: Page 3, Line 1: A statement is made that ATSDR had concerns about the quality control and assurance issues for a 1998 ODNR grab sample which precluded ATSDR from using the data. The consultation does not set forth the concerns of ATSDR regarding the QA/QC issue.
  4. Response: The 1998 sampling event was indoor and outdoor air sampling completed by EPA, not ODNR. The main concerns with the grab samples are that they are not representative of a residential exposure because they measure over a period of 10-20 seconds, and the absence of a pressure gauge to ensure full evacuation of the canisters. This information was added to the document.

  5. Comment: Page 3, Private Well Water Results: Utilizing a worst case scenario does not provide true ambient data. Appendix D does not indicate an associated standard. Also, to delete testing after treatment devices does not provide a representative analysis of the potable water supply being used by the resident. All ambient air test results were reported utilizing worst case scenarios. The report does not contain comparative ambient air test results that were taken under varying conditions or taken on different dates or at different times.
  6. Response: ATSDR performed air screening in the homes before the treatment system was bypassed. However, the air samples (SUMMA canisters) and water samples were completed after the system was bypassed. The purpose of the exposure investigation was to determine if potentially hazardous chemicals were entering homes. ATSDR does not evaluate treatment systems nor were funds available to perform both before and after treatment sampling. Using the worst case scenario to assess residential exposure is protective of public health. The scenario could occur under any of the following instances: the household does not have any water treatment hooked up, the water treatment system has not been hooked up properly, the water treatment system has not been maintained properly, the water treatment system has failed, the water treatment system was bypassed purposely to wash cars, fill pools or another high-water usage activity, etc. Additionally, since residents used different treatment systems, sampling after treatment may have confounded comparison of results between the homes.

  7. Comment: Page 4, paragraph 1: It is stated that "the source of lead is unknown". The consultation does not set forth the testing procedure or protocols and does not discuss whether or not a sample or survey of solder joints in the plumbing were tested. Given the construction and age of these homes, it is probable that lead solder is a quite likely source.
  8. Response: The sampling methods can be found in Appendix B of the health consultation. ATSDR did not do a sample or survey of solder joints in the plumbing. ATSDR flushed the water for 15 to 20 minutes for each water sample collected to obtain a sample representative of the groundwater, and not what is in the pipes or well at that time. Therefore, it is unlikely that the source of lead is the pipes.

  9. Comment: Page 4, EPA's SMCL: The report does not state that these secondary contaminants can be easily removed with appropriate filtration devices and if the system(s) had been tested after the filtration equipment these metals may not have been detected.
  10. Response: Please see the section on Public Health Implications. Even though a few metals were above EPA's SMCL, they do not pose a health hazard. It is not necessary to recommend filtration if it does not pose a health hazard. However, this information was included in the paragraph that discusses metals and SMCL's for the residents' information.

  11. Comment: Page 5, Volatile Organics and Dissolved Gases, paragraph 1: This finding makes an assumption without fact that gases reported as non-detectable may have been present.
  12. Response: ATSDR explains the reasoning behind the statement in the paragraph. It is generally understood that volatile gases have a tendency to rapidly off-gas during sampling. Given the levels detected by handheld instruments, ATSDR is confident that the gases were underestimated. Also, given that ATSDR observed signs of gases in the water in all samples, it is very likely that the samples were not truly "non-detectable". They were only non-detectable by the sampling method.

  13. Comment: Page 5, Volatile Organics and Dissolved Gases, paragraph 2: Offers a conclusion that the private wells are impacted by gas and oil deposits but does not determine if the impact is by natural pathway or the oil and gas drilling operations. Previous investigations by other agencies and ATSDR have concluded it was by natural pathways.
  14. Response: The purpose of the health consultation is to determine whether gases or other substances in the water are causing a public health hazard, not whether they are naturally occurring. ATSDR did not make any conclusions regarding the origin of the gases in the current (September 2002) or previous (September 2001) health consultation. ATSDR referenced the ODNR's conclusion of naturally occurring oil and gas deposits on page 1, paragraph 2 of the document.

  15. Comment: Page 5, Indoor and Ambient Air Results: All ambient air test results were reported utilizing worst case scenarios. The report does not contain comparative ambient air test results that were taken under varying conditions or taken on different dates or at different times.
  16. Response: Air screening instruments were used under varying conditions in the home including: 1) levels upon entering the homes, prior to running the water, 2) upon turning on the water at locations of common water usage in the homes (i.e., kitchen and bathroom sinks), and 3 ) at the location where the water was collected (most often the basement) . Generally levels of explosive gases and H2S increased immediately upon turning on the water (if they were detected at that location). Therefore, the air screening results represent more than "worst case" scenarios. It was air screening during water usage which posed a hazard. Since the nature of the hazards is acute, these short term measurements during water usage are appropriate. The overnight collection of air in Summa canisters was not worst case sampling - but represented average air concentrations during normal water usage. Please also see the response to comment 3.

  17. Comment: Page 6, Air Screening Results, Paragraph 1: The consultation reports combustible gas levels at 0-9% and 0-19% of the LEL. The methane gas explosive rate is 5-15% in air. Usually methane action levels (associated with monitoring at sanitary landfills) do not occur until they achieve 25% of the LEL.
  18. Response: EPA recommends evacuation of an area when the combustible gas level reaches 25% of the LEL. For a residential scenario with no continuous monitoring, reaching 19% of the LEL is significant enough to warrant concern. ATSDR was only able to sample for one day, which represents a snapshot of the conditions at that time. It is unknown how the levels may fluctuate under different conditions and different times of the year. In addition, there is no detection system present in resident's houses that would let them know if the combustible gas levels reach an "evacuation" level.

  19. Comment: Page 6, Air Screening Results, Paragraph 2: The consultation makes an assumption that combustible gases originate with the water sources without investigating other sources. If methane is following a natural pathway through the ground it could be entering the home through basement wall cracks or through footer drains around the foundation. Other sources of hydrogen sulfide were not investigated. Hydrogen sulfide is a byproduct of biological decomposition and could be entering the home via untrapped or dry-trap plumbing fixtures, broken or missing stack vents or via an improperly functioning septic system.
  20. Response: ATSDR performed air screening during the sampling event to determine the pathway by which the residents were being exposed to the gases. Air screening was performed before any water was turned on in the house, including the basement, to specifically determine if a soil gas pathway was a concern. Zero or otherwise very low readings were obtained in all houses prior to water sampling. In comparison, levels of gases increased rapidly as soon as the water was turned on. ATSDR is able to conclude from this that the major contribution of gases in the air that we detected originated from the water. In addition, the presence of gases was found in the water samples analyzed by the laboratory. Our investigation does not rule out the presence of a soil gas pathway, but did determine that the major source of gases in homes is water.

