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Congressional Testimony
ATSDR: Public Health Actions and Findings (Update '95)

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 Superfund, Waste Control, and
Risk Assessment
Committee on Environment and Public Works
United States Senate

March 29, 1995

Good morning. I am Barry Johnson, Ph.D., Assistant Administrator of the Agency for Toxic Substances and Disease Registry (ATSDR). I have served as Assistant Administrator since 1986, and my professional background is in toxicology and environmental health. I welcome this opportunity to brief you on ATSDR's public health actions and findings under the Comprehensive Environmental Response, Compensation, and Liability Act, (CERCLA, or Superfund).

My testimony today will update information I provided on May 6, 1993, to the Senate Subcommittee on Superfund, Recycling, and Solid Waste Management. I will provide the committee with what we, and others, have found about the associations between human health and hazardous wastes and the prevention of adverse human health effects resulting from exposure to such wastes.

CERCLA, as amended, mandates of ATSDR a broad, national program of Superfund site health assessments, health investigations, surveillance and registries, applied research, emergency response, health education, and toxicological database development. Our work is conducted in close collaboration with the Environmental Protection Agency (EPA), state health departments, and local health agencies.

As preface, the American public remains quite concerned about the potential impacts of Superfund sites on public health. Since 1991, ATSDR has received more than 4,000 requests for assistance from concerned citizens potentially affected by more than 1,000 sites. Additionally, since February first of this year, we have received more than 45,000 requests for information via the Internet. ATSDR has had direct contact since 1991 with more than 300,000 citizens concerned about Superfund and hazardous substances issues through our public meetings and other site-specific activities.

Serious gaps exist in scientific knowledge about the toxicity, bioavailability, exposure, and human health effects of individual hazardous substances and mixtures of substances released from Superfund sites and during emergency releases. To that end ATSDR, EPA, and private industry are jointly working to fill 117 key data gaps for the first 38 top-ranked hazardous substances released from Superfund sites.

The following statements capsulize our findings to date related to the impact on public health of hazardous waste sites and emergencies related to unplanned releases of hazardous substances:

• Although epidemiologic findings are still unfolding, when evaluated in aggregate (i.e., by combining health data from many Superfund sites), proximity to hazardous waste sites seems to be associated with a small to moderate increased risk of some kinds of birth defects and, less well documented, some specific cancers.

• Health investigations of communities around some individual hazardous waste sites have found increases in the risk of birth defects, neurotoxic disorders, dermatitis, leukemia, cardiovascular abnormalities, respiratory dysfunction, and immune disorders.

• Site remediation doesn't necessarily resolve all public health concerns. An increasing body of scientific evidence indicates that past exposures to hazardous substances can cause latent adverse health effects. Recent findings from the ATSDR exposure registry of approximately 5,000 persons exposed in the past to trichloroethylene (TCE) in drinking water showed adult registrants reporting elevated rates of stroke, liver problems, anemia, diabetes, kidney disease, and skin rashes; speech and hearing impairments were increased in young children. These findings highlight the need for continuing surveillance of populations exposed to hazard substances.

• From what we've learned about 1,309 sites assessed by ATSDR through December 1994, completed exposure pathways (i.e., people were in the path of substances released from sites) were identified at 513 (39%) sites. About 60% of EPA National Priorities List (NPL) sites assessed by ATSDR in fiscal years 1993 and 1994 were found to have completed exposure pathways.

• ATSDR has issued 21 major health advisories on sites considered imminent and urgent threats to public health; those advisories have led to removal actions under EPA's authorities. Seven sites have been placed on the NPL because ATSDR issued a health advisory.

• Of the 136 sites for which public health assessments were conducted and advisories were issued in fiscal years 1993 and 1994, ATSDR classified 54% as health hazards. Historically, 23% of 1,719 public health assessments for more than 1,300 Superfund sites represented a health hazard, according to ATSDR's criteria. Both these figures should be cited with caution, however, because of limitations in our contaminant and human exposure databases.

