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Comparison values represent media-specific contaminant concentrations that are used to select contaminants for further evaluation to determine the possibility of adverse public health effects. The conclusion that a contaminant exceeds the comparison value does not mean that it will cause adverse health effects.

Cancer Risk Evaluation Guides (CREGs)
CREGS are estimated contaminant concentrations that would be expected to cause no more than one excess cancer in a million (10-6) persons exposed over their lifetime. ATSDR's CREGs are calculated from EPA's cancer potency factors (CPFs).

Maximum Contaminant Level (MCL)
The MCL is the drinking water standard established by EPA. It is the maximum permissible level of a contaminant in water that is delivered to the free-flowing outlet. MCLs are considered protective of public health over a lifetime (70 years) for individuals consuming 2 liters of water per day.

Environmental Media Evaluation Guides (EMEGs)
EMEGs are based on ATSDR minimal risk levels (MRLs) that consider body weight and ingestion rates. An EMEG is an estimate of daily human exposure to a chemical (in mg/kg/day) that is likely to be without noncarcinogenic health effects over a specified duration of exposure to include acute, intermediate, and chronic exposures.

Reference Media Evaluation Guides (RMEGs)
ATSDR derives RMEGs from EPA's oral reference doses. The RMEG represents the concentration in water or soil at which daily human exposure is unlikely to result in adverse noncarcinogenic effects.


Background Level:
An average or expected amount of a chemical in a specific environment. Or, amounts of chemicals that occur naturally in a specific-environment.

Comparison Values:
Concentrations or the amount of substances in air, water, food, and soil that are unlikely, upon exposure, to cause adverse health effects. Comparison values are used by health assessors to select which substances and environmental media (air, water, food and soil) need additional evaluation while health concerns or effects are investigated.

How much or the amount of a substance present in a certain amount of soil, water, air, or food.

The amount of a substance to which a person may be exposed, usually on a daily basis. Dose is often explained as "amount of substance(s) per body weight per day".

Environmental Contaminant:
A substance (chemical) that gets into a system (person, animal, or the environment) in amounts higher than that found in Background Level, or what would be expected.

Environmental Contamination:
The presence of hazardous substances in the environment. From the public health perspective, environmental contamination is addressed when it potentially affects the health and quality of life of people living and working near the contamination.

U.S. Environmental Protection Agency (EPA):
The federal agency that develops and enforces environmental laws to protect the environment and the public's health.

Coming into contact with a chemical substance.(For the three ways people can come in contact with substances, see Route of Exposure.)

Swallowing something, as in eating or drinking. It is a way a chemical can enter your body (See Route of Exposure).

Soil, water, air, plants, animals, or any other parts of the environment that can contain contaminants.

Minimal Risk Level (MRL):
An estimate of daily human exposure - by a specified route and length of time -- to a dose of chemical that is likely to be without a measurable risk of adverse, noncancerous effects. An MRL should not be used as a predictor of adverse health effects.

National Priorities List (NPL):
The National Priorities List. (Which is part of Superfund.) A list kept by the U.S. Environmental Protection Agency (EPA) of the most serious, uncontrolled or abandoned hazardous waste sites in the country. An NPL site needs to be cleaned up or is being looked at to see if people can be exposed to chemicals from the site.

No Apparent Public Health Hazard:
The category is used in ATSDR's Public Health Assessment documents for sites where exposure to site-related chemicals may have occurred in the past or is still occurring but the exposures are not at levels expected to cause adverse health effects.

No Public Health Hazard:
The category is used in ATSDR's Public Health Assessment documents for sites where there is evidence of an absence of exposure to site-related chemicals.

Parts per Billion (ppb)/ Parts per Million (ppm):
Units commonly used to express low concentrations of contaminants. As example of each, one part per billion (ppb) of trichloroethylene (TCE) equals one drop of TCE mixed in a competition-size swimming pool and one part per million (ppm) equals one ounce of trichloroethylene (TCE) in one million ounces of water.

Potentially Exposed:
The condition where valid information, usually analytical environmental data, indicates the presence of contaminant(s) of a public health concern in one or more environmental media contacting humans (i.e., air, drinking water, soil, food chain, surface water), and there is evidence that some of those persons have an identified route(s) of exposure (i.e., drinking contaminated water, breathing contaminated air, having contact with contaminated soil, or eating contaminated food).

Public Health Assessment:
A report or document that looks at chemicals at a hazardous waste site and tells if people could be harmed from coming into contact with those chemicals. The PHA also tells if possible further public health actions are needed.

Public Health Hazard:
Sites that pose a public health hazard as the result of long-term exposures to hazardous substances.

Reference Dose (RfD):
An estimate, with safety factors (see safety factor) built in, of the daily, life-time exposure of human populations to a possible hazard that is not likely to cause harm to the person.

Route of Exposure:
The way a chemical can get into a person's body. There are three exposure routes:
    - breathing (also called inhalation),
    - eating or drinking (also called ingestion), and
    - or getting something on the skin (also called dermal contact).

Safety Factor:
Also called Uncertainty Factor. When scientists don't have enough information to decide if an exposure will cause harm to people, they use "safety factors" and formulas in place of the information that is not known. These factors and formulas can help determine the amount of a chemical that is not likely to cause harm to people.

Volatile organic compounds (VOCs):
Substances containing carbon and different proportions of other elements such as hydrogen, oxygen, fluorine, chlorine, bromine, sulfur, or nitrogen; these substances easily become vapors or gases. A significant number of the VOCs are commonly used as solvents (paint thinners, lacquer thinner, degreasers, and dry cleaning fluids).


Estimates of Human Exposure Doses and Determination of Health Effects

Deriving Exposures Doses

The Agency for Toxic Substances and Disease Registry (ATSDR) typically evaluates the publichealth implications of exposure by considering the contaminant's chemical class, concentration ofthe contaminants to which people may have been exposed, and how often and how long exposure tothese contaminants occurred. Together, these factors help influence the individual's response tochemical exposure and potential noncancer and cancer outcomes. ATSDR estimated the humanexposure doses from ingestion of water containing volatile organic compounds (VOCs) from thesupply wells at LCAAP and from off-site private wells north of LCAAP. In the absence of completeexposure-specific information, ATSDR applied several conservative exposure assumptions to definesite-specific exposures as accurately as possible for workers and visitors to the plant, the smallnumber of adults and children living at the housing area, and individuals who drink water from off-site private wells.

Evaluating Potential Health Hazards

The estimated exposure doses are used to evaluate potential noncancer and cancer effects associatedwith chemicals of concern. When evaluating noncancer effects, ATSDR uses standard toxicityvalues, including ATSDR's minimal risk levels (MRLs) and EPA's reference doses (RfDs) todetermine whether adverse effects are likely to occur. The chronic MRLs and RfDs are estimates ofdaily human exposure to a substance that are unlikely to result in adverse noncancer effects over aspecified duration. To be very protective of human health, MRLs and RfDs have built in"uncertainty" or "safety" factors that make them much lower than levels at which health effects havebeen observed. Therefore, if an exposure dose is much higher than the MRL or RfD, it does notnecessarily follow that adverse health effects will occur.