  21. Comment: Page 7, Paragraph 1: The consultation does not report that a level of 30% methane in air is not explosive because it is too rich. The explosive level of methane is between 5-15% in air.
  22. Response: ATSDR did note in the report that the explosive level of methane is between 5-15%. ATSDR acknowledges the fact that 30% methane in air is too saturated to be explosive. However, it is still a concern from a public health perspective. This high amount also indicates a stronger potential for methane levels to mix with indoor air and potentially accumulate to explosive levels. Also, fluctuations in methane levels from varying conditions may decrease the level of methane to the explosive range at the wellhead. In addition, if there is 30% methane in the air, it is likely that there is not enough oxygen in the air to support human life (< 19.5%).

  23. Comment: Page 9, Paragraph 1: The consultation states that "The exposure investigation only captured the conditions of one day out of the year". Drawing such serious conclusions and making extreme maximum recommendations based on a one day sampling event is not realistic.
  24. Response: The purpose of the EI was to determine if potentially hazardous chemicals were entering homes. We agree the data ATSDR collected is not a complete characterization of the conditions in any one home or of the geographical extent of these conditions. This uncertainty is part of what informs us to act conservatively when interpreting these results. ATSDR conducts sampling to investigate if residents are being exposed to chemicals that could pose a public health hazard. Since the hazards observed are short acting and acute effects (i.e., explosive hazard and airborne exposure to hydrogen sulfide), chronic data and/or data representative of all conditions are not needed. Sufficient data were collected to demonstrate that explosive levels were possible, and elevated levels of hydrogen sulfide were present. ATSDR's goal and mission is to protect public health using preventive measures when possible. In this case, we feel we characterized the quality of the water and the exposure to residents sufficient enough to make conclusions and recommendations that would protect public health.

  25. Comment: Page 12, Conclusions: Conclusion 1; correlating outdoor data to a possible indoor hazard is unscientific. Conclusion 2; again all sources for hydrogen sulfide were not investigated. How can you correlate hydrogen sulfide in the water as the source of hydrogen sulfide in the air? If hydrogen sulfide in the water is a problem, you should make the simple recommendation of proper filtration and treatment.
  26. Response: Please see the response to comment 10. It was noted previously that the purpose of the consultation is not to identify the cause or source of the gases in the water, only whether or not those gases pose a public health hazard.

  27. Comment: [Paraphrased summary of comment on conclusions] Conclusion - The consultation released in 2001 makes different conclusions than the current consultation released in 2002.
  28. Response: The initial health consultation released in 2001 was based on the data available at that time. Upon reviewing and answering public comments, it was determined that more information might be needed in order to answer the concerns of the residents. The current and second consultation used the sampling data obtained during ATSDR's May 2002 exposure investigation to draw conclusions.

Ohio Department of Health

  1. Comment: Page 1, Paragraph 2: "groundwater due the unique geography of the area". I would change "geography" to geology. As indicated in the next sentence, it is the presence of a significant N-S trending fault line in the immediate vicinity of Cady Road area that is the likely source of the natural gases that pose the problem to area residents.
  2. Response: ATSDR changed the word "geography" to "geology".

  3. Comment: Page 1, Paragraph 2: "No studies are available to determine if the local aquifer has been impacted by oil and gas extraction activities." It is my understanding that the ODNR Division of Oil and Gas did an extensive investigation at the time of the state involvement at this site in 1995 that concluded that the gas problem in the area was the result of the unique geological conditions referenced above. These investigations indicated that there was no evidence that local Oil and Gas exploration and production activities were a source of the gas problem impacting residents along Cady Road. There seems to be a persistent tendency throughout the health consultation document to suggest some sort of linkage between the methane problem and these oil and gas-related activities without providing any clear evidence of a connection outside of the elevated sodium levels in some residential wells tested by ATSDR.
  4. Response: ATSDR did not draw any conclusions about the source of the gas problem impacting residents. ATSDR did reference ODNR's investigation and conclusion that gases in water are a natural phenomenon. The fault line as a possible source of the gas problem was acknowledged in the document. ATSDR has reworded its statement "No studies are available to determine if the local aquifer has been impacted by oil and gas extraction activities" to more clearly define its intent. The statement was replaced with "Except for the investigation done by ODNR (referenced above), no other studies or sampling data are available to determine if the local aquifer has been impacted by oil and gas extraction activities".

  5. Comment: Page 2, Last Paragraph: "Other than one private well being analyzed for chemical contamination by the CCBH and the ODNR…" The sample in questions was actually taken by the Ohio Department of Health's Private Water Group on Feb. 2, 1995. The sample was analyzed for the full scan of VOCs and pesticides, plus inorganics. The analytical work was done by the ODH lab. No VOCs or pesticides were detected and the inorganics were within drinking water parameters.
  6. Response: The reference to CCBH was corrected to indicate that ODH took the sample.

  7. Comment: Page 6 and 7: Gas results are alternatively referred to in the text either as % of the LEL, straight % methane, and/or parts per million (ppm) and then are presented in Table 1 in Appendix D in parts per billion (ppb). This gets kind of confusing when the reader is attempting to determine what levels of methane were detected at what sampling locality at what time using which sampling technique. You might want to stick with either ppm or ppb and then put in parenthesis next to it the corresponding level in % of the LEL. I presume the use of ppb in Table 1 for the grab sample results is erroneous you meant to use ppm as suggested in the text. I think this needs to be corrected or clarified.
  8. Response: Corresponding levels of methane in different units were added to the document for clarity.

