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PRELIMINARY PUBLIC HEALTH ASSESSMENT

PETROCHEM RECYCLING CORPORATION/EKOTEK
SALT LAKE CITY, SALT LAKE COUNTY, UTAH

APPENDICES

APPENDIX A - ENVIRONMENTAL CONTAMINANT DATA

Explanation of Environmental Contaminant Data Tables

Listing a contaminant in the data tables that follow does not mean that it will cause adverse health effects from exposures. Instead, the list indicates which contaminants will be further evaluated in the public health assessment.

The data tables include the following abbreviations:

CREG = Cancer Risk Evaluation Guide
EMEG = Environmental Media Evaluation Guide
PMCLG = Proposed Maximum Contaminant Level Goal
ppm = parts per million
mg/kg/day = milligrams per kilogram per day
µg/m3 = micrograms per cubic meter of air
RfD = Reference Dose
CMRL = Chronic Minimal Risk Level
IMRL = Intermediate Minimal Risk Level
FREQ>CV = the number of times a concentration exceeded the comparison value compared to the number of times it was analyzed.

Sources of Data

TABLE 1 - ON-SITE SOIL
CONTAMINANT CONCENTRATION RANGE COMPARISON VALUE (CV) FOR INGESTION FREQ>CV
ppm ppm Source
Arsenic* 2.3j - 18.4 0.6 EMEG 14/14
Barium 144 - 3170 140 Rfd 14/14
Beryllium* ND - [0.94] 0.16 CREG 10/14
Cadmium ND - 36.1j 0.4 EMEG 9/14
Chromium 7.2 - 453 10 EMEG 10/14
Lead 98.5 - 1870j None ** N/A
Manganese* 88.6 - 387 200 Rfd 4/14
Mercury ND - 4.0 1.6 Rfd 1/14
Vanadium* [3.1] - 22.5 14 Rfd 2/14
Bis(2-ethylhexyl) phthalate ND - [1300]j 40 Rfd 2/13
Di-n-butyl-phthalate ND - 480j 200 Rfd 1/13
Pentachlorophenol ND - [91] 5.8 CREG 2/13
PCB:Aroclor-1260 ND - 1.6j 0.09 CREG 3/13
Total Chlordane ND -[4.000]j 0.5 CREG 2/13
Dieldrin ND 0.04 CREG 0/5
Heptachlor epoxide ND 0.08 CREG 0/5
j- the associated numerical value is an estimated quantity because quality control criteria were not met. However, presence of the material is reliable.

[] - the associated numerical value is an estimated quantity because the amount detected is below the contract required detection limit (CRDL). Presence of the material is reliable.

* the concentration range is within background for soils in the Salt Lake City area (42).

** There are no MRLs, Rfds, or cancer slope factors. Whenever lead is found at a site, it is further evaluated because of lead's well-documented ability to cause health effects in children at low concentrations.

The Contract Required Detection Limit (CRDL) of 4.7-11.3 ppm antimony is above a comparison value of 0.8 ppm based on Rfd. The CRDL of selenium is sometimes above the comparison value.

TABLE 2 - ON-SITE GROUNDWATER
CONTAMINANT CONCENTRATION RANGE COMPARISON VALUE (C.V.) FOR INGESTION FREQ>C.V.

 ppb ppb Source
Arsenic ND - 30.9 10 EMEG 1/5
Lead ND - [2.0] 0.0 PMCLG 1/5
Vinyl chloride * ND - 27 0.02 CREG 1/5
Benzene * ND - 12 1.21 CREG 1/5
[] - the associated numerical value is an estimated quantity because the amount detected is below the contract required detection limit (CRDL). Presence of the material is reliable.

The Contract Required Detection Limit of 3.3 ppb thallium is above a comparison value of 0.4 ppb, based on the Life Time Health Advisory.

* Sampling location PC-MW-07

Contaminants not exceeding comparison values were not listed.