• ATSDR has completed an analysis of the demographic characteristics of populations around 93% of the current 1,296 NPL sites. Our data, which are based on 1990 census information, indicate that about 11 million people reside within 1 mile of these sites's borders, whose health is potentially affected by exposure to hazardous substances at the site.

• At more than 50% of sites where people are known to be exposed to a contaminant from the site, lead or trichloroethylene, or both, were identified as hazards. At more than one third of these sites, levels of concern of chromium, benzene, arsenic, tetrachloroethylene, cadmium, toluene, 1,1,1-trichloroethane, or methylene chloride were also found. All but two of these substances are known carcinogens or are reasonably anticipated to be carcinogens.

• 60% of ATSDR's public health assessments include recommendations to EPA and states to interdict or reduce current, ongoing exposures to hazardous substances.

• From 1993 data reported by 11 state health departments from almost 4,000 emergency events where hazardous substances were released, there were 16 deaths, 4,063 separate injuries sustained by 2,269 victims, and 496 evacuations of people. The most frequent victims were responders to the event and employees working at a facility.

• Physicians and other health care providers in communities around Superfund sites continue to express a significant need for training and technical assistance in matters of hazardous substances.

I'll now discuss details of these trends. Perhaps the most pressing of the mandates given ATSDR has involved conducting public health assessments at abandoned hazardous waste sites.

Public Health Assessments

Since 1986, the Agency has completed more than 1,700 public health assessments of communities around Superfund sites. The 1986 CERCLA amendments require that ATSDR: a) conduct, within 1 year, a public health assessment of every site placed, or proposed for placement, on the NPL, and b) respond to petitions for health assessments from individuals. The NPL currently numbers 1,296 sites, including 162 federal government sites or facilities.

Public health assessments are ATSDR's principal device for identifying communities that need public health followup. Our public health assessments are conducted using environmental contamination data provided primarily by EPA; health outcome data (e.g., birth defects), which states supply when available; and community-reported health concerns.

Many of ATSDR's public health assessments are conducted by state health departments under cooperative agreements with ATSDR. Currently, ATSDR funds 22 states (encompassing approximately 80% of all NPL sites) to draft public health assessments that are then reviewed and approved by ATSDR staff.

The Agency's public health assessments currently place sites in specific categories of public health concern. Data from the 136 sites assessed in fiscal years 1993 and 1994 indicate that about 5% of sites presented an Imminent and Urgent Public Health Hazard. ATSDR classified 49% of sites as Public Health Hazards, 34% as Indeterminate (sites where key environmental data are lacking to adequately determine if persons are being exposed), 10% as No Apparent Public Health Hazard (sites where past and current exposures have been indicated but where current data indicate those exposures are no longer of public health concern), and 2% as No Public Health Hazard. Ranking and classification of sites are not precise sciences; as databases have improved in quality, so has the ranking and categorization of sites.

ATSDR has compiled the information from its 1,700 public health assessments, 2,500 consultations, and other documents into a unique integrated database, called HazDat. ATSDR has used this database to identify a number of characteristics about Superfund NPL sites. An analysis of 1,309 sites assessed through December 1994 found that pathways of human exposure to hazardous substances were completed at about 40% of sites. For fiscal years 1993 and 1994, this figure increased to 60%, primarily because of improvements in contaminant databases and other types of information.

ATSDR also has been able to make important observations about the types of contaminants released from Superfund sites; the environmental media that are most affected by those contaminants; and the pathways by which people are exposed to contaminants. The top 10 contaminants of concern identified at sites with a completed exposure pathway were these: lead (59% of sites), trichloroethylene (TCE) (53%), chromium (47%), benzene (46%), arsenic (45%), tetrachloroethylene (PCE) (41%), cadmium (39%), toluene (39%), 1,1,1-trichloroethane (32%), and methylene chloride (31%). All but two of these substances are known carcinogens or are reasonably anticipated to be carcinogens.

Contaminants released from sites were most frequently identified in groundwater, followed by subsurface soil, sediment, and surface water.