  9. Comment: [Paraphrased and summarized] Page 12, Regarding the conclusion statements for combustible gases and hydrogen sulfide: The hazard ranking statement decided upon for this site goes back to my continuing problem with the way ATSDR expresses these conclusions in PHC and PHA documents. As this methane problem has existed in this are for the past 50 years, it is hard for me to refer to this issue as "urgent" public health hazard. Explosive levels of methane were detected in two wells at two residences in the immediate vicinity of the wellhead. It is unlikely that methane concentrations would remain at these levels in the ambient air any distance from these wellheads. Short-term sampling of indoor air in impacted homes registered methane levels as high as 9% of the LEL (<0.5% methane) and 19% of the LEL (roughly 1% methane) in the basements of two of the nine homes sampled during the 20-minute interval in which the water was being flushed through the distribution system. These levels are below the 25% of the LEL used as a criteria by hazmat teams for the evacuation of a building. Eight-hour SUMMA canister samples did not demonstrate the same elevations of combustible gases. Methane concentrations from these canister sampling are described as being "at low levels in all indoor samples" but these levels are not documented in the tables presented in Appendix D. The maximum level of methane detected at the source (well water after the well but before any treatment or filtration systems) was 11,000 ppm (1.1%) compared to a LEL of 5%. Hydrogen sulfide gas was detected as high as 28 ppm in one home in the basement near a sink where water was being run and at 5 ppm in the same basement away from the sink. Data were not provided with regard to H2S levels detected in indoor air in the other 8 homes sampled so I assume these levels were low. While these results warrant public health concern, I do not believe this situation poses an urgent public health hazard. People currently are not being exposed to methane at levels that pose an immediate hazard. No methane or associated gases were detected in any of the three ambient air 8-hour samples collected in residential yards. Hydrogen sulfide levels, while detected at health concern levels in one sampling event in one household, do not appear to pose a significant health hazard in any of the other homes sampled. Under the right set of circumstances, methane levels could pose an explosion or fire hazard to a residence. Under the right set of circumstances, elevated hydrogen sulfide levels could result in adverse (but not lethal) health effects to some residents. To my knowledge, to date, in the past 50 years, these conditions have not led to any explosions or fires within any residence. I would term this site a potential public health hazard based on potential for conditions to develop that might be hazardous to these residents.
  10. Response: Although methane has been reported to be a problem in the area for almost 50 years, and methane in groundwater is reportedly a common occurrence in Ohio, ATSDR based its conclusions on the sampling that was performed in May and September of 2002. It is possible that conditions have changed over the years, and that the current sampling represents a different set of conditions than over the past 50 years. It is unknown whether residents have lived with these particular levels or whether it's a more recent condition. ATSDR classified the occurrence of methane in the levels that we found to be an urgent public health hazard based upon ATSDR' health hazard categories. An "urgent public health hazard" category is used when there is the presence of a serious physical hazard, or a hazard that could cause adverse health effects in less than one year. In comparison, the "public health hazard" category, one step below the urgent category, is used for a hazard that could cause adverse health effects after exposure longer than 1 year. As the commenter noted above, "Under the right set of circumstances, methane levels could pose an explosion or fire hazard to a residence. Under the right set of circumstances, elevated hydrogen sulfide levels could result in adverse (but not lethal) health effects to some residents." According to the local fire chief a pump house did burn in the area and a flash fire attributed to stripped wires on the pump. Area residents have consistently reported the ability to light fumes off of running water in the sink and bathroom (which has been filmed by local newscasters). Two wells are not able to keep a cap on the wellhead, because of the pressure from gases. Explosive levels of methane and other combustible gases were detected in the air near these uncapped wellheads. Since there is a potential for methane to buildup inside the home at any time, and the residential homes are not currently monitored, ATSDR classified the site as an urgent public health hazard due to the explosion and fire risk. ATSDR's health hazard categories have been added to the document as Appendix G.

  11. Comment: [Paraphrased and summarized comment] Regarding the recommendation: My assumption is that this recommendation is to hook the remaining homes on Cady Road currently using private wells to the municipal water system. One of the things always stressed to our program by ATSDR when making any recommendations in a PHC or PHA is to make sure that there is somebody out there to carry your recommendation out. Who's responsibility is it to provide a safe drinking water supply?
  12.  

    Response: ATSDR, whenever possible, identifies an entity responsible for carrying out our recommendations before the actual recommendation is made. In this case, ATSDR was aware of the history of attempts to obtain an alternate water supply and the problem with responsibility. ATSDR feels that the residents of Cady Road should understand that the best possible remedy to the situation would be to obtain a different water supply. It is not always possible to have agencies agree to follow our recommendations as ATSDR is not a regulatory agency. And in some cases, it is not immediately feasible to complete the recommendation. Based on information gathered during our investigation, it appears the most appropriate parties to take action in obtaining an alternate water supply are the City of North Royalton and the residents on Cady Road.

  13. Comment: [Summarized and paraphrased comment] Currently, people using private wells in Ohio are held to be personally responsible for insuring the safety of their own drinking water supply. The situation is similar to the case of radon gas, a naturally-occurring contaminant that may pose an indoor air risk to homeowners living in areas prone to radon gas production. In the case of radon, it is the homeowner's prerogative to test his home and if radon is present, to pay for an abatement device to limit his or her's radon risk.
  14. Response: ATSDR agrees that ultimately residents are responsible for his or her own health and safety, especially for private well water which is not subject to the Safe Drinking Water Act. Therefore, ATSDR has provided the residents of Cady Road the best possible information for them to make an educated and informed decision regarding the safety of their water supply and ways to mitigate exposure, including seeking an alternate water supply.

  15. Comment: [Summarized and paraphrased comment] Residents have had the opportunity in the past to hook up to city water or install engineering controls, but many did nothing. Currently, residents still do not think that the methane problem is significant enough to warrant the cost of hooking up to city water. What the solution is to this dilemma currently escapes me. Community health education with regard to the risks from elevated levels methane, hydrogen sulfide, and sodium in well water? Additional emphasis on installation of individual water treatment systems? Maybe these should be added to the list of additional recommendations made by ATSDR in the document. [Note: Information on treating methane and hydrogen sulfide in water was provided.]
  16. Response: ATSDR is unaware of any sampling in the past that resulted in methane levels as high as the sampling that was performed in May 2002. Therefore, in the past, residents may not have known about the potential safety hazards of methane in their water. Currently, there are concerned residents who want to hook up to city water, however, 60% of the residents (60% by frontage) have to agree to get city water in order for the city to install water lines on the road. The amount of property owned on the road varies significantly among residents. This policy may not allow some residents who would like the water to obtain it. ATSDR has also recommended interim measures, such as water treatment systems. In this final version of the consultation, ATSDR has included discussion on water treatment systems.

  17. Comment: [Summarized and paraphrased] Conclusions: While methane levels certainly represent an explosion hazard, methane occurs naturally in geologic formations in many areas in Ohio. Elevated methane levels do not pose a public health hazard, rather they are a safety issue that each well owner needs to address.
  18. Response: ATSDR acknowledges that other agencies may not term elevated methane levels a public health hazard, but rather refers to explosive gas levels as a safety hazard. ATSDR's policy is to include safety hazards in evaluating public health and includes naturally occurring materials such as asbestos and radon.

  19. Comment: [Summarized and paraphrased] Individual water treatment systems can be installed for a fraction of the cost of water lines. Groundwater is still a good reliable source of drinking water and I hope that our agency would not be in a position to discourage its use. The methane is a safety hazard, and hydrogen sulfide is ubiquitous across the state. State and federal agencies should respond by providing relevant information on effective methods of treatment and removal of the constituents of concern. I am concerned by the precedent such a report could establish and the implication for water quality in private water systems statewide.
  20. Response: ATSDR is not suggesting that groundwater is not a good source of drinking water. ATSDR is aware that many private well owners across the state and even country deal with contaminants in their wells, such as methane, hydrogen sulfide, bacteria, etc. Most contaminants can be treated or removed from water with the right engineering solutions. ATSDR agrees that there are some situations where treating the water is the best solution to a problem, especially where the treatment is simple and inexpensive. However, the levels of explosive gas and hydrogen sulfide in some homes on Cady Road would require significant treatment, more than provided in an average home system. Additionally for any treatment system to be reliably protective of public health, it must be properly designed, tested and maintained. It is best public health practice to recommend a solution which is a reliable solution. This is even more critical with an acute hazard. ATSDR acknowledges that there are water treatments that could help reduce the levels of gases in the water and even recommends them as interim measures. However, ultimately ATSDR believes that the most simple and most protective solution is to obtain an alternate water source.

