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Congressional Testimony
ATSDR's Progress in Meeting Congressional Mandates
Testimony by Barry L. Johnson, Ph.D.
Assistant Surgeon General
Assistant Administrator
Agency for Toxic Substances and Disease Registry
Public Health Service
U. S. Department of Health and Human Services
Before the
Subcommittee on Oversight
Committee on Ways and Means
House of Representatives
August 12, 1992
The Agency for Toxic Substances and Disease Registry (ATSDR) was created by the Superfund legislation in 1980 (more formally known as the Comprehensive Environmental Response, Compensation and Liability Act, or CERCLA). Our understanding of the Congressional intent in creating ATSDR was to establish an independent health and science advisor for the Environmental Protection Agency (EPA), the States, and of course Congress, concerning the public health hazards associated with Superfund sites and emergencies involving hazardous substances. Specifically we were charged in 1980 with determining the relationship between exposure to toxic substances and human illness, in addition to such specific activities as creating an exposure and disease registry, an inventory of health information on toxic substances, a listing of sites closed to the public because of toxic contamination, and providing medical assistance in public health emergencies involving toxic substances.
The 1986 Superfund Amendments gave ATSDR greater responsibilities in several areas. We were mandated to provide public health assessments of all National Priorities List (NPL) sites, with the added provision for follow-up health activities such as health studies, health surveillance, or registries as needed. We were also given responsibility for determining which substances posed the greatest health hazard and for writing toxicological profiles for each of those substances. As a consequence of writing these profiles we were also charged with determining where were major gaps in information about the health effects of these substances, exist and for establishing an applied research agenda to fill the most critical information needs. Finally, we were also given the task of developing educational materials for health professionals, primarily physicians, concerning the diagnosis and treatment of patients exposed to toxic substances. ATSDR does not participate in the determination of levels of hazardous substances for site remediations unless asked by EPA or a state as a matter of health advice.
Perhaps one of the best ways to illustrate our activities at Superfund sites, Mr. Chairman, is to describe events at an actual site. The Crystal Chemical site, one of the more than l,200 sites on the EPA's National Priorities List (NPL), lies in the pathway of Houston, Texas' rapidly expanding suburbs. Within a mile of the site are shopping centers, restaurants, apartments, single-family houses, commercial offices, and light industrial businesses. In the immediate area are 8,000 apartment units, 2,500 condominiums and 9 million square feet of commercial space employing some 65,000 people.
Between 1968 through 1981, the Crystal Chemical Company manufactured arsenic-based herbicides. The site was known to be contaminated. During the 1970's, flood waters carried contaminants off the site and into flood control channels and ditches. In September 1981, literally the day before EPA started its immediate removal action at the site, the company declared bankruptcy, and abandoned the site. The company left 99,000 gallons of arsenic trioxide in a storage tank and about 600,000 gallons of processed wastewater in treatment ponds. Up to one foot of storm water, contaminated with arsenic from contact with soil and processed wastewater, covered the entire 5-acre site.
ATSDR's review of on-site and off-site sampling data from EPA documented a health concern due to the elevated levels of arsenic in soil, sediment, surface water and ground water. In view of the elevated environmental levels and the potential pathways of exposure that existed for children or adults who spent time on or near the site, we determined a health study was needed to see if the contaminated site posed a public health problem.
All residents who had lived in an apartment complex adjacent to the site were considered for the study, and urine specimens were requested from children and adults from two groups. One group was based on random samples of apartment residents and one based on responses that placed them at potential risk of exposure from play or other activities in contaminated areas.
The study results showed that although widespread exposure to arsenic was not occurring, several children from the apartment complex were found to have biological levels in urine of arsenic of health concern. EPA erected a fence to prevent access to the site and ATSDR and the county health department conducted a health education effort to inform parents of the hazard of contact with arsenic. Following site remediation by EPA, the children were retested, and all were found to have arsenic levels in urine well below the level of health concern.
As you can see from this example, one of our most important activities is to conduct public health assessments at all Superfund NPL sites. These assessments are an evaluation of data and information on the release of hazardous substances into the environment to 1) assess any current or future impact on public health, 2) develop health advisories or other health recommendations, and 3) identify studies or actions needed to evaluate and mitigate or prevent adverse human health effects.
An ATSDR public health assessment gathers information about hazardous substances at a site and evaluates whether exposure to those substances might cause harm to people. To make these determinations, ATSDR looks at three primary sources of information:
The public health assessment is essential for the identification of appropriate public health follow-up. The public health assessment provides advice to EPA and States on actions to reduce or prevent possible exposure to hazardous substances. This was clearly the case at Crystal Chemical where EPA initiated rapid action to eliminate the off-site migration of arsenic where children could come into contact with contaminated soils, and thereby prevented additional exposure.