Using ATSDR's HazDat database, we have found that a hundred or more different toxic chemicals can be found at a single waste site. These chemicals can be found in widely varying combinations in water, soil, and air, and some of the combinations may be much more hazardous than any of the individual chemicals. Therefore, ATSDR is examining the combinations of chemicals that exist at waste sites to identify chemical mixtures that should be studied. As an example of what we have learned from this analysis, we have found that soil with levels of concern for copper, chromium, arsenic, cadmium, or mercury almost always also has lead in high levels (more than 80% of the time). This kind of information is important for designing human epidemiologic investigations and relevant laboratory studies. The National Research Council, using EPA data, estimated in 1991 that about 41 million people reside within 4-mile radii of 1,134 NPL sites. ATSDR has completed an analysis of the demographic characteristics of persons residing around 93% of the current 1,296 NPL sites. We find that 11 million people live within 1 mile of these sites' borders. These people are potentially at risk from exposure to hazardous substances at these sites.

In fiscal years 1993 and 1994, sufficient data were available to indicate the need for health investigations at about 35% of sites, including sites where concern was for current or past exposures to hazardous substances released from the sites. The investigations are examining human exposure and health effects. ATSDR has a backlog of health followups; approximately 15% of followups can currently be completed each year. As I mentioned, ATSDR can be petitioned by an individual to conduct a public health assessment of a site. The Agency has received 394 petitions to date, representing 323 individual sites. An average of 80 petitions are received annually. We are currently accepting about 75% of petitions for conduct of public health assessments or health consultations. About 55% of petitions come from individual or community groups; about 8% come from members of Congress. The large number of petitions received annually is a demanding workload for ATSDR; to put these 80 into perspective, EPA added 23 sites to the NPL in 1991, 30 in 1992.

Health Effects Investigations

Another of the CERCLA mandates requires that we conduct studies of the adverse health effects of exposure to hazardous substances from waste sites. Epidemiologic studies conducted by ATSDR, state health departments, and academic institutions are of two types: a) studies that examine the health of persons around individual sites and b) studies that combine populations around sites and their data for aggregate analysis.

Health investigations help identify persons for whom exposures can be interdicted, add important information about risk factors for diseases and illnesses, identify vulnerable populations on whom to focus prevention activities, determine relationships between exposure and adverse health effects, and help determine or evaluate measures to prevent or mitigate adverse health conditions. Findings from human health studies are also significant material for inclusion in site-specific risk assessments.

Aggregated Site Studies

Investigating the broad picture of the association between hazardous waste sites and public health impact requires combining site populations with common environmental characteristics, thereby increasing the size of the human populations investigated. This aggregating of sites has been used as an investigative method by researchers examining the association between cancer and birth defects rates in areas around hazardous waste sites.

Two sets of investigators have reported an increased frequency of cancers in counties surrounding hazardous waste sites. In 1983, G. Najem reported that age-adjusted gastrointestinal (GI) cancer mortality rates (all sites combined) were higher in 20 of New Jersey's 21 counties than national rates. Within specific sex and race groups, cancer mortality rates in the state during the period 1968-1977 significantly exceeded national rates for cancers of the esophagus, stomach, colon, and rectum. The environmental variables most frequently associated with GI cancer mortality rates were population density, degree of urbanization, and presence of toxic waste disposal sites. Similarly, an EPA study was conducted of 593 hazardous waste sites in 339 U.S. counties of 49 states where analytic evidence showed contaminated groundwater as the sole source of drinking water supply. For each identified county, age-adjusted, site-specific cancer mortality rates for 13 major cancer sites (anatomic) were extracted from U.S. Cancer Mortality and Trends (1950-1979) for white males and females during the decade 1970-1979. Statistically significant associations between excess deaths and all counties with hazardous waste sites, when compared to all counties without hazardous waste sites, were shown for cancers of the lung, bladder, esophagus, stomach, large intestine, and rectum for white males; and for cancers of the lung, breast, bladder, stomach, large intestine, and rectum for white females. Neither the EPA nor the New Jersey studies reported any data bearing on the levels of exposure of these residents, which is a significant limitation.