TABLE 3 - OFF-SITE SOIL/SEDIMENT
CONTAMINANT CONCENTRATION RANGE COMPARISON VALUE (CV) FOR INGESTION FREQ>CV

 ppm ppm Source
Arsenic* 4.0 - 21.5 0.6 EMEG 9/9
Barium 111 - 4480 140 Rfd 8/9
Beryllium* ND - [0.95] 0.16 CREG 8/9
Cadmium ND - 4.7 0.4 EMEG 8/9
Chromium 7.9 - 38.4 0.4 EMEG 8/9
Lead 31.7j - 552j None ** N/A
Manganese 187 - 713 200 Rfd 8/9
Mercury ND - 0.49 1.6 Rfd 0/9
Vanadium* 11.6 - 28.7 14 Rfd 7/9
Bis(2-ethylhexyl) phthalate ND - 0.84j 40 Rfd 0/8
Di-n-butyl-phthalate ND - 1.5j 200 Rfd 0/8
Pentachloro-phenol ND - [0.73]j 5.8 CREG 0/8
PCB: Aroclor-1260 ND - 1.2j 0.09 CREG 4/9
Total Chlordane ND - 3.3 0.5 CREG 1/13
Dieldrin ND - 0.14j 0.04 CREG 1/9
Heptachlor epoxide ND - 1.1 0.08 CREG 2/9
j - the associated numerical value is an estimated quantity because quality control criteria were not met. However, presence of the material is reliable.

[] - the associated numerical value is an estimated quantity because the amount detected is below the contract required detection limit (CRDL). Presence of the material is reliable.

* the concentration range is within background for soils in the Salt Lake City area (42).

** A comparison value cannot be calculated for lead because there are no MRLs, Rfds, or cancer slope factors. Whenever lead is found at a site, it is further evaluated because of lead's well-documented ability to cause health effects in children at low concentrations in the environment.

The Contract Required Detection Limit of 4.8- 5.6 ppm antimony is above a comparison value of 0.8 ppm based on Rfd. The CRDL of selenium is sometimes above the comparison value.

TABLE 4 - ON- AND OFF-SITE AIR
CONTAMINANT CONCENTRATION RANGE COMPARISON VALUE (CV) FOR INHALATION FREQ>CV

 µg/m3 µg/m3 Source
Benzene ND - 18j
off-site air		 0.1 CREG 1/5
Benzene ND - 25j
on-site air		 0.1 CREG 7/20
j- the associated numerical value is an estimated quantity because quality control criteria were not met. However, presence of the material is reliable.

TABLE 5 - OFF-SITE GROUNDWATER
CONTAMINANT CONCENTRATION RANGE COMPARISON VALUE FOR INGESTION FREQ

 ppb ppb mg/kg/day Source
none exceeding comparison values in three monitoring wells
The Contract Required Detection Limit of 3.3 ppb thallium is above a comparison value of 0.4 ppb based on LTHA.

APPENDIX B - PATHWAYS ANALYSES

TABLE 6. COMPLETED EXPOSURE PATHWAYS

PATHWAY NAME EXPOSURE PATHWAY ELEMENTS TIME
SOURCE ENVIRONMENTAL MEDIA POINT(S) OF EXPOSURE ROUTE OF EXPOSURE EXPOSED POPULATION
Surface Soil P/E* and others Surface soil On-site Soil,
Residential Yards, Playgrounds		 Ingestion Children in residences immediately east and south of P/E, particularly if pica.

Adults to a lesser extent

 Past
Present
Future
Ambient Air P/E and others Air- general air quality may be poor due to industries. On Site, Off Site Inhalation All workers and residents in the general vicinity of P/E. Primarily Past

* P/E = Petrochem/EkoTek

TABLE 7. POTENTIAL EXPOSURE PATHWAYS

PATHWAY NAME EXPOSURE PATHWAY ELEMENTS TIME
SOURCE ENVIRONMENTAL MEDIA POINT OF EXPOSURE ROUTE OF EXPOSURE EXPOSED POPULATION
Surface Water P/E* Water On site near RR or past containment overflows. Ponded water. Skin Contact Ingestion
Inhalation		 Workers,
Trespassers,
Possibly adjacent residents E of P/E.		 Past
Groundwater P/E Water Municipal or private well use Ingestion Salt Lake City Residents Future
Worker Waste Material P/E Waste Material Waste Piles Skin Contact
Ingestion
Inhalation		 Workers
Trespassers 		Past
Soil Gas P/E Soil Waste Piles, on- and off- site soils Inhalation Remedial Workers Future