Ohio Department of Natural Resources

  1. Comment: [Summarized comment] Page 1, Paragraph 2. The report goes beyond its stated purpose which is to "identify potential human exposures and possible health effects related to chemicals detected in private well water and indoor and outdoor air data…" The report makes ambiguous statements regarding possible sources. Statements regarding the source of chemicals should be removed from the report, or the report should reference the findings and conclusions of the Divisions's summary report, dated May 15, 1995, which stated that natural gas in water wells was a natural phenomena, not related to commercial oil and gas exploration or production operations.
  2. Response: Please see the response to comment number 16.

  3. Comment: [Paraphrased and summarized comment] The statement that "many of these (oil and gas) wells have a history of violations related to maintenance and accidents" is a broad and inaccurate generalization, and could mislead local citizens to conclude that oil and gas wells are not being adequately regulated, and have not been adequately regulated as a possible source of natural gas in their water wells. As part of its 1995 investigation, the Division reviewed oil and gas well construction records, reviewed compliance histories and conducted numerous inspections of oil and gas wells and a Class II brine injection well located in Section 15 of Royalton Township. The Division found no well construction problems, accidents or violation that had any relevance to the presence of natural gas in the local aquifer. Since 1985, problems identified included a 1986 oil storage tank fire that was confined to the spill control dike, minor paraffin accumulations around wellheads, soil erosion on a lease road, and a shallow gas link leak. Again, these are not problems that can cause natural gas in water wells developed at depths generally exceeding 100 feet below surface.
  4. Response: Comment noted. ATSDR did not draw any conclusions from the statement - its purpose is to summarize and highlight the history of oil and gas wells.

  5. Comment: The statement that "no studies are available to determine if the local aquifer has been impacted by oil and gas extraction activities" is not true, unacceptable, and should be deleted from the report. This statement ignores the diligent efforts of the Division inspectors and geologists who conducted extensive evaluation of oil and gas activities near Cady Road as part of our investigation. The Division concluded that natural gas present in well water was a natural phenomena resulting from local geological conditions, and was not caused by violations or operational problems at oilfield operations in the area. (Supporting references for the investigation were provided).
  6. Response: Comment noted. Please see the response to comment 16. When ATSDR referred to "No studies", it was referring mainly to sampling data. In addition, ATSDR did reference the ODNR investigation and its conclusions. ATSDR has reworded the statement for clarification.

  7. Comment: Page 1, Paragraph 3: Based upon our own interviews with local residents, and observations at ATSDR public meeting in May 2001, the Division would be interested in knowing how many local residents reported the various "health concerns including dizziness, lightheadedness, passing out, shortness or breath, fatigue, headaches, etc." Would it be possible to include a table summarizing the number of local residents who reported experiencing these health concerns?
  8. Response: ATSDR did not conduct a health survey and therefore can not tally the numbers of individuals that reported each symptom. Health concerns were summarized based on public meetings, a public availability session, written affidavits, and personal communication. About 20 individuals expressed concerns about water quality and odors, about 15 individuals expressed concerns about water quality and not specifically odors, and about 7 individuals specifically expressed concerns about health, including those listed above.

  9. Comment: Page 2, Paragraph 1: As an update, there are now eight producing oil and gas wells in Section 15 of Royalton Township.
  10. Response: The number of producing wells was updated.

  11. Comment: Page 2, Paragraph 4: Methane and hydrogen sulfide are dissolved gases, not volatile organic compounds. The report is inconsistent in its classification of these gases.
  12. Response: Please see the response to comment 1.

  13. Comment: Page 2, Paragraph 4: The report is inconsistent in reporting units of measurement for gas. Since the potential for accumulation of natural gas at explosive concentrations is the primary health concern identified by this consultation, the Division recommends that all measurements include reporting as a percentage of the LEL.
  14. Response: Please see the response to comment 18.

  15. Comment: Page 2, Paragraph 5: The statement that only one private water supply was sampled and analyzed for chemical contamination is not accurate. In 1982, 1984, and 1987, the Ohio EPA or Division collected water samples from two private water supplies at the Byzantine Monastery at 6688 Cady Road. Chloride concentrations ranged from 48 to 131 mg/l. The Division does not challenge ATSDR's position that additional data was useful to determine whether a health threat exists.
  16. Response: Comment noted.

  17. Comment: Page 4, Paragraph 1: Again, the speculative source of chloride is outside the scope of the ATSDR's consultation and expertise and should be deleted. As an alternative, the ATSDR could reference the Division's determination as presented in our 1995 report that there is no evidence that indicates that the aquifer is impacted by oilfield brine.
  18. Response: The sentence in question has been deleted.

  19. Comment: Page 5, Paragraph 2: Again, ATSDR makes speculative statements regarding the source of natural gas in the aquifer.
  20. Response: The sentence in question has been deleted.

  21. Comment: Page 6, Paragraph 2: Sentence 1 is incomplete.
  22. Response: The sentence in question has been corrected.

  23. Comment: Page 6: Again, gas concentration data should be consistently reported as a percent of the LEL. In addition, ATSDR should describe sample locations in more detail. It is not clear where in the basement the highest measurements were recorded. Location and persistence would seem to be critical factors to any meaningful assessment of gas concentrations.
  24. Response: Gas concentration data have been corrected to be more consistent - see response to comment 18. Real-time air screening performed was intended to screen the water for gases. Therefore, the readings obtained were generally within a few feet of the source of water. The 8-hour SUMMA canister samples were intended to measure general ambient air quality, and to determine the persistence of the gases. An ignition source near running water, or an ignition source in an unventilated or poorly ventilated room where water is used, would pose a risk of fire and explosion.

  25. Comment: Page 6, Paragraph 3: Again, methane is not a VOC.
  26. Response: This has been corrected to reflect methane as a gas.

  27. Comment: Page 7, Paragraph 1: ATSDR notes that short term peak concentrations of methane were detected at "low levels in all indoor samples, except one". How low were these concentrations in relation the LEL? Did ATSDR look for any statistical relationship between gas concentrations and distance from source in inches or feet that would be useful in assessing risk?
  28. Response: The results of the 8 hour indoor air samples were included in the table in Appendix D. Methane was detected from 13 to 60 ppm in 8 out of 9 samples, over an 8 hour time period. This is < 1% of the LEL. The purpose of the 8 hour average samples was to 1) determine the persistence of gases in indoor air, and 2) determine if there were any VOCs in indoor air that would pose a health threat from chronic exposure. To assess a statistical relationship between source and gas concentrations, real time monitoring would need to be completed, instead of 8 hour averages. Obviously, the risk of fire and explosion is greater if there is a source of ignition near the source of gases - the running water. ATSDR did not measure a statistical relationship of gases and risk with distance from the source.