A New York State Health Department study examined the association between congenital malformations in children and maternal proximity to hazardous waste sites in the state. The study included data for 9,313 newborns with congenital malformations, as recorded in the New York State Congenital Malformations Registry, and 17,802 healthy comparison children. A total of 590 hazardous waste sites in 20 New York counties were selected for analysis of the incidence of malformations. (Waste sites in New York City were excluded, given what were presumed unique sociodemographic and geographic characteristics compared with the rest of the state.) An exposure risk index was created for each respondent within a 1-mile radius of the birth residence. Through statistical analysis, the investigators controlled for several possible confounding variables, including maternal age, race, education, complications during pregnancy, birth weight, length of gestation, and sex of child. It is important to note that other possible confounding factors, such as smoking and alcohol history, maternal and paternal occupational exposures, and maternal nutritional status were not evaluated because of lack of data. Results indicated that maternal proximity to hazardous waste sites may carry an additional risk of approximately 12% of bearing children with congenital malformations. Higher malformation rates were associated with both a higher exposure risk (63% increase in risk) and documentation of off-site chemical leaks (17% increased risk). These results are the subject of follow-up investigation by ATSDR and the New York State Health Department.

ATSDR supported an additional birth defects study by the California Department of Health Services. The department conducted a study investigating the relationship between maternal residence and the presence of hazardous waste sites for the risk of congenital malformations. The study evaluated births between 1983 and 1985; 5,617 births with congenital malformations were evaluated. The study concluded that maternal residence at the time of the child's birth in a census tract with a hazardous waste site, significantly increased the risk of giving birth to an infant with malformations of the heart and circulatory system.

Studies by ATSDR and other researchers indicate that adverse reproductive outcomes may be related to consumption of contaminated drinking water or living in proximity to hazardous waste sites. For example, birth defects and developmental disabilities were evaluated by ATSDR-funded surveillance systems in Iowa, New Jersey, and Washington. These states used birth defects registries and birth records to assess populations potentially exposed to hazardous substances in specific geographic areas. Excess stillbirths, prematurity, low birth weight, cardiac defects, urogenital defects, limb reductions, clubfoot, oral clefts, and neural tube defects may be related to exposures to hazardous substances through contaminated drinking water. Birth defects data from these state surveillance systems will be the subject of additional epidemiologic studies to clarify any associations with hazardous waste sites.

ATSDR has adopted the approach of aggregating sites for the purpose of health evaluation. This approach was outlined in a 1992 report to Congress entitled, The Feasibility and Value of Performing Multisite Epidemiologic Studies for Superfund Sites. An example of this approach is an ATSDR study conducted in four separate geographic areas near mining and smelting sites in Illinois, Kansas, Missouri, and Pennsylvania involving more than 2,200 people. It was found that children living near the sites had higher levels of lead in their blood than children in comparison communities, and that soil lead levels were significantly associated with the increased blood lead levels in the children. As you know, lead has been shown to be particularly harmful to the developing brain and nervous system of young children.

Latent adverse health effects in persons who in the past were exposed to hazardous substances are suggested by findings from ATSDR's National Exposure Registry. Included in the registry are approximately 5,000 individuals with documented exposure to trichlorethylene (TCE). The 5,000 registrants come from 14 sites in Michigan, Indiana, Illinois, and Pennsylvania; 10 of the sites are on the NPL. TCE levels in drinking water ranged from 1 part per billion (ppb) to 19,380 ppb. (The Maximum Contaminant Level for TCE is 5 ppb.) Exposure durations ranged up to 18 years. For essentially all persons on the registry, TCE exposure has stopped following provision of uncontaminated water. Registrants report (through a structured health survey) more health problems compared to respondents to other national health surveys. Some of these problems were reported only by males, some only by females, and some only by specific age groups. The health problems reported in excess of those reported by the general U.S. population included anemia and other blood disorders, diabetes, hearing impairments, kidney disease, skin rashes, speech impairments, stroke, and urinary tract disorders. Some of the health problems reported by registrants are consistent with the toxicology of TCE. However, caution must be exercised when interpreting these health findings. Medical validation studies currently are being conducted of a sample of the 5,000 registry cohort.