* P/E = Petrochem/EkoTek

TABLE 8 - ESTIMATED POPULATION FOR COMPLETED AND POTENTIAL EXPOSURE PATHWAYS

Exposed Populations and Potentially Exposed Populations Affected by a Completed or Potential Exposure Pathway* For:
Location Approx.No. of Persons Heavy Metals ex. Pb, Cr, Ar Chlorinated Solvents PCB's Phthalates Pesticides Benzene and other volatile organics
Residents and Workers from Nearby Homes and Businesses Both on- and off-site exposure Unknown Soil
Air
GW		 Soil
GW		 Soil Soil Soil Air
GW
Off-site exposure 200 Soil
Air		 Soil-limited Soil Not exposed Soil Air
GW
Site Workers <100 Soil
Air
GW 		Soil
GW		 Soil Soil Soil Air

* potential exposure pathways are shown in italics
GW = groundwater

APPENDIX C - COMPARISON OF ESTIMATED EXPOSURE DOSE TO HEALTH GUIDELINES FOR INGESTION AND CALCULATION OF CANCER RISK

TABLE 9 - COMPARISON OF ESTIMATED EXPOSURE DOSE TO HEALTH GUIDELINES FOR INGESTION

CONTAMINANT EXPOSURE PATHWAY HEALTH GUIDELINE IN MG/KG/DAY SOURCE EXCEEDED BY ESTIMATED EXPOSURE DOSE
Arsenic soil 0.0003 Rfd1 children and pica children
Barium soil 0.07 Rfd children and pica children
Beryllium soil 0.005 Rfd no
Cadmium soil 0.0002 CMRL pica children2
Chromium soil 0.005 Rfd pica children2
Lead soil none3

Manganese soil 0.1 Rfd pica children2
Mercury soil 0.0008 IMRL pica children2
Vanadium soil 0.003 IMRL4 pica children2
Polychlorinated biphenyls (PCBs) soil 0.000005 CMRL5 children and pica children
Chlordane soil 0.0006 CMRL pica children2
Dieldrin soil 0.00005 CMRL pica children2
Heptachlor epoxide soil 0.000013 Rfd children and pica children
Bis(2-ethylhexyl) phthalate soil 0.02 Rfd children and pica children
Di-n-butyl-phthalate soil 0.1 Rfd pica children
Pentachlorophenol soil 0.03 Rfd pica children

Explanation of Table 9

1 - Rfd is reference dose.

2 - Pica children are assumed to ingest five grams of soil per day.

3 - Currently, there are no health guidelines available for lead in soil. Whenever lead is found at a site, it is further evaluated because of lead's well-documented ability to cause health effects in children at low concentrations in the environment.

4 - IMRL is intermediate minimal risk level.

5 - CMRL is chronic minimal risk level.

Calculation of Exposure Doses for Soil Ingestion

The exposure doses for soil ingestion were calculated in the following manner. The maximum concentration for a contaminant was multiplied by the soil ingestion rate for adults, 0.0001 kg/day; children, 0.0002 kg/day, or pica children, 0.005 kg/day. (The habit of ingesting large amounts of soil is called pica.) This product was divided by the average weight for an adult, 70 kg (154 pounds) or for a child, 10 kg (22 pounds). These calculations assume that there is frequent daily exposure to soil contaminated at the maximum level. A qualitative summary of these results can be found in Table 9, Appendix C.

Calculation of Risk of Carcinogenic Effects

Carcinogenic risk from soil ingestion was calculated through the following. The maximum concentration of a contaminant was multiplied by the soil ingestion rate for adults of 0.0001 kg/day, then this result is divided by the average adult body weight of 70 kg. This product is multiplied by the EPA's Cancer Slope Factor for the contaminant. The result represents the maximum risk for cancer after 70 years of exposure to the maximum concentration of the contaminant. Cancer slope factors were available for beryllium, PCB, chlordane, dieldrin, bis(2-ethylhexyl)phthalate, di-n-butyl-phthalate, pentachlorophenol, and heptachlor epoxide (20).