  29. Comment: Page 8, Paragraph 4: With regards to the two highest gas concentrations (9% and 19% LEL), the report is not clear where measurements were recorded. The report simply states that these concentrations were detected "in the basement". Again, the report would be clearer if ATSDR provided information regarding the distance between the gas source (tap) and the instrument, and the persistence of the readings after the water is turned off. EPA recommends evacuation when gas concentrations reach 25% of the LEL. Does EPA suggest this level of precaution if these concentrations are only measured directly at the source?
  30. Response: Please see the response to comments 36 and 38. EPA recommends immediate evacuation when gas concentrations reach 25% of the LEL for workers in an occupational setting that have continuous monitors. At 10 - 25% of the LEL, EPA recommends that workers monitor the area with extreme caution. However, residential homes are not continuously monitored so that residents can evacuate if the levels become a fire or explosion hazard. For this reason, ATSDR concludes the current and potential levels of methane in the water poses an urgent public health hazard, and action should be taken to mitigate exposure.

  31. Comment: Page 10, Paragraph 1: Same comment (as previous).
  32. Response: Please see the response to comment 38.

  33. Comment: Page 13, Recommendations: In addition to these recommendations, there are a variety of commercially available aeration systems that would remove dissolved gases from well water prior to entering the house. The Division recommends that ATSDR include a reference to these systems in the recommendations.
  34. Response: ATSDR did recommend aeration systems as an interim measure. ATSDR still believes that overall, the best way to mitigate exposure is to use a different water source. Please see the discussion on page 13, added to this final version.

City of North Royalton

  1. Comment: [Summarized and paraphrased] More information is necessary to enable the residents to choose their best course of action.
  2. Response: ATSDR performed sampling in order to determine if residents were being exposed to any chemicals that warrant public health concern. ATSDR found that the sampling results were sufficient to draw conclusions regarding the water supply for most residents on Cady Road. ATSDR agrees that more information regarding the extent of contamination, or determining the number and severity of other houses that could possibly be involved is important and necessary. ATSDR has added this statement to the "Recommendations" section.

  3. Comment: [Summarized and paraphrased] ATSDR's involvement at the site should include throughout the process the local agencies and City who have been involved for years and ATSDR should work cooperatively with them to provide complete and accurate information to those affected.
  4. Response: Comment noted. ATSDR agrees that it is important to work with any local agencies or entities that are involved with the site for a more effective public health message.

  5. Comment: [Summarized and paraphrased] The recommendation regarding "provide an alternate whole-house water supply", is overly broad in that it does not consider practices commonly employed to mitigate, if not eliminate, the presence of dissolved combustible gases within well water prior to the point of use within a residence. [Technical information on aeration treatment systems was supplied, authored by a private contractor].
  6. Response: Please see the response to comment 41.

  7. Comment: [Summarized and paraphrased] The Cady Road health consultation sensationalized the data and observations, and cannot support a quantitative conclusion that a legitimate public health hazard or risk exists, causing alarm, and also disturbing and damaging property owners.
  8. Response: Comment noted. Physical hazards differ from chemical hazards in that physical hazards are a public health hazard due to their risk of adverse safety or health outcomes. In order to have a quantitative conclusion that a fire or explosion will occur, an explosion or fire would actually need to occur, or have gases in their home within the explosive range. ATSDR's mission is to protect public health, and prevent harmful exposures. ATSDR does not believe it sensationalized any data to cause alarm. Rather, information regarding the sampling data and possible outcomes was provided to all stakeholders involved, including: local, state, federal agencies, community members, and individual residents. It is normal and understandable that residents were alarmed and surprised by the sampling results. ATSDR understands that the results may be damaging to property values; however, health and safety are normally a priority over property values. Once the problem is addressed and solved, property values will return to normal or increase.

  9. Comment: [Summarized and paraphrased] The credibility of the report is further damaged and suspect by examining the obvious intent of the agency to sensationalize the initial release of their report. The agency's press release uses bold type to announce an urgent public health hazard. Why wait three months to announce via a press release, that an "urgent" public health hazard exists? It is standard practice for an investigator to take or demand immediate evacuation and/or remedial action when explosive conditions are found within a confined space area.
  10. Response: ATSDR always issues a press release, in identical format, for all health consultations and public health assessments being released for public comment. The press release was not the first time ATSDR announced its sampling results. Once ATSDR received the laboratory results, a fact sheet was sent (prior to the press release) to all stakeholders - local, state, federal agencies, and community members, providing our preliminary results and interim measures to mitigate exposure. We explained to individual residents what we had found and what it meant while on-site and after sampling. ATSDR spoke personally to many of the stakeholders to inform them of the sampling results. The press release was designed to announce the availability of the document and the public meeting. ATSDR designated the potential for fire and explosion as "urgent" because any physical hazard possible from a short-term (less than 1 yr) exposure is to be classified as "urgent". Please see ATSDR's public health hazard categories that were added to this document in Appendix G. If ATSDR had found explosive conditions inside the home, ATSDR would have advised the residents to evacuate.

  11. Comment: [Summarized and paraphrased] ATSDR staff obviously felt comfortable with the "near explosive levels of methane" in the homes for at least 3 months, when they finally issued their health warning. I'm going to conclude that the investigators were comfortable with these levels because they understood that the dangerous methane levels and conditions within the homes they encountered and documented, were created and induced by their own exaggerated testing activity. Therefore, it would be unlikely for these near explosive levels to reoccur through normal household activity by the residents of these homes.
  12. Response: See the response to the previous comment. ATSDR provided warnings to the residents at homes where we found high levels, and provided fact sheets to all stakeholders involved, long before the health consultation was issued. ATSDR did not exaggerate testing activity. ATSDR flushed the water for about 20 minutes to sample water from the source - the aquifer. This is a standard method of drinking water sampling. Levels of gases increased greatly in a few homes within 30 seconds of turning the water on. In other homes, it took a few minutes to reach the same high level. ATSDR does not believe that these methods of water sampling exaggerate normal household activity.

  13. Comment: [Summarized] City officials are confounded by the report's insistence that municipal water service is the only solution. The most commonly recognized cost effective solution of venting of the actual well casing is labeled as a lower priority remedy. The cautionary note of "to be effective, this mechanism would require advanced, and perhaps costly engineering designs" is a gross contradiction. Proper venting of the well casing is easily accomplished and is an extremely cost effective solution to managing gas in water wells.
  14. Response: Please the response to comment 41. ATSDR did not observe venting of the wellhead to be an effective solution to methane gas in water. Venting of the wellhead would reduce methane levels only in the top portion of the well. The lower portion of the well where the water is drawn will still contain dissolved gases such as methane. One water well did not have a cap, thereby freely venting the methane into the atmosphere, but high levels of methane were still coming through the tap into the home. Only a more advanced aeration treatment system would help to reduce the levels, which as stated in the document, are systems that would require professional engineering or installation.

  15. Comment: Page 1, Paragraph 1: Municipal water has been provided to the corner of State and Cady road since the 1950s when the whole city was served. In 1987 the waterline extended 1082 feet west at the request of the benefited property owners. These benefited properties were assessed for the cost of installation. The rest of the road was not served because of a petition against the project signed by 15 of the 23 property owners. Many of those against the project still live in the affected area.
  16. Response: Comment noted.