Health Studies at Individual Sites

A considerable number of studies have been conducted by Federal, State, and local governments, universities, and private investigators regarding health effects in communities around individual hazardous waste sites. Many of these studies are negative in the sense that statistically significant increases in adverse health effects were not found. Although such findings may represent the true health status of the communities because of limited or no exposure to hazardous substances, the negative findings may also be the result of inadequate sample sizes, inadequate information about exposure to hazardous substances, poor selection of sites studied, or inappropriate health effects studied for the toxicology of the specific substances found at a given waste site.

Some recently completed, peer reviewed, site investigations conducted by ATSDR or state health departments with ATSDR support reported the following results:

Respiratory Illness

At the Brio NPL site in Friendswood, Texas, a study of 744 current or former residents showed increased reports of respiratory and skin problems.

A 1995 study among residents of Forest City and Glover, Missouri, who lived near NPL sites showed an increase in reports of respiratory problems and decreased pulmonary function, especially among nonsmoking women.

Findings from an ATSDR study of residents living near a former hazardous waste incinerator in Caldwell County, North Carolina, show an increased prevalence of respiratory disease in the target population. Follow-up biomarker testing that found decreased pulmonary function among residents living near the site verifies these symptoms.

Cancer and Immune System Function

Testing of approximately 6,000 persons who live near 10 hazardous waste sites and were potentially exposed to volatile organic compounds showed an increased rate of people having an unusual production of abnormal blood cells that has been associated with chronic lymphocytic leukemia.

Findings from an ATSDR cross-sectional, symptom- and disease-prevalence study of 700 persons exposed to volatile organic compounds in drinking water reveal an increased prevalence of the debilitating disease erythematosus lupus.

Birth Defects and Reproductive Disorders

A study among Texarkana, Texas, residents showed that persons living near an abandoned wood treatment facility had more difficulty becoming pregnant and had fewer pregnancies than a comparison population not living near the site.

In an ATSDR-funded study, investigators reported the occurrence of birth defects in the children of women living near 700 hazardous waste sites in California. Analysis shows that children of women living near sites where exposure to the solvents toluene and xylene was likely had greater than twice the typical rate of neural tube birth defects, such as spina bifida and anencephaly.

Findings from an ATSDR-funded study of minority women living near sites in California where exposure to semi-volatile organic chemicals, pesticides, and heavy metals was likely shows elevated rates of limb reduction defects, central nervous system defects, and heart defects in their children compared to the rates of such defects in the children of minority women not living near hazardous waste sites.

Near the Lipari NPL site in New Jersey, a study by the New Jersey State Health Department (funded by ATSDR) showed an indicator of intrauterine growth retardation resulting in fetuses that are small for their gestational age in children born to women living near the site. An evaluation of the occurrence of this condition from 1961 to 1985 showed that rates were higher in residents living closer to the site.

Neurologic Problems

An ATSDR study of residents living near a former hazardous waste incinerator in Caldwell County, North Carolina, found increased neurologic symptoms in residents living near the incinerator site.

When compared with the expected rates of illness among the U.S. population, children from ATSDR's National Exposure Registry who were exposed to trichloroethylene through contaminated drinking water had higher rates of speech and hearing impairment.

A comprehensive review of the published literature on the public health implications of hazardous waste was conducted by the National Research Council. This review concluded: In spite of the complex limitations of epidemiologic studies of hazardous-waste sites, several investigations at specific sites have documented a variety of symptoms of ill health in exposed persons, including low birth weight, cardiac anomalies, headache, fatigue, and a constellation of neurobehavioral problems. It is less clear whether outcomes with a long delay between exposure and disease also have occurred, because of complex methodological problems in assessing these outcomes. However, some studies have detected excesses of cancer in residents exposed to compounds, such as those that occur at hazardous waste sites. A more recent study of the scientific literature concerning hazardous waste and human health effects was sponsored by the Chemical Manufacturers Association (CMA) this year. That study identifies a number of shortcomings in the studies reviewed. The principal shortcoming identified by the CMA reviewers was too limited knowledge about levels of exposure of community residents to substances released from waste sites.