When evaluating cancer effects, ATSDR sometimes uses cancer potency factors (CPFs) that definethe relationship between oral exposure doses and the increased likelihood of developing cancer overa lifetime. The CPFs are developed using data from animal or human studies and often requireextrapolation from high exposure doses administered in animal studies to the lower exposure levelstypical of human exposure to environmental contaminants. CPFs represent the upper-bound estimateof the probability of developing cancer at a defined level of exposure; therefore, they tend to be veryconservative (i.e., overestimate the actual risk) in order to account for a number of uncertainties inthe data used in the extrapolation. ATSDR estimated the potential for cancer to occur using thefollowing equation (The estimated exposure doses and CPF values for the contaminants of concern are incorporated into the equation):

Lifetime Cancer Risk = Estimated exposure dose (mg/kg/day) x CPF (mg/kg/day)-1

Although no risk of cancer is considered acceptable, it is impossible to achieve a zero cancer risk. Consequently, ATSDR often uses a range of 10-4 to 10-6 estimated lifetime cancer risk (or 1 new case in 10,000 to 1,000,000 exposed persons), based on conservative assumptions about exposure, to determine the likelihood of excess cancer resulting from this exposure.

In addition to estimating the likelihood of noncancer and cancer effects, ATSDR reviewed theliterature to evaluate possible health effects associated with exposure at the doses/concentrationsestimated for the pathway described below.

Estimated Exposure Dose for Consumption of VOCs in Drinking Water

In estimating to what extent people might be exposed to VOCs, ATSDR used the following equationand applied "conservative" or safe assumptions about possible human exposure. ATSDR assumedthat a person drank the most contaminated well water. ATSDR also used conservative assumptionsabout how often people drink water and how much they drink. These assumptions allow ATSDR toestimate the highest possible exposure dose and determine the corresponding health effects.Although ATSDR expects that few individuals, if any, were exposed to the highest levels ofcontamination, the "conservative" estimates are used to protect public health. The followingdescribes the equation and assumptions used to estimate the exposure:

mathematical equation

Conc.: Maximum concentration of VOCs in the well water (ppb)
CF: Conversion factor to convert ppb to parts per million (1/1,000)
IR: Ingestion rate: adult=2 liters per day; child=1 liter per day
EF: Exposure frequency or number of exposure events per year of exposure: 7 days/week x 52 weeks/year
ED: Exposure duration or the duration over which exposure occurs: adult=30 years; child=6 years
BW: Body weight: adult=70 kg (154 pounds); child=10 kg (22 pounds)
AT: Averaging time or the period over which cumulative exposures are averaged (6 or 30 years x 365 days/year for noncancer effects or 70 years for cancer)

The estimated exposure doses are expected to be very conservative values because they are based on the following assumptions.

  • ATSDR estimates that an adult drank 2 liters and a child drank 1 liter of water a day and that all drinking water came from the supply wells at LCAAP. This assumption likely leads to an overestimate of the actual exposure dose because individuals most likely drank water from other sources.

  • The exposure frequency (EF), or number of exposure events per year, was assumed to be365 days per year, based on a 7-day-a-week exposure over 52 weeks per year. Thismaximum exposure frequency would only pertain to the small number of individuals wholived on site at the time that the supply wells were used as a drinking water source for the housing area. Workers at LCAAP would have a much shorter exposure frequency.

  • The duration of exposure (ED) is assumed to have occurred over a 30-year period foradults. For a child, ATSDR used a 6-year exposure duration.

  • The maximum concentration of contaminants detected in any of the supply wells was used. It is extremely unlikely that anyone would be exposed at these levels because water from all 13 supply wells is blended prior to distribution.

Past Exposures from the On-Site Drinking Water Supply at LCAAP

VOCs in four supply wells (17-AA, 17-FF [no longer used for drinking water], 17-K, and 17-P) atLCAAP exceeded ATSDR's health-based comparison values (CVs) for drinking water in the past.To determine whether past exposure to these contaminants in the plant's drinking water supply mayhave caused adverse health effects, ATSDR estimated exposure doses for people consuming watercontaining the highest measured concentrations detected in the wells. The estimated exposure doseswere then used to evaluate potential noncancer and cancer outcomes.

Noncancer: ATSDR estimated exposure doses from ingestion of water from the LCAAP supplywells containing trichloroethylene (TCE), tetrachloroethylene (PCE), 1,2-dichloroethene, and vinylchloride (see Table C-1). No chronic (365 days and longer) oral MRL or RfD is currently availablefor TCE. ATSDR also recently withdrew the intermediate (15-364 days) MRL for TCE. The studyon which the intermediate MRL was based has been questioned because it contains certain flaws andlimitations (e.g., the exact amount of TCE-contaminated water consumed by laboratory animals inthe study is uncertain) (ATSDR 1997c).

In the absence of health-based guidelines, ATSDR reviewed the available toxicological literature to determine possible adverse effects associated with exposure at doses estimated for this pathway. On the basis of this review, the exposure doses estimated for TCE by ATSDR are several orders of magnitude lower than the lowest doses reported in the toxicological literature capable of producing noncancer effects in animals administered oral doses of TCE (ATSDR 1997c). Therefore, drinking water containing the highest detected levels of TCE reported in on-site supply wells at LCAAP is not likely to result in adverse noncancer effects.

The resulting estimated exposure dose for PCE (adults and children) and the exposure dose for 1,2-DCE (adults) are lower than their RfD. Exposures to these two chemicals at the levels detectedshould not be associated with adverse health effects. The exposure dose for 1,2-DCE for children isslightly higher than its RfD of 0.02 mg/kg/day, but the slightly higher dose is not of healthconsequence because the exposure doses estimated for 1,2-DCE by ATSDR are several orders ofmagnitude lower than the lowest doses reported in the toxicological literature capable of producingnoncancer effects in animals administered oral doses of 1,2-DCE.

The estimated exposure dose for vinyl chloride, for both adults and children, is higher than its MRLof 0.00002 mg/kg/day. A review of the literature shows that the lowest dose of vinyl chloride inwhich noncancer effects were observed involved a chronic exposure animal study. This study foundslight changes in cellular structure after animals were fed 0.02 mg/kg/day of polyvinylchloridepowder for approximately 3 years. For most other studies, the lowest observed adverse effect level(LOAEL) was two orders of magnitude (i.e., 2.0 mg/kg/day) greater than the 0.02 mg/kg/day dose(ATSDR 1997d). Using the most conservative assumptions, the maximum estimated dose for a childwas 0.03 mg/kg/day, which is in the range of the LOAEL reviewed in the literature.

Although the estimated dose for vinyl chloride (adult and child) exceeded ATSDR's MRL, it isunlikely that individuals who consumed the drinking water from LCAAP were exposed to harmfullevels of this contaminant. The estimated doses of vinyl chloride were based on the maximumconcentration detected (270 ppb) in one supply well, but it is not expected that anyone drank watercontaining that concentration. (The average level of vinyl chloride from this supply well was muchlower [125 ppb] (Dames & Moore 1999). This supply well was one of 13 wells used to supplyLCAAP with drinking water. Vinyl chloride was only detected in three of 13 supply wells. It is alsoimportant to note that water from the 13 supply wells is mixed and blended in a large (500,000gallon) holding tank and no one at LCAAP is drinking water from one supply well. Therefore, it isalmost certain that levels of vinyl chloride and 1,2-DCE in the finished water supply would havebeen much lower than the maximum concentrations used to estimate doses.

In addition, ATSDR assumed that individuals at LCAAP were drinking water from LCAAP 365days a year. However, it is unlikely that any individual obtained their drinking water exclusivelyfrom one source. According to LCAAP representatives, individuals who have lived in the on-sitehousing area usually only do so for a short time, perhaps 3 or 4 years. The estimated dose calculatedassumed that individuals were being exposed for 30 years.

For the reasons described above, ATSDR concludes that ingestion of TCE, PCE, 1,2-DCE, andvinyl chloride, from the LCAAP water supply in the past is not expected to have resulted in adversehealth effects.