  17. Comment: Page 1, Paragraph 2: Only one person complained initially to ATSDR.
  18. Response: This was stated in paragraph 1: "A resident of Cady Road petitioned the Agency…". Paragraph two compiles concerns from several residents on Cady Road, collected through public meetings, affidavits, and verbal communication.

  19. Comment: Community: The report needs to clarify ATSDR's definition of "Community". As I understand it, this is not the layman's definition, but in their report it refers only to the study area.
  20. Response: Yes, the word "community" in the report refers to residents on Cady Road.

  21. Comment: Page 2, Paragraph 2: Water extended by petition and at expense of property owners.
  22. Response: Comment noted.

  23. Comment: [Summarized and paraphrased] Page 2, Paragraph 4: In 1995, the city held public meetings for the study area. The residents had a chance to express their concerns at that time. Concerns were addressed by various City Council Committees both in 1995 and again in 1997. The matter was fully discussed, all the various reports reviewed, but the property owners never specifically requested city action. As allowed by state law, the city assisted the concerned owners in circulating a petition requesting a waterline, but only received 29% of the front footage, instead of 60% required by State law. The concerns disappeared until the 2001 ATSDR public meeting.
  24. Response: According to conversations with several current Cady Road residents, their concerns over water quality never disappeared. It is our understanding that a reliable understanding of the water conditions in the Cady Road area was not available during the earlier discussions of providing public water to the residents of Cady Road. We hope now that these conditions are better understood, the residents can make a more informed decision in the future.

  25. Comment: Page 8, Paragraph 4: Methane is the principal component of natural gas piped directly into millions of homes and used without incident. Properly handled methane is a safe and useful product.
  26. Response: Natural gas piped into homes is regulated and the amount is controlled. Natural gas is safe when it is used for combustion to provide heat. Natural gas is not safe if the gas is not fully combusted or the gas itself escapes into indoor air, such as during a gas leak. For these reasons, methyl mercaptan (an odorant) is added to natural gas so it may be detected by smell, and alert home occupants of its presence. However, methane from the groundwater is not controlled or measured, nor is methyl mercaptan added to ensure its detection by home owners.

  27. Comment: Page 9, Paragraph 2: The professional to vent the wells is a certified well driller licensed by the state of Ohio.
  28. Response: Comment noted. In some cases, the professional may need to be a professional engineer.

  29. Comment: Page 10, Paragraph 5: The 15 to 20 minute flushing used in the test I believe to be excessive. As a well owner I and my family do not run the water for extended periods like this due to the possibility of running the well dry. For a normal faucet 20 minutes running would amount to 60+ gallons. This is equivalent to several loads of laundry all being done concurrently.
  30. Response: Flushing the water for 15 - 20 minutes or until the water reaches standard temperature and conductivity is a standard EPA practice for sampling drinking water.

  31. Comment: Page 11, Paragraph 2: Hydrogen sulfide can be treated at the wellhead by the same venting process that will release methane.
  32. Response: Agreed, venting can reduce both hydrogen sulfide and methane and other gases. However, well head venting is not sufficient for higher levels of these gases. One of the two homes with the highest measured gases had a vented well head (see the discussion on treatment systems).

  33. Comment: Page 12, Paragraph 1: I don't know anyone who keeps their paint and solvents in a detached structure. Most keep in their basement where they won't freeze. I do so myself without incident for 35 years as a private homeowner.
  34. Response: Best public health practice dictates storing all chemicals away from living spaces. A detached structure would be ideal. A basement may be away from living space in some cases.

  35. Comment: Page 12, Conclusions: Define "urgent". ATSDR has been involved in this for almost 2 years. The sampling used in this report was done in May 2002, and we obtained a copy of the report in September. In my world, 4 months is not "urgent".
  36. Response: Please see the response to comment 46 and 47.

  37. Comment: Page 12, Conclusions: Don't agree that chemicals in a private well are a "public" health hazard. The residents could remove the hydrogen sulfide from their wells if they choose to do so.
  38. Response: Comment noted. ATSDR assesses current conditions as the primary pathway in evaluating public health hazards. The term "public health" is used to describe residential exposures, no matter how many people it refers to, and is used as opposed to "occupational health". ATSDR evaluates private well water for public health hazards.

  39. Comment: Page 12, Conclusions: The houses exist now and have for 50 years. The houses are not airtight. This is obvious since there is sufficient air for combustion of the furnaces and water heaters. From our lack of explosions, it would appear that the gases are dissipating through these "natural" leaks.
  40. Response: Comment noted. It is possible and likely that the houses are not airtight. However, the potential is there for gases to build up - two wellheads have reportedly exploded in the past on Cady Road. In addition, much of the concern is for sources of ignition near the water and certain rooms and areas of the house, not necessarily a concern for the entire house.

  41. Comment: Page 12, Conclusions: In my home the gas dryer burns air from inside the house and exhausts the products of combustion and the moist air to the exterior. I believe this more or less constant air change during the washday may be sufficient to prevent the accumulation of the gases of concern.
  42. Response: This form of ventilation is not recommended (ATSDR recommends the area is vented with air from the outside). The two ways to do this are to dilute the methane indoors with outside air or actively exhaust the methane to the outside.

  43. Comment: Page 12, Conclusions: Macomb County Michigan health department recommends calling a registered well water contractor to deal with methane in water wells. I called mine, Depew well drilling and they said they were aware of the gas problems on Cady, Ridge and Boston roads. They believe they have talked to most of the well owners in the area. They recommend a vented system consisting of a holding tank open to the atmosphere to receive water from the well and allow the gas to bubble off, and a second pump to provide pressure from the house system. They could recall of no one who took their advice.
  44. Response: Agreed, venting can reduce hydrogen sulfide, methane and other gases. However, passive aeration may not be sufficient for higher levels of these gases (see the discussion on treatment systems).

  45. Comment: Page 12, Conclusions: I agree I keep my well cap on at all times unless actively working on the well. I actually checked it to be sure it was tight. Actually its not tight, there is space between the cap and the well casing that allows for air to enter the well. This same space would allow for any pressure in the well to equalize with the atmosphere and hence prevent a major build up of gases.
  46. Response: Please see the response to comment 48. Although this may help reduce the level of gases, ATSDR observed that "venting", or even removing the cap, did not prevent gases from building up, and entering the home through the water. In some cases, audible sounds of bubbling gases could be heard, and high levels of methane were observed in water coming into the home, even with the well cap removed.

  47. Comment: Page 15 and 16, References: Of the 41 cited references, only one is a standard and not even a public health standard. Shouldn't an urgent public health issue cite public health standards, for example the EPA drinking water standards, the health department standards for private well water, etc? It appears that many of the references cited are research papers from various technical publications.
  48. Response: ATSDR used public health standards such as EPA's drinking water standards when they were available. There are no "public health standards" for methane in drinking water or air for a residential scenario. Therefore, ATSDR used information from EPA's standard operating procedures on hazardous atmospheres. The only other policies for methane come from landfill migration of methane. This exposure pathway has a different major concern, which is methane migrating into the home through the foundation, not through the water.

