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

PUBLIC HEALTH ASSESSMENT

RSR CORPORATION
DALLAS, DALLAS COUNTY, TEXAS

APPENDICES

Appendix A - Figures


Figure 1. RSR Site Location



Figure 2. Detailed Site Map



Figure 3. Blood Lead Study



Figure 4. Isopleth Map

Appendix B - Public Comments and Responses

Comments Received during the Public Comment Period
and Texas Department of Health Response

(Note to the reader: Page and paragraph numbers are quoted from the "Public Comment"document and may differ from the page and paragraph numbers of this document.)

Commentor 1

Comments mentioned in the December 1994 public meeting:

  1. The Health Assessment is based on a two-hour drive through the community with noparticipation by local residents or their health care providers.

ATSDR and TDH staff spent two and a half hours driving and walking through the communityduring a "site visit" guided by the EPA Project Manager. This site visit was conductedspecifically to examine the physical layout and characteristics of the area and to learn more aboutEPA's remedial efforts. (Clarification of the purpose of the site visit has been added to the "SiteVisit" section of the Public Health Assessment (PHA) on page 3).

Input from local residents is very important to the health assessment process. To identifycommunity concerns at the site, TDH staff attended EPA-sponsored Open Houses and publicmeetings, talked with individual residents, and maintained contact with the EPA CommunityRelations Coordinator and the Community Outreach Officer (a contractor hired by EPA to serveas a community liaison) for the RSR Site. We also reviewed the October 1993 Resolution bymembers of the TNRCC's West Dallas Citizen's Advisory Committee and reviewed newspapercoverage of the site. A section of the PHA focuses specifically on community concerns.

We reviewed data collected by a number of local health care providers including blood lead datacollected through the Early Periodic Screening, Diagnosis, and Testing (EPSDT) program and atCity of Dallas Walk-in Clinics. A training effort for physicians was undertaken in September of1992. Approximately 20 health care providers participated in the effort and were providededucational information relating to the chemicals of concern at the site. Six of the participantspracticed in the West Dallas area.

  1. A conclusion about no risk from dust is based on only 26 samples, one of which is found to have 3,800 ppm of lead in it.

In-home environmental sampling, including dust sampling, is offered to all individuals withelevated blood lead levels identified at City of Dallas Walk-in Clinics (children with15 µg/dLand adults with levels25 µg/dL). We reviewed data collected between 1991 and 1993 when 21such followups were conducted. Dust samples were collected in the homes of these 21individuals from either the floor or the window sill, or both. It is correct that one of the homeswas found to have a lead concentration of 3,800 ppm in dust from a window sill; however, onlyone other home had a lead concentration in dust (321 ppm) that was above the City's screeninglevel. These data therefore indicate that indoor dust apparently was not a primary source ofexposure among these 21 individuals with elevated blood lead levels.

The most recent in-home sampling conducted in West Dallas was collected as part of the 1993Biological Indicators of Exposure Study. This study included 386 randomly-selected childrenand provided much more comprehensive data than the Walk-in Clinic data. As part of this study,576 dust samples were collected from children's bedrooms and the entryways of homes in WestDallas. In addition, 323 dust samples were collected from children's bedrooms and theentryways of homes in a comparison community.

The average concentration of lead in dust samples collected in children's bedrooms ranged from80 ppm (in the area of West Dallas where chips and slag had been identified) to 146 ppm (in thearea nearest the site). The average concentration of lead in dust collected from the entryways ofhomes ranged from 81 ppm (in the chips and slag area) to 205 ppm (in the comparisoncommunity).

ATSDR analyzed the relationship between lead concentrations in dust from each area of thehouse to determined whether the lead levels were related to the concentrations of lead inchildren's blood. This analysis was conducted separately for each study area. Based onATSDR's analysis, there was a (statistically significant) correlation between the concentration oflead in dust found in children's bedrooms and children's blood lead levels in both the area closestto the smelter and the "eastern low deposition area," but not in any of the other areas of the site. When the same analysis was conducted for lead in entryway dust and blood lead levels, a(statistically significant) correlation between lead in dust and blood lead levels was found amongchildren living in the "eastern low deposition area," but not among children living in any otherareas of the site.

For each home, ATSDR did an additional analysis of the average level of lead found in all typesof indoor dust samples to determine whether the level correlated with the blood lead levels ofchildren living in the home. The analysis was based on the average level of dust found in thechild's bedroom, the living area, and the entryway of the house. Results indicated that there wasa (statistically significant) correlation between average lead concentrations in indoor dust and theblood lead levels of children living in the homes only in the "eastern low deposition area." Therewas not a correlation between the average level of lead found in dust and the level of leaddetected in children's blood among children who lived in any other part the West Dallas studyarea.