Cancer: TCE and PCE have been shown to cause cancer in laboratory animals given large doses. The link between TCE and cancer in humans is uncertain, however. Available studies are inconclusive and the data are inadequate to establish a link. For screening purposes ATSDR used a previously derived CPF for TCE of 0.011 (mg/kg/day)-1 and for PCE of 0.052 (mg/kg/day)-1. The slope factors for these chemicals are under review. ATSDR derived cancer risk estimates for exposure to TCE and PCE that fall within the range (less than 10-5) considered acceptable. On the basis of these results, ATSDR concludes that ingestion of either TCE or PCE at the levels detected in the on-site well water is not likely to result in an increased risk of developing cancer (see Table C-2).

No studies were identified regarding cancer in humans following oral exposure to vinyl chloride.There currently is no CPF for vinyl chloride based on human studies, however, there is strongevidence from inhalation studies in humans and inhalation and oral studies in animals to suggest thatit is a carcinogen. EPA has concluded that sufficient evidence of carcinogenicity exists in humansand has classified vinyl chloride as a Group A (human) carcinogen. A large number of studies havereported a greater than expected incidence of a rare type of cancer, angiosarcoma of the liver, amongworkers exposed to vinyl chloride (ATSDR 1997d). Chronic oral studies found an increase in liverangiosarcoma in animals fed 0.3 mg/kg/day (ATSDR 1997d). The maximum exposure doseestimated for an adult consuming water from LCAAP is about two orders of magnitude lower thanthat found to increase liver tumors in animals. Based on this information and the very conservativeexposure assumptions used, ATSDR does not expect that ingestion of vinyl chloride from theLCAAP water supply would result in an increased likelihood of developing cancer.

Off-Site Private Wells

Three VOCs were detected above CVs during LCAAP's monitoring of 12 residential wellsconducted from July 1988 through September 1993. Benzene (1.1 ppb), TCE (6.4 ppb), and 1,1-DCE (2 ppb) were detected at levels slightly above their CVs. With the exception of TCE, whichwas detected twice above its CV, the other two chemicals were only detected one time above theirCVs during the entire monitoring period.

Noncancer: ATSDR estimated exposure doses from ingestion of water from the off-site privatewells for benzene, TCE, and 1,1-DCE (see Table C-3). An RfD or MRL was available for 1,1-DCE,but was not available for benzene and TCE.

ATSDR's review of the literature shows that the lowest no observed adverse effect level for benzenein animal studies was 1 mg/kg/day (ATSDR 1997a). The maximum estimated exposure for benzenefor a child in private wells was about four orders of magnitude lower than what was observed in anyof the studies identified. The exposure doses estimated for TCE by ATSDR are five orders ofmagnitude lower than the lowest doses reported in the toxicological literature capable of producingnoncancer effects in animals administered oral doses of TCE (ATSDR 1997c). For 1,1-DCE, theestimated dose was lower than the RfD reported in Table C-3. Based on the maximum estimateddose and a review of the toxicologic literature, ATSDR concludes that ingestion of benzene, TCE, or1,1-DCE at the levels detected in off-site private wells is not expected to result in adverse healtheffects.

Cancer: ATSDR derived cancer risk estimates for exposure to benzene, 1,1-DCE, and TCE that fallwithin the range (less than 10-5) considered acceptable by ATSDR. ATSDR concludes that cancereffects are unlikely to be experienced as a result of drinking water drawn from the off-site wells (seeTable C-4).


Agency for Toxic Substances and Disease Registry (ATSDR). 1994. Toxicological Profile for 1,1-dichloroethene. Update. May 1994.

ATSDR. 1996. Toxicological Profile for 1,2-dichloroethene. Update. August 1996.

ATSDR. 1997a. Toxicological Profile for Benzene. Update. September 1997.

ATSDR. 1997b. Toxicological Profile for Tetrachloroethylene. Update. September 1997.

ATSDR. 1997c. Toxicological Profile for Trichloroethylene. Update. September 1997.

ATSDR. 1997d. Toxicological Profile for Vinyl Chloride. Update. September 1997.

Dames & Moore. 1999. 1998 Annual Report for LCAAP Comprehensive Groundwater Monitoring Program. August 1999.

Table C-1.

Estimated Exposure Doses--Noncancer Effects Ingestion of Drinking Water at LCAAP
Contaminant Maximum Detected Contaminant Concentration (ppb) Estimated Exposure Dose (mg/kg/day)a Health Guideline
Basis for Health Guideline
Adult Child


0.01 0.04 0.02 RfD


0.00005 0.0002 0.01 RfD


0.001 0.005 not available ----
Vinyl chloride


0.008 0.03 0.00002 MRL

mathematical equation

Conc. = Maximum contaminant concentration in on-site supply wells (ppb).
CF = Conversion factor to convert ppb to ppm (1/1000)
IR = Ingestion rate: adult = 2 liters per day; child = 1 liter per day
EF = Exposure frequency or the number of exposure events (7 days x 52 weeks or 365 days per year)
ED = Exposure duration or the duration over which exposure occurs: adults = 30 years; child = 6 years
BW = Body weight (kg): adult = 70 kg (154 pounds); child = 10 kg (22 pounds)
AT = Average time or the period over which cumulative exposures are averaged (6 or 30 years x 365 days)

Key: ppb = parts per billion; mg/kg/day=milligrams contaminant per kilogram body weight per day; MRL = ATSDR's minimal risk level; RfD= EPA's reference dose.

Table C-2.

Estimated Exposure Doses--Cancer Effects Ingestion of Drinking Water at LCAAP
Contaminant Maximum Contaminant Concentration (ppb) Estimated Exposure Dose (mg/kg/day) a Cancer Potency Factor
Lifetime Cancer Risk
Tetrachloroethylene 1.7 0.00002 0.052b 1 x 10 -6
Trichloroethylene 52 0.0006 0.011b 7 x 10 -6
Vinyl chloride 270 0.003 not available -----

mathematical equation

b These cancer potency factors are currently under review by EPA.

Conc. = Maximum contaminant concentration in the on-site supply wells (ppb)
CF = Conversion factor to convert ppb to ppm (1/1000)
IR = Ingestion rate: 2 liters per day
EF = Exposure frequency, or the number of exposure events ( 365 days per year)
ED = Exposure duration, or the duration over which exposure occurs = 30 years
BW = Body weight (kg): 70 kg (154 pounds)
AT = Average time or the time over which cumulative exposures are averaged (70 years x 365 days)

Key: ppb = parts per billion; mg/kg/day=milligrams contaminant per kilogram body weight per day.

Table C-3.

Estimated Exposure Doses--Noncancer Effects Ingestion of Drinking Water From Private Wells
Contaminant Maximum Detected Contaminant Concentration (ppb) Estimated Exposure Dose (mg/kg/day)a Health Guideline
Basis for Health Guideline
Adult Child


0.00003 0.0001 not available ----


0.00006 0.0002 0.02 RfD
Trichloroethylene (TCE)


0.0002 0.0006 not available ----

mathematical equation

Conc. = Maximum contaminant concentration in off-site private wells (ppb)
CF = Conversion factor to convert ppb to ppm (1/1000)
IR = Ingestion rate: adult = 2 liters per day; child = 1 liter per day
EF = Exposure frequency or the number of exposure events (365 days per year)
ED = Exposure duration or the duration over which exposure occurs: adults = 30 years; child = 6 years
BW = Body weight (kg): adult = 70 kg (154 pounds); child = 10 kg (22 pounds)
AT = Average time or the period over which cumulative exposures are averaged (6 or 30 years x 365 days)

Key: ppb = parts per billion; mg/kg/day=milligrams contaminant per kilogram body weight per day.

Table 1.

Estimated Exposure Doses--Cancer Effects Ingestion of Drinking Water From Private Wells
Contaminant Maximum Contaminant Concentration (ppb) Estimated Exposure Dose (mg/kg/day) a Cancer Potency Factor
Lifetime Cancer Risk


0.00001 0.029 4 x 10 -7


0.00002 0.6 1 x 10 -5


0.00008 0.011b 8 x 10 -7

mathematical equation

b These cancer potency factors are currently under review by EPA.