US EPA

  1. Comment: It is our understanding that this health consultation is not intended to serve as a document to support a Superfund remediation, or a study to determine the source of natural gas present. An introductory statement should make it clear that the scope of the health consultation is to protect the health of the residents of Cady Road at their homes, and is not intended to be a complete or full risk assessment of all environmental risks in the entire area. To determine any other less immediate exposure pathways that could pose some potential level of risk to persons outside of the impacted residences would require additional study.
  2. Response: ATSDR agrees and has added an additional "purpose" statement at the beginning of the document.

  3. Comment: Page 1, Statement of Issues: The second sentence appears to understate somewhat the ODNR investigation, Reference 2 in the consultation. The first paragraph of the ODNR May 15, 1995 letter contains the statement "The division has concluded that the natural gas which is present in your water is the result of natural phenomena, and is not related to any oilfield operations in the area".
  4. Response: Please see the response to comment 7 and 16.

  5. Comment: Statement of Issues: The last three sentences lead the reader to imply that the oil and gas extraction activities are the cause of the shallow groundwater contamination in the Cady Road area. The "…violations relating to maintenance and accidents…" that are referred to were actually relatively minor surface brine spills and similar actions which would make them an extremely unlikely source for the natural gas in the drinking water aquifer. Again, the ODNR has studied the potential for oil and gas extraction activities to impact the aquifer in the immediate area and have also reviewed available studies of the area geology to reach the conclusion in the previous comment. Since the purpose of this health consultation is to identify contaminants in the Cady Road resident's well water and air, and to determine the possible health effects, we suggest that all references to oil and gas extraction wells and activities in the area, or at least references that could imply that these activities are the source of the natural gas in the aquifer be removed.
  6. Response: Comment noted. However, concerns about oil and gas extraction activities have been expressed by the community. Therefore, ATSDR discusses what we do know about oil and gas extraction activities to provide a perspective for residents. ATSDR did not draw conclusions about the source of gas in the aquifer, and made that point clear in the document and in addressing these public comments.

  7. Comment: [Paraphrased] Background: The document does not acknowledge all the work done by the ODNR and others to attempt to address the complaints from a resident starting in 1995.
  8. Response: ATSDR acknowledges the work done by ODNR and other agencies in the section in the background section of the document.

  9. Comment: A statement is made that there are "concerns about the quality control and assurance issues for this sampling event…" This statement should be removed since it is unqualified and therefore could potentially affect our office's credibility. The US EPA's Cleveland office personnel that conducted the sampling event used appropriate equipment for collecting grab samples, followed established quality assurance and quality control methodology, and properly documented the results.
  10. Response: ATSDR's main concern about the grab samples is the evacuation of the canisters. The pressure should be recorded before and after obtaining the sample to ensure that the canister is fully evacuated. This procedure was not apparent in the 1998 grab air samples. In addition, grab samples, which take a sample of air over about 10-20 seconds, are not representative of residential exposure. ATSDR removed the generic sentence referring to quality control and assurance and specifically stated the reason we did not use the data.

  11. Comment: Page 5, Volatile Organic Compounds and Dissolved Gases -Again, speculation as to the cause of the natural gas present in the aquifer does not need to be addressed in the document, and should be left to the experts at the ODNR.
  12. Response: The statement in question has been deleted.

  13. Comment: Page 6, Air screening results - The gas that was used to calibrate the LEL meter is not identified. Because the measured results for a gas like methane can vary greatly depending on the calibration gas used for the equipment, the calibration gas should be included in the document.
  14. Response: The FID meter was calibrated with methane.

  15. Comment: Page 8, Public Health Implications - The statement that "none of the gases or organic compounds measured in the drinking water pose an ingestion hazard…" should be included in the "Conclusions" section of the document.
  16. Response: A statement regarding the absence of an ingestion hazard was added to the Conclusions section.

  17. Comment: Page 8, Methane - The use of a Superfund "action level" of 25% of LEL does not seem appropriate for this situation. That level includes a safety factor that is intended for use when the gas being detected is unknown and the accuracy of the meter reading may be in question. When the gas present is known (methane) and the readings are reliable, then it should be the fire and explosion experts, such as the Fire Department or State Fire Marshall, who should determine the hazard present.
  18. Response: There are no "action levels" for a residential scenario. The best guideline for this situation was found to be EPA's Standard Operating Safety Guide. The gas being detected in the homes is an unknown combination of gases, not just pure methane. In addition, the homes are not being monitored continuously. For these reasons, and ATSDR's professional judgement which tends to err on the side of being protective of public health, ATSDR used the Superfund guidelines as one of the bases for our discussion and conclusions.

  19. Comment: It should be noted that the North Royalton Fire Department on numerous occasions called on a resident at their request to collect gas measurements and did not find explosive levels of gas. Some of the residents of that neighborhood have lived there for up to 40 years or more with no reports of explosion in their homes.
  20. Response: One of ATSDR's missions is to prevent public health hazards when possible, and mitigate exposure to any current public health hazard. If an explosion had already occurred in a home, the situation of gases in the water would most likely have already been resolved. However, there have reportedly been explosions at two wellheads on Cady Road, and our sampling from May 2002 resulted in levels of gases high enough to warrant serious health and safety concern. In addition, it is possible that changes have occurred over time and worsened the conditions, or that conditions are variable over time. In addition, two pump fires have reportedly occurred on Cady Road and area residents have consistently reported the ability to light fumes off of running water in the sink and bathroom (which has been filmed by local newscasters).

  21. Comment: The US EPA has no regulatory authority over private drinking water wells and can not require the owners to have their water meet MCLs or to be closed. The US EPA regulations promulgated under the Safe Drinking Water Act apply to public water systems. Public water systems are defined as those systems providing drinking water to at least 25 people or 15 service connections for at least 60 days per year. The MCLs and SMCLs can still be used to determine the relative risk that the water produced by private drinking water wells may pose.
  22. Response: Comment noted.

  23. Comment: Appendix B, page B-2: The second footnote should be proceeded by double asterisks. Also, in the same footnote, a "petroleum product" is a known substance. It should be replaced with "oily sheen" which is what was observed on the pond.
  24. Response: These changes were made to the document.

Resident Comments

  1. Comment: [Summarized and paraphrased] Why did the on-site representatives concern themselves fully with defining the parameters of the study, but blatantly ignore any possible health impact by refusing to address any mitigation measures?
  2. Response: The most protective solution to the problem of gases in well water is to obtain a different source of water. However, ATSDR did address mitigation measures such as ways to prevent the buildup of gases, and interim recommendations such as treating the water to release gases. ATSDR addressed these recommendations in the document, in person at the public meeting, and through verbal communication to the residents whose water ATSDR sampled. ATSDR did not go into detail about the specific treatment systems at the public meeting because ATSDR had not evaluated different treatment systems and their efficiencies. ATSDR has added discussion of water treatment systems to the final version of this document.