In another way of analyzing the effect of environmental exposures on blood lead levels ofchildren, ATSDR used a statistical model (linear regression modelling) to simultaneouslyaccount for the effects of numerous variables (including environmental measurements ofhousehold dust, soil, interior and exterior paint, age of child, play habits, hygiene practices, andother variables) on blood lead levels. This type of analysis can provide the best indication ofwhether a single factor has an independent effect on an outcome; in other words, it gives the bestindication of whether dust represents a significant exposure route. Six models were created --one for each study area and one for all the areas combined. The models did not find a(statistically significant) relationship between the levels of interior dust found in homes and theblood lead levels observed in children in any area. According to the findings of the study,interior dust, therefore, does not represent a significant exposure pathway.

We were unable to ascertain the concentrations of lead in interior dust when the smelter wasoperating to determine whether indoor dust constituted a significant source of exposure in thepast. The 1982 Lead Smelters Study reports that indoor dust samples were collected, but thatthey were not analyzed in the report because lead levels in dust were "inexplicably low." Wewere unable to determine whether there was a problem with the collection or analysis of thesesamples or whether indoor dust samples were indeed very low at the time samples were collectedin the past. One possible explanation is that at the time the samples were collected in 1982,residents had already taken measures to clean or remove contaminated dust from the areas oftheir homes that were sampled.

  1. The Health Assessment makes no attempt to explain why the Boy's Club property isbeing recontaminated after supposedly being cleaned up.

TDH and ATSDR are aware of several theories regarding the re-accumulation of lead at theBoys/Girls Club property in the past. None of the theories of past contamination can be provedor disproved, but the most likely explanation is that the contamination found on the propertyafter it had been cleaned up came from contaminated roofing material left on the ground after thebuilding was re-roofed.

According to EPA, high levels of lead were found on Dallas Housing Authority (DHA) buildingsin the vicinity of the smelter that had flat roofs. According to EPA, the lead content of roofing material on 167 buildings in the area was tested. The concentration was high in only 20buildings, all of which were located close to the smelter and had flat roofs. EPA theorizes thatsince the tar-like material used on flat roofs expanded and became sticky during hot weather, ittrapped lead particles that were emitted from the smelter over a period of years, prior to 1984when stack emissions were ceased.

Air monitoring has been conducted from the roof of the Boys/Girls Club building since early in1984 and there is no evidence that air emission of lead have contributed to the contamination ofsoil at the Boy's Club since the smelter stopped operating. The only time that leadconcentrations in air have exceeded national regulatory standards occurred early in 1984 beforethe smelter stopped operating.

The DHA recently conducted sampling on the Boys/Girls Club property to determine the currentlevels of lead in soil. Samples collected in the grassy areas of the property did not contain anyconcentrations of lead that exceeded EPA's cleanup level. DHA conducted additional samplingin the right-of-way between the road and the sidewalk near Westmoreland Road and SingletonAvenue and found elevated levels of lead that were apparently associated with battery chips andslag. This material may have been used as part of the roadbase since it was found only in theright-of-way and was detected down to a depth of approximately 26 inches. Although thepotential for exposure to this material is minimal under ordinary circumstances, DHA removedall of the contaminated material that was identified.

  1. The Health Assessment "admits that using the EPA's cleanup guidelines, a portion of the West Dallas children will still be subject to lead levels in their blood above the danger mark of 10 deciliters."

The pathways section of the health assessment states that human exposure to contaminants in soil is occurring and may occur in the future and that the exposed population includes residents living on properties with soil lead levels below the 500 mg/kg action level for lead; this section does not evaluate the public health significance of exposure to lead in soil at these levels. The health assessment states that exposures to soil containing 500 mg/kg is not expected to produce adverse health effects.

The regression model predicting that a soil lead concentration of 500 mg/kg would result inblood lead level of 10.7 µg/dL assumes exposure to an average soil lead concentration of 500 mg/kg on a daily basis. Although soil was not removed from yards in West Dallas where randomly-selected samples were below 500 mg/kg, the average soil lead concentration in those yards is in all likelihood much lower than 500 mg/kg. Thus, the regression model would predict blood lead levels below 10 µg/dL. TDH and ATSDR will review available post-remedial sampling to determine if the concentration of lead remaining in the soil constitutes a threat to public health.