Unfortunately, our early involvement in activities at the Crystal Chemical site is not always typical of ATSDR's role at Superfund sites. In the normal course of events EPA goes through a process to identify sites for inclusion on the National Priorities List (NPL) and to select the appropriate clean-up action. This process includes site discovery, preliminary assessment, site investigation, proposal for inclusion on the NPL, remedial investigation, feasibility study, and choice of remedial clean-up (or Record of Decision, ROD).
As a general rule, ATSDR has not been able to complete its public health assessments in a manner timely enough for them to be of most benefit to EPA and states. This is because the Agency is mandated to conduct a health assessment of all sites placed on, or proposed for, the NPL (which now numbers in excess of 1,300 sites), in addition to sites that are petitioned by citizens and public officials (over 200 petitions have been received). The past health assessment workload has prevented ATSDR from getting involved with EPA earlier in the process of site discovery, identification, remedial study, and remedial action. Because ATSDR has been involved in this process so late, our public health assessments are frequently not available for EPA regional or headquarters staff for use in their consideration of clean-up alternatives.
We are actively working with EPA to increase our involvement earlier in the EPA process. ATSDR would like to be a party to the site investigation where we can work with EPA to determine appropriate on-site and off-site sampling, and raise any health concerns at the earliest possible time. Through a more flexible approach to public health assessments -- and ATSDR health consultations -- we would hope to evaluate environmental sampling data as well as citizen health concerns, and make appropriate health recommendations to EPA well before decisions on final clean-up.
In the conduct of health assessments, ATSDR currently treats all sites as being of equal health concern. Based on recent experience, one way we will be improving our public health assessments will be to prioritize sites according to potential health impact. Sites not ranking high on the health prioritization scheme can then be placed by ATSDR in a health monitoring category. High ranking sites would indicate the need for a full public health assessment, which will then be done. Such a revision of current practice will assure a more efficient use of our resources.
Another significant mandate for ATSDR is to increase our understanding of the relationship between exposure to hazardous substances and adverse human health effects through epidemiologic, surveillance and other studies of toxic substances and their effects.
To date, ATSDR has initiated 93 separate health studies. These health studies, conducted by ATSDR staff or supported by ATSDR funding, have yielded important findings -- both documenting adverse health outcomes and documenting the lack of adverse health problems.
For example, a health study sponsored by ATSDR of workers and their families at the Olin Chemical Company Superfund site in Charleston, Tennessee found mercury exposure among the families of workers. Exposure was related to workers bringing mercury home on their clothing which created excess household air concentrations. Because of this study, specialized cleaning of contaminated homes was conducted under EPA's oversight, thereby reducing mercury vapor levels (and the potential of human exposure) in these homes.
A study of lead exposure in Grand Junction, Colorado also showed evidence of human exposure. ATSDR determined that a blood lead testing project was needed for the Riverside community, based on a finding of environmental lead levels as high as 20,000 parts per million (ppm) on a Superfund site that had unrestricted access to the public. Most children living in nearby residences were tested for blood lead levels -- and six children of the 53 children tested were found to have blood lead levels in excess of 10 micrograms of lead per deciliter of blood (mg/dl) -- the current level of health concern established by the Centers for Disease Control. These children are now being followed-up by the local public health department to monitor their blood lead levels. EPA has also taken preventive action based on the health study results. The site was fenced to prevent children from getting onto the site, and off-site sampling of residential yards is being conducted.
Another example of ATSDR's health assessment occurred at the Forest Glen site in New York. This Niagara Falls community consisted of 51 mobile homes with about 150 residents, including one family who had been displaced earlier from Love Canal. Before Forest Glen became a mobile home park during the 1970s and early 1980s, the area had been used as a landfill for chemical waste containing hazardous substances. Residents reported seeing discharges of resinous materials on the surface of the ground and high concentrations of contaminants were detected in surface soils.
ATSDR and the New York State Health Department found several actual and potential health hazards at the site. Normal daily activities of residents, such as gardening or playing in the yard, led to contact with contaminated soil which resulted in adverse health effects (allergic contact dermatitis, phototoxic skin reactions) in some residents. Because of the urgency of health risks at this site, ATSDR issued a Health Advisory in July 1989, recommending that residents of this mobile home park be relocated immediately and that the site be added to the NPL. In response, EPA and the Federal Emergency Management Agency temporarily relocated Forest Glen residents and started a voluntary buyout program for their mobile homes when Forest Glen was added to the NPL.