ATSDR's experience shows that adverse health effects of hazardous substances released from sites have occurred in some communities. The prevalence of adverse effects is unknown because of limitations in toxicologic knowledge, environmental databases, and environmental epidemiology practices.

Health Studies of Remediation Workers

In addition to concern for the health of communities potentially affected by the release of substances from hazardous waste sites, care must be exercised that the workers who remediate (i.e., clean up) the sites are not harmed by their work. The removal of soil or water contaminated with toxic substances clearly presents the potential for adversely affecting the health of clean-up workers if the necessary precautions are not taken.

As an industry, cleanup of hazardous waste sites is relatively new in the United States, but one that involves large numbers of workers. Given the recent introduction of site-specific work, there is only a very limited scientific database on any potential health effects associated with such work. According to one source, clinical and research findings from clinical centers performing health surveillance examinations on hazardous waste workers have not shown remarkable health abnormalities related to the workers' activities. From a public health perspective, this is a very desirable outcome. However, the investigators caution that the lack of any health problems in hazardous waste workers may be due to the fact that most of the workers examined had performed feasibility (i.e., inspection and assessment) work, not actual remediation of sites.

I am pleased to note that ATSDR and the Health and Safety Fund, which is a joint project between the Laborers International Union of North America and site remediation contractors, have jointly developed a health surveillance program for hazardous waste remediation workers. This system will eventually contain medical information on about 5,000 remediation workers. The data will be evaluated periodically for any evidence of adverse health effects in groups of workers.

Exposure Studies

Concern for public health effects of hazardous substances occurs when exposure in humans exceeds safe levels. A series of studies conducted by ATSDR has documented human exposure to contaminants at some Superfund sites, but no exposure at other sites. This human exposure information is critical, and can best be verified through biologic sampling.

Examples of ATSDR-conducted studies that document human exposure to contaminants from waste sites include these:

The importance, and difficulty, of relating environmental contamination levels with human exposure levels is exemplified by the work ATSDR has done in conjunction with the Centers for Disease Control and Prevention (CDC) and the Panhandle Health District in Idaho to conduct blood lead surveillance of children exposed to lead from a smelter. The smelter closed in 1982 and the area around it is an NPL site. Lead in soil and dust were the principal exposure routes. Through surveillance and intervention efforts, children's mean blood levels have declined steadily since 1974. However, in 1992, blood lead levels in about 26% of children still exceeded 10 micrograms/dL. Efforts are ongoing to reduce all children's blood lead levels to below 10 micrograms/dL, the current CDC action level for lead.

A study of the Mohawk Tribe in New York documented that women who consumed local fish from polychlorinated biphenyl (PCB)-contaminated waters had significantly higher concentrations of PCBs in their breast milk.

In Fond du Lac, Wisconsin, Native Americans who consumed fish from water contaminated with mercury were found to have higher levels of mercury in their blood than people who did not consume fish.

An exposure study by the New Mexico Department of Health among residents near the Billing Mine Superfund site in Socorro found higher blood lead levels in persons living near the site.

Human exposure studies of persons residing near other uncontrolled waste sites has shown that little to no exposure to hazardous substances was occurring:

The results of biologic testing of residents living near the ASARCO Smelter site in Everett, Washington, showed that the vast majority of participants in the study did not have current exposure to arsenic. This study, done in cooperation with EPA, supported the conclusion that some of the interim actions for reducing exposure at the site had been effective, and that relocation of residents was unnecessary.

An ATSDR study of human exposure to PCBs in Monroe County, Indiana, found that in spite of the potential for exposure to PCB-contaminated media, the results of their serum PCB tests showed that individuals living in the community were generally not at risk of current exposure to PCBs.