For the remediated yards, a clean-up standard of 500 mg/kg assures that the averageconcentration of lead remaining in the soil will be significantly below 500 mg/kg. Since cleanfill has been used to replace the contaminated soil, the average levels to which residents will be exposed are likely well below 200 mg/kg. EPA's studies show that the average soil lead level of remaining soil in West Dallas is less than 120 ppm. In addition, EPA's sampling shows thatalmost 90 percent of the children found to have elevated blood lead levels live in homes with soillead levels less than 250 ppm.

  1. There is no modeling to help understand past exposures.

Our estimations of past exposures are based primarily on actual blood lead levels measured inWest Dallas children in the past (particularly the 1982 Lead Study which provided the earliestcomprehensive blood lead testing data). We believe that since these data reflect the levels ofexposure that actually occurred among children in the neighborhoods near the smelter, theyprovide more reliable estimates of exposure than we could get from environmental modelling.

The blood lead testing data collected prior to 1982 indicate that exposure levels were higher prior to 1982. While these data are limited and do not provide extensive information on the extent of exposure, the findings are consistent with historical records which indicate that few emissions controls had been implemented at the smelter prior to 1982.

Other comments mentioned in a critique of the Preliminary Public Health Assessment:

  • Incomplete or Inaccurate Data


    1. TDH did not argue against cleaning up lead-contaminated indoor dust.

    2. The Preliminary Public Health Assessment addressed areas of West Dallas presentingthe most immediate potential routes for exposure and the areas for which sampling datawere available. While most of the unremediated areas (DHA property, slag piles/disposalareas, and the smelter site) are not easily accessible to the general public, TDH was unableto quantitatively evaluate potential health effects associated with exposures in these areasbecause sampling data were not available. The Preliminary Health Risk Assessmentrecommended characterizing the fate of contaminants leaving unremediated areas of thesite via surface water; the Public Health Action Plan recommended evaluation of otheroperable units of the site as additional data become available.

    3. Based on available information, TDH reported that the practice of using contaminatedfill material in yards ended in the 1960s. TDH will note that improper disposal of leadwaste continued into the 1970s. This discrepancy will not alter any conclusions regardingcurrent potential exposure.

    4. The report mentions that people live just south of the slag pile area on WestmorelandRoad. Although environmental sampling data from this area were not available for review,the report notes that the slag pile is not easily accessible to the public. The public healthsignificance of this operable unit will be determined in future reports as environmentalsampling data become available.

  • Contradictions in Text.


    1. Lead is classified as a B2 carcinogen (probable human carcinogen) based on studieswhich found that lead produces tumors in laboratory animals. Lead has not been shown tobe carcinogenic in humans.

    2. The referenced kidney problems that occurred among smelter workers years afterexposure were associated with chronically elevated blood lead levels in the range of 50 to60 µg/dL or higher. These levels are higher than those documented among West Dallasresidents. Studies of individuals who have experienced lead levels below approximately20 to 30 µg/dL generally do not indicate any additional risk for developing illnesses years after exposure.

    3. Since post-remedial sampling data and other information were not available for review,the site was classified as an "indeterminate public health hazard" in the Preliminary PublicHealth Assessment. The evidence available for review indicates that people were exposedto site contaminants in the past at levels that could be associated with adverse healtheffects, but the available evidence does not indicate that people are currently being exposedto levels of contaminants expected to cause adverse health effects. Therefore, currently theresidential area of the site constitutes "no apparent public health hazard." Additionalinformation and sampling data from other areas of the site will be reviewed as they becomeavailable.

    Ignores on-going sources of industrial lead emissions.

    1. Murmur does continue to report 500 lbs. of lead per year in air emissions to EPA. Theseemissions are an estimate by Murmur of the emissions associated with its ongoingreclamation and recycling activities. Murmur reported these estimated releases to EPAunder the category of environmental losses between 11 and 500 pounds per year althoughactual amounts may be much less than 500 pounds. According to EPA, in 1993 thecompany estimated that less than 100 pound of lead per year were emitted to theenvironment (air, water, soil, etc.). Air pollution monitors across the street from Murmurhave not detected any lead pollution from the facility since 1984 when the smelter closed(please see answer to question 3 above).

    2. We searched the TRI database for all emissions data in the West Dallas area for the fivemost recent years for which data is available (1987-91). There was no information listedfor Refinery Castings, Inc. We have called TRI database managers to determine why thisfacility was not included in the report.