The actual risk of cancer is probably lower than the calculated number. The method used to calculate EPA's Cancer Slope Factor assumes that high dose animal data can be used to estimate the risk for low dose exposures in humans (17). The method also assumes that there is no safe level for exposure (18). There is little experimental evidence to confirm or refute those two assumptions. Lastly, the method computes the 95% upper bound for the risk, rather the average risk, which results in there being a very good chance that the risk is actually lower, perhaps several orders of magnitude (19).

APPENDIX D - FIGURES 1 THROUGH 3

Figure 1
Figure 1.

Figure 2
Figure 2.

Figure 3
Figure 3.

APPENDIX E - PUBLIC COMMENTS

RESPONSE TO COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD FOR PETROCHEM PUBLIC HEALTH ASSESSMENT

The Petrochem Public Health Assessment was available for public review and comment from November 10, 1992 through December 8, 1992. The Public Comment Period was announced in local newspapers; the resident and business owners in the Swedetown area were notified by letter. Copies of the public health assessment were made available for review at the Rose Park Branch Library, the Non-Fiction Reference Section of the Salt Lake City Public Library, and the Utah Department of Environmental Quality. In addition, the public health assessment was sent to seven persons or organizations who requested copies. Comments were received from one person, EPA, and UDEQ.

Comments and responses are summarized below. The comment letters can be requested from ATSDR through the Freedom of Information Act.

COMMENT: In general it appears that the population of Swedetown is too small to be significant to most of your formulas. The surface samples are only expected to give you preliminary evidence. So I am skeptical that your results claim that is no threat to human health except for Pica kids.
RESPONSE: Except for health outcome data, the evaluations in the public health assessment are not dependent on population size. However, the toxicological evaluations are very dependent on the quality and quantity of the environmental sampling data. Because of the overall inadequacy of the environmental data for this site, ATSDR could not determine whether the site represents a health hazard and made recommendations to fill the data gaps.

ATSDR appreciates your skepticism. Our conclusions are only valid for the limited data we evaluated for Swedetown residential area and were not intended to mean that the site is safe. The data are inadequate for such a determination. To better identify the possible health threat, ATSDR recommends that additional sampling of the residential area be done.

COMMENT: One wonders if this site is not a serious threat, how can so many millions of dollars be spent on it's behalf?
RESPONSE: As stated above, the environmental data are inadequate for determining whether the Petrochem site is currently a health hazard. This site was a health hazard in the past, which is why it was closed and the worst areas of contamination removed. Any remaining areas of contamination on site and any contaminants that moved off-site should be identified during the remedial investigation and then cleaned up.
COMMENT: In order to place the previous investigations/results in their proper context, ATSDR should include in the Summary section a brief description of the Superfund process, and where the Petrochem/Ekotek site stands in that process. It should also be pointed out that earlier investigations were not intended to be comprehensive and that the information found lacking in the earlier stages will be addressed during the upcoming Remedial Investigation for the site.
RESPONSE: These are very good suggestions. The Background section of the public health assessment will be revised to include information on the Superfund process. A brief mention will also be made in the Summary. The purpose of earlier environmental investigations and that a RI will be done will be mentioned in the Environmental Contamination and Other Hazards section.
COMMENT: Page 1, paragraph and Page 2, paragraph 2. The last sentences should be changed to state "the site was added to the National Priorities List in October 1992."
RESPONSE: Thanks for this new information. The public health assessment will be revised accordingly.
COMMENT: Page 3, paragraph 4. The second sentence should read "Since then security has been provided on a drive-by basis.
RESPONSE: The public health assessment has been revised to reflect this change.
COMMENT: The following is an example of contradictory statements within the public health assessment. In the Summary, page 1, paragraph 2, it is stated that the "ambient air pathway cannot be fully evaluated for health implications because of the lack of monitoring during plant operations." In the Recommendations, page 27, it is stated that "...people may have been exposed to contaminants at levels that may cause illness or disease..." However, in the response to Community Health Concerns Evaluation, page 23, question 1, an evaluation of health implication is made in spite of the lack of air monitoring data and potential exposure to contaminants which may have caused illness or disease. It may be ATSDR's belief that long-term health effects are unlikely; the Utah's Department of Environmental Quality (UDEQ) does not share in this confidence in the presence of all the uncertainties.
RESPONSE: These statements are not contradictory. In a public health assessment, ATSDR evaluates the possible health impact of the entire site, and the environmental data for each media. For Petrochem, the site was determined to be an indeterminate public health hazard because data were inadequate. Likewise, the environmental data for the air pathway were inadequate for a full evaluation.