  3. Comment: [Summarized and paraphrased] Why were the water treatment systems bypassed for sampling, even though it was stated in the report that real-time monitoring indicated that water treatment systems in the homes sampled did not eliminate the release of gases into ambient air?
  4. Response: Bypassing the water treatment systems was not done solely for detecting methane. Several homes have treatment systems that treat the water for other contaminants such as metals. ATSDR wanted to sample the source of water, and to have results that could be consistently compared to one another, independent of the treatment system. ATSDR thought it was important to determine if there were any contaminants present at levels of concern in untreated water, in case the treatment system malfunctioned or was not maintained. In addition, several residents had no treatment system in place.

  5. Comment: [Summarized and paraphrased] For the recommendation of "provide an alternate whole-house water supply to the remaining homes on Cady road that do not currently have access to municipal water", why did ATSDR not explain any other alternatives if they were not solely recommending municipal water?
  6. Response: Alternatives besides municipal water include cisterns, digging the well further down or in a different location to access a different aquifer, or installing an effective whole-house treatment system, which effectively alters the water supply. ATSDR was not able to evaluate the cost/benefit of these different options; therefore, it is up to the individual homeowners and the city and county officials to determine the best course of action.

  7. Comment: [Summarized and paraphrased] Representatives refused to release specific locations of resident complaints at the 9/4/02 meeting, yet released their report to the media in advance of the meeting. This may have driven down property values for the 25 homes identified in the report. Also, what about the 100 homes in the immediate vicinity that are served by well water?
  8. Response: Addresses of residents are confidential information. ATSDR did not release the report to the media in advance of the meeting; ATSDR released a press notice to be included in all local newspapers - this was intended for the media and the public. Once the problem at Cady Road is addressed, any decreased property values will return to normal or increase. ATSDR was not able to study all the homes with well water. We were asked specifically to look at Cady Road. This was a well-defined area of homes using well water from what appears to be the same aquifer. ATSDR agrees that the extent of the problem needs to be defined, however, this is out of the scope of our agency. A recommendation referring to this issue has been added to the document.

  9. Comment: [Summarized and paraphrased] Do any current residents have the potential health problems addressed in their report?
  10. Response: ATSDR compiled the community health concerns from several sources (public availability sessions, affidavits and personal communication). ATSDR did not conduct a health survey and therefore can not tally the numbers of individuals that reported each symptom. Health concerns were summarized based on public meetings, a public availability session, written affidavits, and personal communication. About 20 individuals expressed concerns about water quality and odors, about 15 individuals expressed concerns about water quality and not specifically odors, and about 7 individuals specifically expressed concerns about health.

  11. Comment: [Summarized and paraphrased] Will ATSDR help defray the cost to residents on Cady Road if we are forced to put in city water?
  12. Response: ATSDR's responsibility is to provide federal, state, and local agencies with the information they need to make a decision regarding remediation to protect public health. ATSDR can not enforce recommendations; rather, we rely on state and local agencies to follow our recommendations.

  13. Comment: [Summarized and paraphrased] The report is biased, flawed, and incomplete. It is limited to residences with private well water on a ½ mile stretch of Cady Road. Much of the southern part of N. Royalton is utilizing well water from the same aquifer. The study was based on only 9 volunteers that might be biased because they have a water issue. The other residents with no well water problems didn't volunteer. If the problem was inherent with the aquifer, your agency would receive numerous complaints from residents pulling from the same aquifer. Your study failed to mention the location of the 9 homes.
  14. Response: ATSDR cannot give out the exact locations of the 9 homes for confidentiality reasons. We can only state that they are on Cady Road. Our study was not meant to be statistically significant; rather it was intended to fill a data gap and to determine if people are being exposed to anything harmful in their drinking water. All residents on Cady Road had the opportunity to participate in our sampling event. ATSDR agrees that the extent of the problem should be determined.

  15. Comment: [Summarized and paraphrased] Testing conducted by CCBH, ODNR, and OHEPA found no chemicals at levels of health concern. Air samples gathered by the N. Royalton Fire Dept and another agency did not reveal combustible gas at levels of any concern.
  16. Response: Past sampling focused mainly on drinking water parameters: metals, VOCs and SVOCs. Although ATSDR also sampled for these, we also sampled for compounds that do not fall within drinking water parameters. Methane and hydrogen sulfide are two examples. Although these compounds do not have drinking water standards, they may still cause health effects. Additionally, ATSDR sampled during water usage. This more accurately defines how people would be exposed in the home.

  17. Comment: [Summarized and paraphrased] Methane gas can be easily removed from well water using an aeration process, but your study failed to mention this. Vented well heads are often enough to remove methane from well water.
  18. Response: Please see the response to comment 41 and 48.

  19. Comment: [Summarized and paraphrased] Your study presents no health data (statistics) about residents.
  20. Response: Please see the response to comment 82.

  21. Comment: [Summarized and paraphrased] My conclusion is that wells to the west of the fault line do not experience the water quality issues you describe.
  22. Response: From what ATSDR can tell from materials given to us by ODNR, we sampled homes on both sides of the fault line. The homes with the highest levels of methane do seem to be clustered. ATSDR did not sample enough homes to be able to conclude that the problem lies only with a certain section of the road.

  23. Comment: [Summarized and paraphrased] The naturally occurring hydrogen sulfide data is blown way out of proportion and was gathered at worst case conditions. Even at worst case, hydrogen sulfide effects would only come into play with someone of extreme chemical sensitivity exposed almost continuously.
  24. Response: ATSDR's Toxicological Profile on Hydrogen Sulfide discusses the health effects of exposure to hydrogen sulfide. Certain populations are especially susceptible to the effects of hydrogen sulfide such as asthmatics, those with respiratory conditions, children, and the elderly. These health effects, such as respiratory distress, have been observed for exposure periods as short as 30 minutes. The long term or chronic effects of hydrogen sulfide on humans is unknown. The hydrogen sulfide levels were recorded during water sampling, and represent realistic exposure scenarios. Also, as noted previously, it is just as likely that concentrations would fluctuate to levels higher than were detected by ATSDR during the exposure investigation as it is that the levels would actually be lower than what was detected.

  25. Comment: [Summarized and paraphrased] All residents with a Cady Road address should not be lumped into the same category. I live on Cady Road, but do not experience any problems with my well water.
  26. Response: Comment noted. Since we do not know the extent of contamination, our conclusions and recommendations apply to all Cady Road residents. However, ATSDR agrees that there may be special circumstances that make the wells on Cady Road differ by geology or geography.


Table of Contents

 
 
USA.gov: The U.S. Government's Official Web PortalDepartment of Health and Human Services
Agency for Toxic Substances and Disease Registry, 4770 Buford Hwy NE, Atlanta, GA 30341
Contact CDC: 800-232-4636 / TTY: 888-232-6348

A-Z Index

  1. A
  2. B
  3. C
  4. D
  5. E
  6. F
  7. G
  8. H
  9. I
  10. J
  11. K
  12. L
  13. M
  14. N
  15. O
  16. P
  17. Q
  18. R
  19. S
  20. T
  21. U
  22. V
  23. W
  24. X
  25. Y
  26. Z
  27. #