Conc. = Maximum contaminant concentration in off-site private wells (ppb)
CF = Conversion factor to convert ppb to ppm (1/1000)
IR = Ingestion rate: 2 liters per day
EF = Exposure frequency, or the number of exposure events (1 event x 7 days x 52 weeks or 365 days per year)
ED = Exposure duration, or the duration over which exposure occurs = 30 years
BW = Body weight (kg): 70 kg (154 pounds)
AT = Average time or the time over which cumulative exposures are averaged (70 years x 365 days)

Key: ppb = parts per billion; mg/kg/day=milligrams contaminant per kilogram body weight per day.


The Public Health Assessment (PHA) for Lake City Army Ammunition Plant (LCAAP) wasavailable for public review and comment from October 3, 2000 through November 22, 2000. Thepublic comment period was announced in a press release on October 4, 2000. Copies of the publichealth assessment were made available for review at the Mid-continent Public Library, BlueSprings, Missouri and the LCAAP information repository. The PHA was also sent to state andfederal agencies for review. Upon request from LCAAP officials, ATSDR extended the publiccomment period until July 26, 2001 so that comments received from the July 26, 2001 publicavailability session could be incorporated into the final release document.

The following are responses to EPAs comments pertaining to ATSDRs Public Comment Release.

Comment 1: In general, we disagree with your conclusions regarding the prospects ofpublic health hazards associated with past, current, or future exposures to releases ofhazardous substances from the LCAAP. Regarding past exposures, we do not believesufficient data is available to determine whether potentially negative health impactsassociated with past exposures may have occurred. Further, we do not agree thatconditions at the site are currently adequately controlled such that potential exposures(and associated health impacts) will likely not occur in the future. Given site conditions, inthe absence of further response actions by the Army, we believe it highly possible thatsignificant exposures to hazardous substances could occur. We also believe that land useat the LCAAP may be subject to significant changes in the short term, based on what theArmy terms its' "facilities use" approach. Such changes in land use could dramaticallyalter the nature of potential exposures and subsequent health risks.

Response: ATSDR acknowledges EPAs difference in opinion regarding the conclusionscontained in the PHA. In the process of conducting a public health assessment (PHA), ATSDRevaluates whether a completed exposure pathway has occurred in the past, is occurringcurrently, or is likely to occur in the future. When a completed pathway has been identified,ATSDR evaluates whether exposures are at levels that would contribute to adverse healtheffects. ATSDR recognizes that some hazardous contamination generated from activities atLCAAP continues to be present on site. However, ATSDR bases its public health conclusionsnot only on whether contamination is present, but also on whether it is likely that people will come in contact with levels of contaminants that may be harmful. Based on the available datathat was provided to ATSDR, there is no evidence of past, current, or future public healthhazards. ATSDR agrees that continued monitoring of groundwater plumes beneath LCAAP isnecessary to make sure that off-site migration is not taking place.

Comment 2: Page 1, Summary, Paragraph 5 - We suggest you consult with theArmy/LCAAP regarding the schedule for completing a ROD for the Installation-Wide OU. It may be appropriate to provide more specific information regarding the anticipated RODdate for this OU.

Response: According to information provided by LCAAP representatives, an InterimRemedial Action ROD for metals contaminated soil for the Installation-wide OU is scheduledto be signed in the Fall 2001. LCAAP is still working on a schedule for releasing a final RODfor the Installation-wide OU, which will include both remediation of non-metal contaminantsin soil and groundwater.

Comment 3: Page 2, Summary, Paragraph 4 - The PHA should indicate the basis forconcluding that exposures to contaminants in private wells pose no apparent past, current,or future public health threat. In the absence of continued and/or additional responseactions by the Army, the prospects for exposures and health threats are quite likely in thefuture.

Response: In evaluating the potential for past, current, and future health effects from drinkingwater, ATSDR estimated the lifetime exposure dose for both an adult and a child who drinkwater containing the maximum concentration of the chemical detected in either on-site supplywells at LCAAP or off-site private drinking water wells located north of LCAAP. Appendix Cin the PHA provides a complete description of the methods and assumptions ATSDR used toestimate exposure. As explained in Appendix C, the dose estimates calculated are based onvery conservative assumptions that have built in safety factors. ATSDR recognizes that theremay be some exposure to contaminants in drinking water, however, the concentrations thathave been detected in off-site private wells and in the LCAAP drinking water supply wells arenot at levels considered to pose a health hazard. This evaluation is based on toxicologicalprofiles of the chemicals detected in the drinking water.

ATSDR has recommended that LCAAP resume routine monitoring of private wells north ofthe Area 18 and Northeast Corner OU. According to LCAAP representatives, this monitoringis scheduled to be resumed in the spring/summer 2001 (personal communication with GarthAnderson, March 5, 2001).

Comment 4: Page 2, Summary, Paragraph 5 - The PHA should indicate the basis for theconclusions presented here, to clarify the assumptions regarding possible land use atLCAAP.

Response: ATSDR concluded that on-site soil and surface water contamination did not pose apast or does not pose a current or future public health hazard because access to LCAAP isrestricted and sampling has indicated that most soil and surface water contamination isgenerally confined to areas near the source with no evidence of migration off site. UnderLCAAP's "facility use" plan, any new land use must be reviewed by LCAAP and theOperations Support Command. Any proposed reuse of land must meet existing legalagreements and conditions , including land use restrictions and institutional controls agreedupon by LCAAP.

Comment 5: Page 3, Summary, Paragraph 2 - We believe this paragraph accurately statesthat "...there are not data to evaluate whether contaminants released into the air werepresent at levels that were harmful...". Based on this statement, it is unclear how youconclude that past exposures presented minimal health threats when insufficient data isavailable to support this conclusion.

Response: ATSDR must often rely on limited information when evaluating past publichealth hazards. When activities or operations at a site are known to have resulted in some pastenvironmental contamination (e.g., groundwater or air), ATSDR first identifies and reviewswhatever historical monitoring data is available. In cases where no monitoring data isavailable, ATSDR collects as much information about the nature and extent of releases intothe environment.

Based on correspondence with LCAAP officials, open burning activities took place atdesignated open burn areas, primarily in the northeastern portion of the plant, approximatelyonce a week as long as certain weather conditions were met. Open burns were conductedunder certain weather conditions to prevent or minimize smoke and air particulates fromimpacting off-site residents.

According to historical information from LCAAP, approximately 300 pounds of primarilypropellant and wet explosive scrap were burned per week. This amount was significantlybelow the LCAAP permit allowing for up to 240 pounds per day or a maximum of 1,440pounds per week. Open burning activities were significantly reduced after the explosive wasteincinerator was brought up to incinerator standards in 1989. Open burning activities were nolonger conducted at LCAAP after 1993.

Based on the relative infrequency of open burns, the precautionary measures taken to preventsmoke and air particulates from impacting residents, and the very small number of residencesnorth of LCAAP, ATSDR concludes that past exposures would not likely pose a healthhazard. Although monitoring data is not available for these past activities, ATSDR has basedthis public health conclusion on the best available information.

Comment 6: Page 5, Background, Paragraph 2 - Alliant Techsystems is the currentoperating contractor for the LCAAP, assuming operations from Olin in April 2000. Wesuggest you confer with the LCAAP to ensure accurate information in this paragraph.

Response: ATSDR has confirmed with LCAAP that Alliant Techsystems is the currentoperating contractor and this will be reflected in the final PHA.