However, the soil sampling data were adequate, though barely so, for evaluating health implications for this media. This lead to the conclusion that the maximum levels of arsenic, cadmium, and barium in residential soil might result in adverse health effects in some children. The statement in the Recommendations that people may have been exposed is based on these conclusions.

The response to question 1 in the Community Health Concerns Evaluation section is not contradictory. It is based on a specific question posed by a business owner. The question was whether employees would suffer long-term effects from the short-term acute illnesses they experienced from emissions from the plant while it was in operation. It was reported that those illnesses were experienced several times a year for 10 years and that symptoms were mild and recovery was rapid. Given this specific exposure scenario, long-term effects are unlikely. However, given another scenario, such as daily low level exposures, it is not possible to exclude the possibility of long-term effects.

The commenter states that "It may be ATSDR's belief that long-term health effects are unlikely; UDEQ does not share in this confidence in the presence of all the uncertainties." ATSDR response to question 1 relates only to the question and exposure scenario posed by the business owner. As stated previously, the possibility of long-term effects from other exposure situations can not be eliminated.

COMMENT: The following is another example of contradictory statements within the public health assessment. Page 1, paragraph 5 states the following: "...the extent and sources of off-site contamination of the residential soil and ground water are unknown.", and, "...there are many estimates in the data obtained which are inadequate for determining public health implications." Yet earlier in paragraph 3 of the Summary section, the statement is made that "...maximum concentrations of other soil contaminants (other than arsenic and barium) were not a health concern. Such a statement cannot be made if the data reviewed is inadequate for determining public health implications.
RESPONSE: As stated earlier, ATSDR evaluates the possible health impact of the entire site, and the environmental data for each media. For Petrochem, the site was determined to be an indeterminate public health hazard because of the inadequacy of the data. However, the soil sampling data were adequate, though barely so, for evaluating health implications for this media.

ATSDR does not consider this approach contradictory. Environmental data often are adequate for one media but not for an entire site. ATSDR has a responsibility to make health evaluations for any media where the data is adequate, even though, as is the case with Petrochem, the source of contamination is uncertain.

COMMENT: The following is a third example of contradictory statements within the public health assessment. The Summary, page 1 and in the Conclusions, page 25, states that the site represents "an indeterminate public health hazard because the environmental data reviewed are inadequate for fully assessing the possible impact of this site on public health" and "extent of off-site groundwater and soil contamination has not been determined." Even though insufficient data exists to assess the impact on public health, the authors encourage the residents to eat the vegetables out of their gardens, acknowledging that "small amounts of contaminants may be on or in the vegetables", and permitting the children to play in the dirt. Because of the uncertainties surrounding this site until further testing is done, UDEQ does not agree with ATSDR's response to questions 4 and 5 on page 24.
RESPONSE: As with the other two examples given by the commenter of contradictions, the problem is whether the entire site is being evaluated or a specific media. The soil data are adequate to make the responses to questions 4 (permitting children to play in the dirt) and 5 (stating that vegetables are safe to eat).
COMMENT: It was stated in UDEQ's previous comments on the Initial Release for the Health Assessment that despite the title, Possible Health Consequences of the Exposure Doses (page 17), no health consequences are noted. What are the symptoms of exposure to the contaminants of concern? The description of the possible health effects from exposure to barium was better in the Initial Release HA than in the current HA.
RESPONSE: Possible health consequences (i.e., that adverse health effects may occur) are noted for arsenic, barium, and cadmium. The listing of possible symptoms is an uncertain exercise when animal data are being used to predict whether human health effects will occur. Since most of the discussions of possible health consequences were based on animal data, it was decided to be consistent for all the discussions and not list possible symptoms.
COMMENT: The typical/natural levels for inorganics referred to in the report are based on a table summarizing "background" soil samples from approximately 23 pre-remedial Site Investigations in the Salt Lake City area (reference #42). This summary has its limitations and was not intended to represent actual background conditions for the Salt Lake area. Indeed, the variability in the concentrations for most of the compounds indicate that a much larger sample size would be required in order to determine representative background concentrations. Conclusions such as the one made for arsenic concentrations (page 17, paragraph 4, first sentence) based on reference #42 should be changed accordingly.
RESPONSE: The data from the 23 pre-remedial Site Investigations was given to ATSDR by UDEQ as "background data." UDEQ stated in their comments on the initial release of the Petrochem Public Health Assessment, "The levels of arsenic found in residential soils are at background levels for the Salt Lake Valley." The data appear to be adequate for the purpose they are used for in the document. "Naturally occurring" in the first sentence of paragraph 4 on page 17 has been deleted.
COMMENT: Page 27, paragraphs 4 and 5. What biological indicators of exposure are recommended by HARP? Petrochem has been inactive for over 4 years; what biological indicator proposed will determine ambient exposure to site-related contaminants after 4 years of inactivity? Who will conduct this testing? Who will be responsible for conducting the health statistics review and community health investigation to community concerns about cancer?
RESPONSE: The biological indicators of exposure recommended by HARP would be those appropriate for the known exposures (i.e., metals in soil). It is not known whether these exposures are site-related.