    3. According to available environmental and blood lead testing data, lead emissions inWest Dallas currently are not causing on-going health problems. It is important to notethat we have no evidence that children in West Dallas who continue to have elevated bloodlead levels are being exposed to elevated levels of lead in soil (see answer to comment 2above).

Commentor 2

Your letter requests that the EPA and ATSDR buy out and relocate residents living in the mostpolluted area of West Dallas. Although ATSDR and TDH are not authorized to buy properties,they can make recommendations for reducing or eliminating human exposure. The purpose ofthe ATSDR's Public Health Assessments is to evaluate the human health impact of hazardouswaste.

Based on the environmental data and blood lead testing data that we have reviewed for the RSRPublic Health Assessment, we believe that soil removal in the residential areas has been effectiveat reducing human exposure to lead contamination. The greatest source of lead exposure waseliminated when the smelter stacks stopped operating in 1984 and subsequent soil cleanup effortseliminated the primary source of lead left behind. Lead from the smelter is no longer a majorsource of exposure in the residential areas of West Dallas.

Blood lead testing provides the best information about actual exposures that people are currentlyexperiencing. The most recent comprehensive testing was conducted by the City of Dallas in1993. It showed that approximately 8.5 percent of children in West Dallas have elevated bloodlead levels. This number is similar to the percentage of children in Texas as a whole who hadelevated blood lead levels in 1993 (9.4 percent).

You mentioned in your letter that you are particularly concerned about the area located near theDallas Housing Authority (DHA) property that "was granted relocation and reconstruction." Relocation of residents and reconstruction of DHA buildings was not required because ofcontamination. The DHA buildings are being demolished by the Department of Housing andUrban Development as part of their plans to renovate public housing.

The average blood lead level of children living in the community adjacent to DHA andimmediately downwind of the RSR smelter was 7.0 µg/dL in 1993, compared with an average level of 20.1 µg/dL detected in 1982. In the early 1980s, ten percent of children had blood leadlevels higher than 30 µg/dL. In contrast, today not a single child has a blood lead level this high. Only four of the 305 children from West Dallas who were tested in the recent study had bloodlead levels over 15 µg/dL and none had levels higher than 18 µg/dL.

Based on the information reviewed, we concluded that the soil cleanup effort has beensuccessful. The children who continue to have elevated blood lead levels are probably beingexposed to a combination of the many sources of lead common in urban environments. Some ofthese sources include lead from paint, dietary sources, improperly glazed ceramics and eatingutensils, and "take home" lead associated with parents' occupations and hobbies. According toEPA, the current average residential soil lead levels in West Dallas are less than 120 ppm. Ninety percent (90%) of the children with elevated lead levels already live in homes where soillead levels are below 250 ppm. Further lowering of the soil lead levels therefore will not provide any additional benefit in lowering blood lead levels in children.

We believe that blood lead screening should be continued for West Dallas residents and thateducational follow-up and counseling about the sources of lead exposure should be provided toindividuals identified with elevated blood lead levels. These services are currently beingprovided by the City of Dallas.

The Texas Department of Health is also available to provide educational material and to answerany additional questions about health and lead contamination in West Dallas. We would behappy to attend a meeting of the Friendship Homeowners Association for Environmental Justiceor to provide you with additional information.

Commentor 3

Your letter mentions that the Public Health Assessment report shows that ongoing lead emissionsstill exist in West Dallas and suggests that high blood lead levels among West Dallas childrenand high soil lead concentrations at the Boy's Club are evidence of this ongoing contamination. Below, we are providing additional information regarding these concerns.

Comment #1. Ongoing lead emissions still exist.

The Murmur Corporation has an active reclamation and recycling operation at the site that doesnot create detectable levels of lead air pollution. Murmur reports estimates of total emissions toEPA's Toxic Release Inventory (TRI). The Public Health Assessment contains a table ofindustrial emissions compiled from TRI reports between 1987 and 1991. The table shows thatMurmur reported releasing 500 pounds of lead per year during this period. Murmur reportedthese releases to EPA under the category of environmental losses between 11 and 500 pounds peryear; thus, the actual amount that was released may be much less than 500 pounds.

According to EPA, in 1993 the company estimated that less than 100 pound of lead per year wereemitted to the environment (air, water, soil, etc.) from its processes. Air pollution monitorsacross the street from Murmur have not detected lead levels in air above the National Amient AirQuality Standard since 1984 when the smelter closed (please see answer to comments #3 below). We will thoroughly evaluate the levels of lead contamination remaining on the smelter propertywhen we address Operable Unit 4, which is currently being assessed and cleaned up by EPA.