Comment 7: Page 7, Background, Paragraph 2 - Suggest that the text be revised to reflectthat the Remedial Investigation for the Northeast Corner OU is still in progress. Suggestthat a more specific date for the Installation-Wide OU ROD be provided.

Response: ATSDR has received updated information concerning the status of the remedialinvestigation for the Northeast Corner OU and this will be reflected in the final PHA.According to an LCAAP representative, the release date for the Installation-Wide OU ROD isstill under negotiation.

Comment 8: Page 10, QA/QC - Suggest you briefly discuss the evaluation processemployed to determine the adequacy of the available data for making public healthdecisions.

Response: As noted in the PHA, reports that are prepared for the ComprehensiveEnvironmental Response, Compensation, and Liability Act and the Resource Conservationand Recovery Act programs must meet specific standards for quality assurance and qualitycontrol. In addition to this, ATSDR reviews data from site-related reports and evaluateswhether detection limits are set at levels that are protective of public health. ATSDR also notesany inconsistencies or problems with data collection or reporting and evaluates whether theinformation is adequate to be used for making public health decisions. ATSDR will make thesuggested changes noted above.

Comment 9: Page 12, Conclusions - We believe insufficient information is available todetermine the nature of possible past exposures/health hazards associated withgroundwater at/from LCAAP.

The PHA should clarify that the presence of drinking water of acceptable quality at LCAAPis predicated on the continued operations, maintenance, and monitoring of existing watertreatment operations.

The PHA should clarify that the prevention of future exposures to contaminants ingroundwater beyond LCAAP boundaries is predicated on continued operations,maintenance, and monitoring of existing response actions, and the implementation ofadditional actions to control releases of hazardous substances at the LCAAP.

Please correct the last paragraph to indicate that contaminants are present ingroundwater at the northern plant boundary at levels above (order of magnitude) thatwhich would pose a health threat if consumed regularly. It should be clarified that thiscontamination has likely migrated beyond the plant boundary, but that the nature andextent of the off-plant contamination has not been completely defined. Also, please notethe presence of a groundwater contaminant plume in the western part of LCAAP, which haspotential to migrate off-plant.

Response: As noted above, ATSDR estimated the dose, for both an adult and a child, ofchemicals detected in drinking water wells above ATSDRs CVs. ATSDR used the maximumconcentration detected in supply wells at LCAAP in order to provide a worst case scenario.Appendix C in the PHA explains the assumptions used in calculating an individual's exposuredose.

ATSDR will modify the text of the PHA to include a statement that clarifies that the safety ofindividuals consuming drinking water at LCAAP relies on continued water treatment androutine monitoring of the drinking water supply.

In response to the last paragraph of comment # 9, the statement on page 12 of the PHAspecifically refers to contaminants detected in off-site drinking water wells. Although VOCsand metals were detected in some of these wells, the concentrations were not at levels that posea public health hazard. VOCs were detected in untreated LCAAP drinking water supply wells[17KK (TCE-3.6 ppb) and 17K (TCE-1.5 ppb)] and in monitoring wells [16-18 (1,2-Dichloroethene-10.7 ppb); TCE-13.9 ppb)] near the northern plant boundary during 1999.However, groundwater sampling of supply wells and monitoring wells near the northernboundary showed a declining trend in VOC concentrations compared to 1998 data. ATSDRwill clarify that contamination has the potential to migrate beyond the plant boundary and thatit is important for LCAAP to characterize the nature and extent of contamination north ofLCAAP. ATSDR will also clarify that the nature and extent of the groundwater plume in thewestern portion of the plant should also be characterized due to the potential for it to migrateoff site.

Comment 10: Page 13, Physical Characteristics - The notion of "hydrostratigraphicunits" is not truly a physical feature, but one defined for purposes of modeling, primarily. It may be appropriate to edit or simplify much of this discussion.

Response: ATSDR will note in the text that hydrostratigraphic units are not actual physicalhydrogeological features, but were developed to help conceptualize how groundwater flowsunderneath LCAAP. ATSDR will consider clarifying or simplifying any discussion in thissection where appropriate.

Comment 11: Page 15, On-Site Groundwater Contamination, Paragraph 1 - The PHAshould consider that results of sampling from water supply wells may not be representativeof aquifer/groundwater conditions. Given the dilution that will occur in a water supplywell, unlike in a groundwater monitoring well, groundwater contamination may be muchmore significant than the sampling results indicate.

Response: As noted previously, ATSDR identifies whether a completed exposure pathwayexists. If a completed pathway is identified, ATSDR evaluates whether this exposure is likelyto cause adverse health outcomes using very conservative assumptions (e.g., estimating doseusing the maximum concentration detected in drinking water supply wells).

Regardless of the levels of contamination detected in groundwater or any other environmentalmedia, it is important to emphasize that a public health hazard exists only if people come incontact with or are exposed to harmful levels of contaminants. ATSDR evaluated the potentialfor treated drinking water at LCAAP to contain harmful levels of chemicals. Routinemonitoring of the LCAAP drinking water supply has confirmed that the treated water that isused for drinking at LCAAP meets state and federal drinking water standards. ATSDR has notidentified any individuals at LCAAP that are drinking water from untreated groundwatersources and, therefore, people are not being exposed to levels of contamination that would beharmful.

Comment 12: Page 16, On-Site Groundwater Contamination, Paragraph 2 - The PHAshould indicate that groundwater contamination extends to, and likely beyond, thenorthern boundary of the LCAAP.

Response: ATSDR will add that the nature and extent of contamination beyond the northernplant boundary has yet to be determined and it is possible that groundwater contamination hasmigrated off site.

Comment 13: Page 18, Off-Site Groundwater Contamination, Paragraph 1 - The PHAstates, based on a personal communication, that LCAAP groundwater extraction wellsprevent most off-site migration. In terms of protectiveness, there could be a significantdifference between preventing most and all off-site contaminant migration. We suggestthat you supplement this personal communication with evaluation of existing records orassessments which address the effectiveness of the extraction wells in containinggroundwater contamination, and that you clarify what is meant by the statement that mostoff-site migration is prevented.

Response: Although there may be some migration of the Area 18 and Northeast Corner OUcontaminant plume, according to the 1999 Annual Report for LCAAP GroundwaterMonitoring Program, which presents data from 1988 through 1999, the monitoring wellslocated on the northern perimeter have generally shown decreasing trends in contaminantlevels. For example, in Monitoring Well 16-17, TCE levels in groundwater have decreasedfrom 57 ppb in 1996 to 13.9 ppb in 1999.

ATSDR cannot definitively say that all off-site contaminant migration has been preventedsince the nature and extent of the plume needs to be further delineated. However, based ontoxicological profiles of TCE and other contaminants identified in these monitoring wells,even if people were currently exposed to the maximum concentrations that are present innorthern boundary monitoring wells, such exposures would not be harmful.ATSDR expectsthat site-related contaminants would either not be detected or detected at much lowerconcentrations in the closest private wells north of LCAAP. Because the plume needs to bebetter defined, however, ATSDR has recommended that quarterly monitoring of private wellsnorth of LCAAP be reinstated.

Comment 14: Page 18, Off-Site Groundwater Contamination, Paragraph 2 - The PHAstates, based on a personal communication, that the presence of lead and cadmium mayhave been an "artifact". Since the notion of the contamination being an "artifact" isinterpretive and not necessarily supported by facts, we suggest you remove this statement.

Response: This statement has been removed and the paragraph has been revised.

Comment 15: Page 20, Current and Future Exposures, On-site - The PHA should clarifythat the water supply (i.e. aquifer) has not necessarily met drinking water standards, butthat the treated water, prior to consumption, has met drinking water standards. It isimportant to highlight that a continuing treatment process is required for drinking water atthe LCAAP to meet protective standards.