As far as what biological indicators would indicate exposure to site-related contaminants after four years of inactivity, this would be any indicator for which exposure is still occurring. The type and extent of off-site movement of site contaminants and the possibility of exposure to them, hopefully, will be answered by the Remedial Investigation.

The biological indicator testing and the other public health actions, if needed, can be done by the State of Utah, either using their or ATSDR funds, as available, or by ATSDR. The State of Utah has already begun to address the community concerns about cancer.

COMMENT: Overall the document is difficult to understand. There are numerous discrepancies and contradictions that remain that should be addressed in a general re-write of this document. The authors should recognize that their audience is the general public and provide an adequate level of explanation, making sure that the discussions in the text supports their conclusions/recommendations. Discussions, such as the one on page 17 regarding arsenic, leave the reader with more questions than answers. Sections such as this need to be re-written in clear concise language.
RESPONSE: Many of the general concerns mentioned have already been addressed in earlier responses. The three specific examples of contradictions given, are not contradictions. No examples of discrepancies were given, so a response can not be made.

Every effort has been made to write public health assessments that can be useful, informative, and understandable to the general public. The document was reviewed by technical experts, professional editors, and administrators within ATSDR. In addition, the residents, business owners, and others have been communicated with regularly throughout the development of the public health assessment. Suggestions for improving the readability of the public health assessment (in general) are welcomed. Please send recommendations to: Director, Division of Health Assessment and Consultation, ATSDR, Mail Stop E-32, 1600 Clifton Road, Atlanta, GA 30333.

COMMENT: Summary/3: The list of soil contaminants should be prefaced with a statement that this list is based upon existing sampling, and should not be presented as a complete list. EPA must repeat the comment it made on 31 August 1992 in a review letter for an earlier draft of this report. While a great deal of information is known about the now-removed primary sources of contamination at the Site, relatively little is known about the remaining contamination of the Site soils and ground water. Even less is known concerning the potential pathways for contamination to migrate from the Site, and the exposure pathways which may affect off-site receptors. These information needs are the primary purpose for conducting a Remedial Investigation and Feasibility Study (RI/FS), which is now underway.
RESPONSE: The list of contaminants in the soil exposure pathway in the Summary is not described as being complete or incomplete. The sources of the sampling data are described in the Environmental Contamination and Other Hazards section (page 7, paragraph 1) and the limitations of those data are mentioned numerous times in the public health assessment, especially paragraph 5 of the summary.
COMMENT: Summary/5: ATSDR recommends that EPA and UDEQ better characterize off-site ground water and soil contamination. This implies that off-site contamination exists, and that it is the result of Site activities. During the RI, pathways for contamination to migrate from the Site will be investigated. However, the Site is located in an industrial area, and there are many potential sources of off-site contamination other than the Petrochem Site. Off-site soil contamination is especially difficult to attribute to a particular source. Unless off-site contamination can be scientifically attributed to the Site, EPA has no authority with respect to the Site to address such contamination. Therefore, ATSDR's recommendation should be modified.
RESPONSE: ATSDR is required by the Superfund Amendments and Reauthorization Act of 1986 (SARA) to release a public health assessment on a site within one year after a site is proposed for the National Priorities List (NPL). This often means that the public health assessment has to be written before comprehensive environmental sampling such as found in an RI is conducted. The Petrochem Preliminary Public Health Assessment is identified as "Preliminary" because of the lack of those comprehensive data. For Petrochem, the site was determined to be an indeterminate public health hazard because of the inadequacy of most of the data. However, the soil sampling data were adequate, though barely so, for evaluating health implications for this media.