However, in spite of ATSDR's best efforts over the less than 10 years of our existence, we recognize that the national extent of adverse human health effects associated with hazardous wastes in the environment remains unknown, though progress is being made.
During fiscal year 1991 ATSDR evaluated data from 261 public health assessments. This ongoing, agency review is conducted by a panel of physicians, epidemiologists, toxicologists, and other health specialists. From this review, the Agency recommended health actions for 38 percent of the sites. The recommendations consisted of such actions as conducting exposure studies, health effects studies, community health education, and physician education programs.
Another source of information is the study by the National Research Council (NRC) which assessed the published scientific literature on health effects of hazardous wastes. The NRC in their 1991 report Environmental Epidemiology: Public Health and Hazardous Wastes concluded "Although current public health burdens from hazardous-waste sites appear to be small, the future risk might be greater insofar as materials already in the groundwater can migrate into areas where exposure potential is greater. ... We are concerned that populations may be at risk that have not been adequately identified. ..."
Nevertheless, despite the lack of adequate data with which to characterize the effects of hazardous wastes on public health in general, the NRC Committee found that sufficient evidence does exist that hazardous wastes have produced serious health effects in some populations. Several epidemiologic studies at specific sites have documented a variety of symptoms of ill health in exposed persons, including low birth weight, cardiac anomalies, headache, fatigue, and neurobehavioral problems. Some studies have detected excesses of cancer in residents exposed to certain substances that are found at hazardous waste sites.
The NRC Committee recommended that a number of research strategies and techniques be applied to the study of health effects linked with hazardous wastes, including the use of "sentinel health events" as indicators of contamination and exposure. The report concludes with the exhortation a window of opportunity exists to initiate studies in areas of contamination and an important opportunity for prevention that could forestall major public health problems in the future. We as a nation are currently unable to answer many significant questions of the impact on public health of hazardous wastes and, until better evidence is developed, "prudent public policy demands that a margin of safety be provided regarding potential health risks from exposures to substances from hazardous-waste sites."
ATSDR concurs with these findings, and has taken steps to implement many of the recommendations included in the National Research Council's report. In order to better determine the adverse human health conditions related to populations living near Superfund sites, ATSDR has identified the following seven Priority Health Conditions for particular study.
Study of these adverse health conditions at selected Superfund sites will hopefully enable us to understand the association between exposures to hazardous substances and the likelihood of resulting illness. The first of these studies was initiated last year at 4 lead sites where the community residents are being tested for kidney, liver, immune and blood disorders, and the relationship between blood lead levels and levels of lead in soil. We hope to have the results of these studies shortly.
In 1986 Congress was concerned that key gaps in scientific knowledge existed concerning the toxicity and human health effects of hazardous substances. To address these gaps, ATSDR was mandated under the Superfund Amendments to initiate a substance-specific applied research program. Specifically, Congress directed, first, that ATSDR and EPA were to jointly rank the most hazardous substances found at Superfund sites; second, ATSDR was to then develop toxicological profiles on the substances identifying what was known about the health effects of these substances and what was not known; and third "For any such substance for which adequate information is not available (or under development), the Administrator of ATSDR, in cooperation with the Director of the National Toxicology Program, shall assure the initiation of a program of research designed to determine the health effects (and techniques for development of methods to determine such health effects) of such substance."
Moreover, the 1986 amendments to Superfund also state "It is the sense of the Congress that the costs of research programs under this paragraph be borne by the manufacturers and processors of the hazardous substance in question, as required in programs of toxicological testing under the Toxic Substances Control Act. Within 1 year after the enactment of the Superfund Amendments and Reauthorization Act of 1986, the Administrator of EPA shall promulgate regulations which provide, where appropriate, for payment of such costs by manufacturers and processors under the Toxic Substances Control Act, and registrants under the Federal Insecticide, Fungicide, and Rodenticide Act, and recovery of such costs from responsible parties under this Act."
In October 1991 ATSDR announced the list of 275 ranked hazardous substances, together with the priority data needs for the top 38 substances. ATSDR is now working to implement this critical research agenda. Before the end of August, ATSDR will transmit to EPA a set of key data gaps for TSCA/FIFRA consideration. We are also working with private industry to establish a voluntary research program. In addition, ATSDR has entered, through Congressional directive, into a program of $4 million of applied research with 8 Historically Black Universities and Colleges that comprise the Association of Minority Health Professions Schools.
ATSDR considers this gaps filling research program to be of great importance. Better scientific data on the bioavailability, human exposure characteristics, substance toxicity, and human health effects of priority Superfund hazardous substances would improve risk assessments for these substances and health assessments of communities around Superfund sites.
Mr. Chairman, this concludes my testimony. I will be pleased to answer any questions.
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