Response: This distinction will be clarified in the text of the PHA.

Comment 16: Page 20, Current and Future Exposures, Off-site - While the operation of thegroundwater extraction well at the northern LCAAP boundary may prevent furthermigration of contaminants in groundwater off-plant, the nature and potential impacts ofcontamination which may have migrated off-plant prior to the installation of the extractionwell is unknown.

Response: Because of the uncertainty regarding the nature and extent of groundwatercontamination north of LCAAPs Area 18 and the Northeast Corner OU, ATSDR hasrecommended in the PHA that quarterly monitoring of private wells be reinstated.

Comment 17: Page 22, Evaluation of the Soil Exposure Pathway, Conclusion - Remedialactions have not yet been planned or implemented which will address all areas ofcontamination which may pose an unacceptable risk at the LCAAP.

Response: ATSDR will confirm with LCAAP which areas of soil contamination at LCAAPhave not been addressed, either through planned or past remediation or through other interimmeasures.

Comment 18: Page 23, Northeast Corner OU, Paragraph 1 - The PHA refers to a "finalROD for Interim Remedial Action...". We suggest you eliminate the term "final" indescribing the interim action, as it may be confusing to some readers.

Response: ATSDR will edit the text accordingly.

Comment 19: Page 23, Area 18 OU - The Army has proposed, based on data collectedsubsequent to the Area 18 ROD, that the Area 18 ROD be amended or revised, and that themulti-phase vapor extraction system may not be effective in addressing site contaminants. EPA, the Missouri Department of Natural Resources, and the Army are currently in theprocess of evaluating the Army proposal regarding the Area 18 Remedial Action. Suggestthat you may want to reflect some uncertainty in the status of Area 18 to reflect that VOCcontamination may be more widespread than was anticipated at the time of the ROD andthat the Army and regulators are considering the most appropriate manner in which toproceed.

Response: This information for the Area 18 OU will be reflected in the final release of thePHA.

Comment 20: Page 23, Installation-Wide OU - Suggest that you indicate that additionaldata collection and site evaluation is warranted to better define the nature and extent ofcontamination, and thus potential remedies, for a number of the 31 areas referenced.

Response: This suggestion will be incorporated into the final PHA.

Comment 21: Page 34, Public Health Action Plan, Actions Ongoing or Planned - In #4, weare uncertain of the nature of any formal (enforceable) land-use restrictions which havebeen implemented at the LCAAP as part of any CERCLA response actions. Please clarifythe nature of these restrictions.

In #5, we suggest you note that monitoring of off-plant groundwater contamination, downgradient of the Area 18 extraction system is planned/necessary.

Response: According to the ROD for Remedial Action at the Area 18 OU released inFebruary 1998, part of the selected remedy for Area 18 OU is to prohibit agricultural (e.g.,cattle grazing) and other non-industrial uses. In addition, as part of the remedial measuresdefined in the Final ROD for interim remedial action at the Northeast Corner OU, LCAAP isto restrict on-site worker's access to contaminated soil.

Regarding the suggestion for planned action (#5). In 1992 eight groundwater monitoring wellswere installed just off site to the north of the Area 18 and the Northeast Corner OU. Accordingto data presented in the Annual Report for LCAAP Comprehensive Groundwater MonitoringProgram, these monitoring wells have not contained levels of VOCs that exceed EPA'smaximum contaminant levels. The following clarification will be incorporated into the finalPHA: ATSDR recommends continued routine monitoring of off-site groundwatercontamination, downgradient of the Area 18 extraction system. New monitoring wells shouldbe installed off site in any locations where data gaps may be occurring.

Comment 22: Page 35, Public Health Action Plan, Recommendations - In #2, we agreethat surface water sampling at LCAAP is appropriate, but suggest that regular surfacewater monitoring (rather than a one-time sampling event) should be conducted over alimited number of rounds, perhaps quarterly for 2-5 years (depending on results), to betterevaluate possible releases of contaminants to surface water.

Response: ATSDR agrees that routine monitoring of surface water for a specified time periodis appropriate and the text will be revised accordingly.

The following are ATSDRs responses to a list of questions provided by a representative ofLCAAPs Restoration Advisory Board. The questions listed below are those that pertain specificallyto ATSDRs Public Comment Release. Some of the questions were directed to LCAAP andresponded to by LCAAP and are not listed below (the numbers in parentheses correspond to theactual number on the original list provided).

Questions submitted to ATSDR January 23, 2001.

Comment (#1): What is the actual date of the compiled information in the recent public health assessment report by the ATSDR?

Response: ATSDR relied on the most currently available information at the time of therelease of the public health assessment (Public Comment Draft) to base its public healthconclusions. Environmental sampling data for LCAAP was collected as part of a preliminaryassessment/site investigation released in January 1989 and remedial investigations for theInstallation-Wide Operable Unit (OU) (February 1994), Area 18 OU (January 1995), and theNortheast Corner OU (March 1995). The on-site drinking water supply monitoring data wasobtained for 1999, which was the most recent sampling period available. The drinking watermonitoring data from the City of Independence and the Missouri Department of Health werecollected in1998, the most recent time periods available prior to the release of the PublicComment Draft. ATSDR will continue to evaluate new information as it becomes availableand will revise its public health conclusions and recommendations accordingly.

Comment (#3): Please provide me with a map of LCAAP indicating all the areas in theATSDR report that state access to this area is restricted.

Response: ATSDR has not identified a site map that indicates areas at LCAAP that haverestricted access. However, ATSDR has corresponded with LCAAP regarding accessrestrictions to the plant. According to LCAAP officials, the entire plant perimeter is fencedwith several gated entry points around the plant. These entry points are either locked or have aguard posted. There is no evidence that trespassing onto LCAAP property has been a problemin the past. In addition to the perimeter fence, there is an inner fence that runs along and justsouth of Buckner Road. This fence encompasses about two-thirds of the plant, including theentire industrial area. There is also a fence around the firing range and special permission isrequired to access this area. Although most of the designated areas of contamination on siteare not fenced, they are contained within the plant perimeter and public access is restricted.

Comment (#6): Why is the ATSDR public health assessment report titled NorthwestLagoon which is Area #12 paint shop?

Response: This area is responsible for LCAAP being placed on EPAs National Priorities List (NPL). LCAAP was first logged into ATSDR's tracking system in reference to Area 12, as the "LCAAP Northwest Lagoon". Even though the PHA covers the entire facility, to ensure consistent record-keeping the formal title of the PHA is "Lake City Army Ammunition Plant (Northwest Lagoon).

Comment (#10): Please explain uranium metallic compounds as stated in Area #3 sandpits.

Response: In the February 1994 RI report for LCAAP it was stated that some uraniummetallic compounds were reportedly disposed of by the Department of Energy's Kansas City(Bendix) operations. However, investigations at Area 3 did not identify any radiologicalsources. According to this report, slightly elevated beta activities compared with backgroundin soil were detected (range = 5 - 6.4 pCi/kg) during the source characterization. Twogroundwater monitoring well locations in Area #3 out of a total of 20 were found to havealpha activities that exceeded ATSDR's comparison values (CVs). The maximum alpha leveldetected was 41 pCi/L (CV = 15 pCi/L).

Comment (#11): Please provide complete explanation ATSDR report page #27(evaluation of air exposure pathway)- conclusion.

Response: As stated in the Nature and Extent section of the PHA, the primary sources of airemissions from LCAAP in the past were the sealing operations units, open burning/opendetonation of wet pyrotechnics and propellant powder, and the Explosives Waste Incinerator.