ATSDR has a responsibility to make health evaluations for any media where the data is adequate, even though, as is the case with Petrochem, the source of soil contamination is uncertain. The recommendation for further characterization was made to help determine the role of the site, if any, in contributing to off-site contamination. In addition, ATSDR has a responsibility to recommend further sampling that would quantify possible human exposures, even if those exposures are not site-related.

Recommendation 2 in the Recommendations section was written with those two goals in mind. Sampling at the perimeter of the site, as recommended, is a common way of identifying whether contaminants have moved off-site. As documented in the public health assessment, there is good anecdotal evidence that contaminants have been moved off-site to the west. Additional sampling in the residential area of Swedetown is needed to better quantify the contaminant levels and the health risk. The source of those contaminants is uncertain.

The commenter raises a concern about EPA's lack of authority to perform sampling not related to the site. It has been the experience of ATSDR that EPA or state environmental agencies usually have the authority and responsibility, though not always the funding, to perform environmental sampling when the source is uncertain. Recommendation 2 identifies the need for additional sampling but in no way obligates any agency to perform that sampling. SARA mandates that ATSDR identify additional sampling needs in the public health assessment.

ATSDR will be contacting EPA and the Utah Department of Environmental Quality (UDEQ) before this document goes final to identify whether they can commit to perform any of the recommended sampling. Commitments to implement or actual implementation of any of the recommendations by ATSDR, EPA, UDEQ, or other agencies will be placed in a Public Health Actions section.