Comment # 2. High blood lead levels among children in the West Dallas neighborhoodprovide evidence of ongoing contamination.

We have no evidence that children in West Dallas continue to have elevated blood lead levelsresulting from exposure to lead from the RSR site. Since blood lead testing provides the bestinformation about actual exposures that people are currently experiencing, we evaluated the mostrecent comprehensive testing, which was conducted by the City of Dallas in 1993. It showed thatapproximately 8.5 percent of children in West Dallas have elevated blood lead levels (10 µg/dL). This number is similar to the percentage of children in Texas as a whole who had elevated bloodlead levels in 1993 (9.4 percent). We would expect to see more widespread occurrence ofelevated blood lead levels if children were experiencing ongoing exposures to lead from thesmelter.

In addition to finding fewer children with elevated blood lead levels, the recent study found that the average blood lead level of the children living in the community closest to the former smelter has dropped considerably since the early 1980s when emissions from the smelter were occurring. In 1993, the average blood lead level of children living in this area was 7.0 µg/dL compared with20.0 µg/dL in 1982. Only four of the 305 children from West Dallas who were tested in therecent study had blood lead levels over 15 µg/dL and none of the children had a blood lead levelhigher than 18 µg/dL.

Although the recent study identified some children in West Dallas who continue to have elevatedblood lead levels, the study did not find a relationship between the elevated blood lead levels and elevated soil lead levels. The children who have elevated blood lead levels most likely are being exposed to a combination of the many sources of lead common in urban environments. Some ofthese sources include lead from paint, dietary sources, improperly glazed ceramics and eatingutensils, and "take home" lead associated with parents' occupations and hobbies.

The environmental data that we have reviewed suggest that the greatest source of lead in theresidential areas was eliminated when the smelter stacks stopped operating in 1984. Subsequentsoil removal efforts eliminated most of the remaining contamination that constituted an exposurehazard in the residential areas.

Comment #3. Recontamination is occurring at the Boys and Girls Club on Singleton Ave.

TDH and ATSDR are aware of several theories regarding the re-accumulation of lead at theBoys/Girls Club property in the past. None of the theories of past contamination can be provedor disproved, but the most likely explanation is that the contamination found on the propertyafter it had been cleaned up came from contaminated roofing material left on the ground after thebuilding was re-roofed.

According to EPA, high levels of lead were found on Dallas Housing Authority (DHA) buildingsin the vicinity of the smelter that had flat roofs. According to EPA, the lead content of roofingmaterial on 167 buildings in the area was tested. The concentration was high in only 20buildings, all of which were located close to the smelter and had flat roofs. EPA theorizes thatsince the tar-like material used on flat roofs expanded and became sticky during hot weather, ittrapped lead particles that were emitted from the smelter over a period of years, prior to 1984when stack emissions ceased.

Air monitoring has been conducted from the roof of the Boys/Girls Club building since early in1984 and there is no evidence that air emission of lead have contributed to the contamination ofsoil at the Boys/Girls Club since the smelter stopped operating. The only time that leadconcentrations in air have exceeded national ambient air quality standards occurred early in 1984before the smelter stopped operating.

The DHA recently conducted sampling on the Boys/Girls Club property to determine the currentlevels of lead in soil. Samples collected in the grassy areas of the property did not contain anyconcentrations of lead that exceeded EPA's 500 ppm cleanup level. DHA conducted additionalsampling in the right-of-way between the road and the sidewalk near Westmoreland Road andSingleton Avenue and found elevated levels of lead that were apparently associated with batterychips and slag. This material may have been used as part of the roadbase since it was found onlyin the right-of-way and was detected down to a depth of approximately 26 inches. Although thepotential for exposure to this material is minimal under ordinary circumstances, DHA removedall of the contaminated material that was identified.

The Public Health Assessment focuses on the public health significance of environmentalexposures in the residential areas (EPA's Operable Unit 1). The other areas of the Superfund Siteincluding the smelter facility site, the dumpsites/slag disposal areas, and the Dallas HousingAuthority property are being assessed and remediated by EPA in subsequent operable units. Wewill evaluate the public health implications of contamination in these areas as data becomeavailable.

With regard to the residential areas, we have recommended that blood lead screening becontinued for West Dallas residents and that educational follow-up and counseling about thesources of lead exposure be provided to individuals identified with elevated blood lead levels. These services are currently being provided by the City of Dallas. TDH also is working with thelocal health department to provide educational materials and information to health care providersand community members about lead exposure.

Table of Contents

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

A-Z Index

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