Sealing Operations Units -
In the past, the sealing operations units did release some VOCs and ozone depleting chemicals. These chemicals were specifically used in the case mouth waterproofing areas and primer insert operations. According to LCAAP officials, solvents used in these areas include ethyl acetate, methyl chloroform, ethyl alcohol, methyl ethyl ketone, and toluene. The sealing operations units are located in the industrial area near the center of the plant. These VOCs would not have resulted in harm to individuals who reside near LCAAP because releases were near the center of the plant, the quantities of solvents used were relatively small, and VOCs are rapidly dispersed once released into the atmosphere.

Open Burning/Open Detonation -
The burning grounds were constructed in the middle 1950's. LCAAP operated the burning ground area for the open burning/open detonation of waste explosives, mixes, and powders. Burning activities were generally conducted once a week as long as specific weather conditions were met. Based on historical information, approximately 300 pounds of materials per week were burned at LCAAP. The most common materials burned were propellant and wet explosive scrap (e.g., calcium resinate, magnesium, barium peroxide, polyvinyl chloride, and propellant powder). The permitted burn rate for these wastes could not exceed 240 pounds per day, every day for a maximum of 1,440 pounds per week. Based on historical information, LCAAP was well under the permitted rates averaging about 60 pounds per day. According to LCAAP officials, open burning/open detonation activities were stopped in1993 (correspondence with Paul Anthamatten, March 2001). LCAAP did not conduct ambient air monitoring during burning activities and based on correspondence with Plant officials, no unusual burn events or incidents took place and ATSDR is not aware of any complaints from residents living near LCAAP during the time period that open burning /open detonation occurred.

Explosives Waste Incinerator (EWI) -
According to LCAAP officials the EWI meets all current emissions standards and has not received any notice of violations during its period of operation. The EWI was brought up to incinerator standards in 1989. Prior to 1989, it was operated as a popping furnace to incinerate small quantities of materials.

Air Pathway Public Health Hazard Determination -
Since actual air monitoring data was not available, ATSDR based its public health conclusion on historical information (e.g., types of materials, quantities, and frequency with which operations or activities occurred). ATSDR's designation of "no apparent public health hazard" recognizes that some past exposures were possible from the sealing operations units and open burning/open detonation activities, however, it is unlikely that these exposures were at levels that would pose a public health hazard.

Comment (#12): The ATSDR public health assessment report is based on availableinformation, and due to the fact that all is not known about the LCAAP site, would thisreport not be considered inconclusive and not construed as no "public health hazard"?

Response: When evaluating whether exposure has occurred, ATSDR considers how people might come into contact with, or be exposed to, contaminated media, and also considers the likely length (duration) and frequency of the exposure. If exposure was or is possible, ATSDR then considers whether chemicals were or are present at levels that might be harmful to people. It is important to emphasize that a public health hazard exists only if people come in contact with, or are otherwise exposed to, harmful levels of contaminated media.

ATSDR does not always have historical monitoring data to make conclusive statementsregarding the potential for past exposures. However, if past monitoring data is not available,ATSDR identifies the best available information in which to base its conclusions (e.g.,potential receptor populations, current monitoring data, complaints filed or other communityconcerns) and decides whether it is likely that public health hazards may have existed in thepast, may currently exist, or are likely to exist in the future.

When there is no information or very limited information available about a specific exposurepathway at a site, ATSDR may decide that additional data needs to be collected and evaluatedto determine whether a public health hazard has existed in the past or currently exists.Depending on the hazard potential of the site and the feasibility of collecting additional data,the pathway may be designated an indeterminate public health hazard. Based oncorrespondence with LCAAP officials and given what is known about the types and extent ofchemicals used at the plant, ATSDR has concluded that the overall Public Health HazardCategory for LCAAP is "No Apparent Public Health Hazard." This classification recognizesthat for certain pathways at LCAAP exposure to contaminants has occurred in the past or maybe occurring at levels that are not likely to cause adverse health effects. ATSDR's assessmentprocess is ongoing and ATSDR will reevaluate its conclusions as new information becomesavailable.

Comment (# 13): The ATSDR public health assessment report states several times andconsequently in several areas that no public health hazard exists due to the supposed factthat access to the plant and or certain areas are restricted. However, one of the mainobjectives seems to be to increase the occupancy at LCAAP, therefore how can this besafely achieved?

Response: One of the recommendations made by ATSDR in the Public Health Action Plan ofthe LCAAP PHA (p35) is that any area(s) of the plant that is/are leased out undergo a finalevaluation for environmental contaminants to meet the standards of safety and public health ofthe intended use. According to LCAAP officials, any designated area at LCAAP that isconsidered for a new use must be suitable for the type of activities that will be conducted. Anynew facilities use request at LCAAP must follow a formal evaluation and approval process.Any proposed reuse of land at LCAAP must be reviewed by LCAAP and Operations SupportCommand. Any proposed plan must meet the existing legal agreements and conditions putforth by regulatory agencies regarding land use restrictions and institutional controls.

Comment (#14): It is stated several times in the ATSDR report pertaining to severaldifferent areas that there are no drinking water supply wells located in this area. However, what is the likelihood that these identified contaminants could leach into thewater supply and or migrate from the site by other means, such as becoming airborne orsurface water runoff and consequently in the water supply?

Response: ATSDR evaluates all potential exposure pathways and considers worst caseexposure scenarios when evaluating whether a public health hazard exists. Environmentalstudies have shown that, in certain locations, the groundwater underneath LCAAP iscontaminated. However, off-site monitoring wells and private well sampling data have notidentified any contamination that would pose a public health hazard. A few of the off-siteprivate wells have contained very low levels of metals and VOCs and ATSDR recommendsthat these wells be routinely monitored in the future to ensure that the water remains safe fordrinking. Surface water has been sampled at LCAAP and there is no evidence thatcontamination is migrating off site at levels that would be of concern. ATSDRs evaluation of groundwater, surface water, sediment, and air exposure pathways has not identified anycontamination migrating off site that would pose a public health hazard.

Comment (# 15): The ATSDR report states that for area #25, there were no testsconducted in this area due to the stated fact that this area contains predominantlyasbestos related materials and access is restricted. Why were no tests conducted of thisarea and why is air sample monitoring not necessary?

Response: According to LCAAP officials, this landfill is covered with soil and vegetation.There is no completed air pathway since construction debris and asbestos related materials arenot accessible.

Comment (#16): The ATSDR report - area #21 specifically, building 3A and 12A, wereused for machining and assembly of depleted uranium (DU) and also states "no publichealth hazard exists." Was this area tested for DU contamination?

Response: Both of these buildings have been tested for DU. Initial inspections by the NuclearRegulatory Commission (NRC) indicated that building 3A required some additional cleanupof radiological contamination. Specifically, the floors of the southeast wing of building 3Awere found to be contaminated with DU. LCAAP has conducted additional decontaminationand is waiting final inspection by NRC. Any surface areas or soil samples which do not meetthe established cleanup standards will undergo further remediation as required. Cleanupactivities are expected to be completed by the end of September, 2001. According to theEnvironmental Baseline Survey (USCHPPM), Building 12A does not require any additionalclean up measures to be taken.

Comment (#17): The ATSDR report, specifically area #27A and #27B, contain DU and itwas further stated that removal of the DU was to be completed by the end of 2000. Wasthis completed?

Response: According to LCAAP officials, the cleanup of Area 27A is scheduled to becompleted by the end of September 2001. For Area 27B, the NRC has setup an agreementwith the EPA to transfer regulatory oversight to the EPA CERCLA program. The firing rangecontinues to be used by LCAAP and the area is restricted by an interior fence and onlyauthorized personnel are allowed inside the area.

Comment (# 18): ATSDR report area #28 refers to a pipeline leak that occurred in the1950's and that there were no indications of contamination, and yet the report also statesthat there are no sampling data available and that no public health hazard exists due tothe age of the spill. Why were no samples taken and would this leach into a water source?