COMMENT: Page 2/paragraph 2: The Site was added to the National Priorities List on October 14, 1992.
RESPONSE: The public health assessment has been revised to include this new information.
COMMENT: Page 9/paragraph 2: With respect to soil gas and off-site contamination, EPA must repeat its 31 August 1992 comment. EPA fails to see the relevance of chlorinated solvents being discovered in off-site soil gas. No link, such as a potential pathway, has been made between the Site and these off-site gases. In addition, ATSDR states that the presence of off-site soil gas indicates that off-site groundwater needs to be characterized further. This implies without a scientific basis that the Site has contaminated both off-site soil gas and off-site ground water. This entire paragraph should be deleted.
RESPONSE: This commenter stated earlier that, "...relatively little is known about the remaining contamination of the Site soils and ground water. Even less is known concerning the potential pathways for contamination to migrate from the Site, and the exposure pathways which may affect off-site receptors. These information needs are the primary purpose for conducting a Remedial Investigation and Feasibility Study (RI/FS)..." The recommendation to further characterize off-site groundwater is one of the ways to fill those information needs. The finding of chlorinated solvents in soil gas off-site demonstrates the need for further characterization since chlorinated solvents have been found on site. Sampling such as done during an RI will likely indicate whether there is a link.
COMMENT: Page 11/paragraph 2: Regarding the soil pathway with respect to off-site soil, EPA must firmly repeat its 31 August 1992 comment. As described above in Comment No. 2, relatively little is known about on-site contamination. Until the RI/FS is thoroughly underway and on-site characterization has been completed, any speculation relating off-site soil contamination to the Site will remain inconclusive. Contaminants have been found in off-site soil, some of which are also found in on-site soil. However, given the industrial nature of the area, one cannot automatically attribute this contamination to the Site, as this report implies. Therefore, ATSDR should revise its conclusion of a completed exposure pathway with relation to off-site soils. While off-site contamination does exist, within the context of this report the determination of a completed exposure pathway implies the source of contamination is the Petrochem Site. In addition, the comment may well prove unnecessary. However, if the RI/FS data indicates that this off-site sampling is indeed necessary, EPA shall ensure that a thorough sampling investigation is conducted to protect the nearby community and environment. This issue of off-site soil should be revised not only in this paragraph, but in all similar paragraphs throughout the document.
RESPONSE: The second sentence of this paragraph has been deleted to help clarify this issue. However, as described on pages 10-11 of the public health assessment, ATSDR considers an exposure pathway complete when there is good evidence of human exposure. The source of the contaminants does not have to be ascertained for an exposure pathway to be considered complete. ATSDR mentions throughout the document the possible contribution of other sources to soil contamination off-site.
COMMENT: Page 12/paragraph 5: EPA strongly objects to the conclusion of soil gas as a potential exposure pathway. ATSDR agreed in a 19 October 1992 letter to EPA with EPA's comment that until the source of off-site soil gases is identified, no link can be made between the gases and the Site. ATSDR should delete this conclusion, not only in this paragraph, but also in all similar text throughout the document.
RESPONSE: Similar to completed pathways, the source of contamination need not be known for ATSDR to consider a potential exposure pathway to exist.
COMMENT: Page 17/paragraph 1: ATSDR discusses possible health consequences resulting from exposure to off-site contaminated soil. As described above in Comments No. 2 and 5, there are several potential sources for off-site soil contaminants other than the Petrochem Site. However, this paragraph implies that exposure to this off-site soil can be attributed to Petrochem. This paragraph should be revised, and also any similar paragraphs in the text.
RESPONSE: The fourth sentence of this paragraph has been revised as follows to remove this implication.
    Thus they may not be indicative of the consequences of ingesting soil from other areas in Swedetown near the Petrochem site because the levels aremay be either lower or unknown.
COMMENT: Page 26/Recommendation 2: ATSDR states that the soil of adjacent businesses and residences and the nearby Swedetown residences should be sampled. This recommendation should be deleted. ATSDR agreed in a 19 October 1992 letter with EPA's original comment that characterization, including comprehensive sampling, of off-site residential soil, ground water and air is premature and may well prove to be unnecessary.
RESPONSE: ATSDR agreed with the original comment and deleted the sentence quoted. The original comment was "Your statements in paragraph 4 of the Summary that 'off-site residential soil, groundwater, and air need (emphasis added) further characterization including comprehensive sampling' are premature and may well prove to be unnecessary." We did not mean to indicate that further characterization was unnecessary. As described in an earlier response, ATSDR has a responsibility to make such recommendations.
COMMENT: Page 27/Recommendation 3: ATSDR recommends that ambient air be monitored near locations where surface soil gas contaminants are identified. As described above in Comment No. 6, EPA and ATSDR have previously agreed that any off-site air sampling is premature.
RESPONSE: ATSDR did not intend its response to a comment on a specific sentence in the Summary section of the Initial Release to include other parts of the document. We apologize for any misunderstanding that may have occurred.

Recommendation 3 is another of the information needs identified by the commenter that can be addressed in an RI.

FOOTNOTES

1. The National Toxicology Program in its Annual Report on Carcinogens classifies a chemical as a "known human carcinogen" based on sufficient human data. Its classification of a chemical as being "reasonablely anticipated to be a carcinogen" is based on limited human or sufficient animal data.

2. IARC defines a class 1 carcinogen as a substance which studies in humans indicate a causal relationship between the agent and human cancer. Class 2 carcinogens are those reasonably anticipated to be carcinogens. For a 2A classification, there is limited evidence of carcinogenicity from human studies which indicate that a causal interpretation is credible, but not conclusive. A classification of 2B indicates that there is sufficient evidence of carcinogenicity from studies in experimental animals.

3. In EPA's classification scheme, a chemical is considered a class A or human carcinogen based on sufficient evidence from studies of humans. A substance is considered class B1 if there is limited evidence from human studies. B2 is used when evidence for carcinogenicity is inadequate or non-existent based on human studies, but sufficient based on animal studies.

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