Response: During the preliminary site investigations at LCAAP, investigators attempted toidentify the pipeline spill. According to correspondence with LCAAP, investigators wereunable to find the spill or any residual contamination. Sampling was not deemed necessarybecause it was unlikely that any residual contamination would be identified in soil orgroundwater samples.

Comment (# 19): Was the ATSDR public health assessment report conclusion, page #67,regarding off-site private drinking wells released in the year 2000 based only on testingthat occurred between 1987 to 1993 seven years prior to the release of this report?

Response: In March 1998, the Missouri Department of Health conducted additional off-sitesampling of 6 residential wells to the north of the plant (northwest quadrant). The drinkingwater in these wells met state and federal drinking water standards. Although LCAAP stoppedthe monitoring of private wells in 1993, off-site monitoring wells just north of LCAAP havenot indicated that contaminants are migrating off site. ATSDR does recommend that routineprivate well monitoring be reinstated to ensure that drinking water continues to met safedrinking water standards. Based on this information, the hazard designation for off-sitegroundwater contamination was "no apparent public health hazard." ATSDR will continue toevaluate new information and modify conclusions accordingly.

Comment (# 20): ATSDR report page #70 (summary of potential pathways at LCAAP) -air - states that ambient air sampling was not conducted in the past and other than theexplosives waste incinerator; site specific ambient air sampling of contaminated sites areto date still not taking place. Why? Please explain.

Response: According to LCAAP officials, open burning/open detonation no longer takesplace at LCAAP. New technologies have substantially reduced or eliminated the use ofsolvents and ozone depleting chemicals in the sealing operations units. Besides the ExplosivesWaste Incinerator, which is closely monitored by LCAAP, there are no other significant airemissions occurring at LCAAP.

Comment (# 21): ATSDR report area #22 states that exposure to radioactive sourceswould be of very short duration. Please explain.

Response: Area # 22 is accessed infrequently by plant personnel and the amount of exposurefrom radionuclides in soil would be very minimal. Access to LCAAP is restricted and onlyvisitors or the occasional trespasser may be present on site property. It is unlikely that visitorsor trespassers will come in contact with Area # 22 and any exposures from infrequent contact with soil would note pose a health hazard.

Additional comments sent to ATSDR July 17, 2001

Comment 1: Based on ATSDR parameters pertaining to exposure to contaminants and ofsufficient magnitude and duration for a health hazard to exist, what are or could becomehealth hazards on or off LCAAP if one or more current safeguards at LCAAP were to failand shouldn't this be included in the public health assessment?

Response: At present the environmental safeguards consist of access restriction, whichincludes a gate and security around the perimeter of LCAAP and an inner fence around theindustrial area. In addition to restricting access to unauthorized individuals, other safeguardmeasures that have been implemented include soil removal actions at source areas ofcontamination and groundwater remediation such as pump-and-treatment systems and airstrippers for the removal of VOCs. Failure of access restriction would only likely be in theform of a breach in fencing, which would be temporary. Levels of contamination in mostsource areas at LCAAP are not high enough to present a public health hazard for reasonable,short-term exposure for any scenarios which might occur. Failure of the groundwatercontainment system or of air strippers would be detected by monitoring systems, with repairsbeing initiated in a reasonably short time. Groundwater contamination levels are not highenough to present a public health hazard for short-term exposures.

Comment 2: What are the potential health hazards to the residents, employees, andcommunity regarding any contaminants leaching into the groundwater supply due to theknown fact that all contaminants exist, and to the unknown fact that all contaminants arebeing 100 percent contained on and off LCAAP property and in addition that themagnitude of contamination of all known areas is not completely certain and/or that allcontaminanted areas conclusively have been discovered?

Response: This public health assessment describes in detail the potential exposures of thecommunity to environmental contaminants from LCAAP. Extensive environmental studieshave been conducted under the oversight of state and federal regulators. It is very unlikely thatunidentified areas of contamination exist at LCAAP since preliminary assessments and siteinvestigations have sampled suspected areas of contamination throughout LCAAP.Groundwater underneath LCAAP has been extensively monitored and the drinking water onsite is closely monitored for the presence of contamination. Off- site monitoring wells to thenorth of the plant have thus far not detected contaminants that would pose a public healthhazard to residents who obtain their drinking water from shallow or intermediate wells.ATSDR recommends that LCAAP continue quarterly off site monitoring of groundwater toensure that it continues to meet safe drinking water standards.

Comment 3: Has and will ATSDR's public health assessment report take intoconsideration the various types of hazardous waste permits now in effect at LCAAP?

Response: The purpose of the ATSDR public health assessment is to evaluate thepotential public health effects of hazardous chemicals in the event that they are released intothe environment. Oversight of the waste permitting process is the responsibility and mission of stateand federal regulators. ATSDR is confident that the oversight by these regulators of the waste permits is sufficient to assure safe handling of these materials.

Comment 4: What are the potential health hazards to the community regarding anycontaminated groundwater run-off flowing into Fire Prairie Creek and consequently offLCAAP property?

Response: The potential exposures to contaminants is described in preceding sections of thisPHA. Surface water sampling conducted off site has not identified any contaminants thatwould pose a public health hazard. As a precautionary measure, ATSDR has recommendedthat surface water and sediment sampling at Fire Prairie Creek be routinely sampled to ensurethat surface water is not contaminated.

Comment 5: Due to the uncertainty of types, areas, and magnitude of contamination, is itresponsible to make a conclusive public health assessment statement that no public healthhazard exists?

Response: As described above, there have been extensive studies conducted to define theextent of contamination in the environment at LCAAP. Based on an evaluation of thesestudies, ATSDR has concluded that the contamination in soil, water, and air at LCAAP hasnot resulted in a past, current, or future public health hazard.

Comment 6: What are the potential health hazards to the residents, employees, and community in regards to various types of hazardous waste stored and/or treated atLCAAP?

Response: As discussed in #3 above, waste treatment and storage are regulated andmonitored by state and federal agencies. Current hazardous waste management practices atLCAAP are closely monitored and harmful environmental releases are not expected to occurin the future. Although past releases of contaminants into the environment has occurred andmonitoring of contaminants generally began during the 1980's, ATSDR's public healthassessment did not identify practices or conditions at LCAAP that would have likely resultedin a public health hazard. If any future releases are of sufficient magnitude that additionalpublic health evaluation is believed to be necessary ATSDR can conduct additionalevaluations.

Comment 7: Due to the various types of contamination/hazardous waste at LCAAP, isn't itprudent to take random air samples at set intervals at various sites on and off LCAAPproperty?

Response: The nature and extent of releases to the air are discussed in this public healthassessment. These consist of low level past releases of solvents from the sealing operationsunit at LCAAP during normal operations; smoke from open burning of relatively smallamounts of ordnance; and regulated and monitored normal operational emissions from the on-site incinerator. Based on discussions with plant personnel and reviews of site documents,ATSDR has concluded that these emissions were not likely harmful in the past. Additionalmeasures to reduce VOC air emissions have been taken at LCAAP in an effort to phase outozone depleting chemicals used in the manufacturing process. These actions have furtherreduced the likelihood of any potential exposures and, therefore, current and future airemissions are not expected to present a public health hazard.

Comment 8: What are or could be potential health hazards in regards to contaminantsand/or stored hazardous waste pertaining to non-facility municipal firefighters or utilityworkers om LCAAP property?

Response: Standard operating procedures involving coordination between LCAAP and fire-fighting personnel are required by law and are monitored by OSHA. Such procedures arestandard for any fire-fighting activity. OSHA also controls the activities of utility workers accessing any industrial area, including any which might contain hazardous waste.

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