A study of persons living near contaminated areas in American Samoa showed no association between residence in target areas and increased levels of site-related contaminants in their bodies.

A study of people who were exposed to contaminated drinking water in communities surrounding the Rocky Mountain Arsenal site in Colorado showed no significant increases in levels of mercury and arsenic in urine.

Emergency Response and Consultations

I turn now to what we have learned about the other type of site addressed under Superfund the emergency release of hazardous substances. ATSDR has implemented an active state-based hazardous substances emergency events surveillance system to describe the public health consequences associated with hazardous substance releases. As a result of our activities, the ability of participating states to respond to an emergency involving hazardous substances has been significantly improved.

Fourteen states are collecting data on the nature and impact of emergency releases of hazardous substances. Information reported by 11 of these states on nearly 4,000 events in 1993 indicates the following trends:

12% of all emergency events involving exposure to hazardous substances resulted in injuries.

4,063 separate injuries (including 16 deaths) were sustained by 2,269 victims.

The most frequently reported injuries were respiratory irritation, eye irritation, nausea, and headache, followed by chemical burns and trauma. The most frequent victims were responders to the event and employees working at a facility.

496 emergency events required the evacuation of people living nearby.

A special kind of health consultation is the Public Health Advisory. It is a statement of concern from the ATSDR Administrator to the EPA Administrator. ATSDR has issued 21 public health advisories, leading to placement of 7 sites on the NPL.

As examples of health advisories, in November 1990, ATSDR issued a public health advisory informing EPA, the Navajo Nation, the Indian Health Service, and other federal and New Mexico state agencies of a potential significant environmental hazard to human health on Navajo land near Bluewater, New Mexico. ATSDR was concerned that the presence of uranium-containing radioactive mine wastes, areas potentially contaminated with heavy metals, and many physical hazards could result in adverse human health effects in residents of the areas. Potentially affected persons included 25 individuals in 2 extended families living in the immediate vicinity and approximately 100 additional persons within a 3-mile radius. As a result of this public health advisory, EPA completed an emergency removal of uranium-containing waste ore from the site, reducing radiation exposure by about 80%.

As a second example, in 1991, ATSDR, in support of EPA, issued a public health advisory on a potential significant environmental hazard to human health in the vicinity of Austin Avenue, Lansdowne, Pennsylvania. The contaminants of concern included radium, radon, and asbestos in a warehouse and residence. In conjunction with the release of the public health advisory, EPA, at the advice of ATSDR, relocated two families and initiated whole body radiation counts on them to determine if they had been internally contaminated by radium at the sites. As a result of this public health advisory, EPA surveyed an area extending in a 2-mile radius from the Austin Avenue site (encompassing more than 12 square miles of metropolitan Philadelphia, Pennsylvania) and identified 21 additional sites with elevated radiation readings. In 1993, ATSDR issued a public health advisory concerning an area of Stratford, Connecticut. City and state authorities had found widespread contamination of school play areas and residential properties because contaminated soil had been used as fill material. The contaminated soils contained large concentrations of lead, PCBs, and asbestos. ATSDR, working with EPA and state and local health and environmental agencies, implemented a number of public health interventions in 1994. These included a voluntary blood lead testing program, in-home dust sampling, physician education on hazardous substances, and EPA's proposed placement of the Stratford site on the NPL.

Toxicological Databases and Data Gaps

The 1986 CERCLA amendments [§104(I)(2)] require ATSDR and EPA to jointly rank, in order of health importance, hazardous substances released from waste sites. The agencies have agreed on a list of 275 Superfund Priority Hazardous Substances. The first 10 substances on the list are lead, arsenic, mercury, vinyl chloride, benzene, cadmium, PCBs, chloroform, benzo(a)pyrene, and trichloroethylene.

ATSDR is directed by CERCLA [§104(I)(3)] to prepare a Toxicological Profile for each Priority Hazardous Substance. We have developed 200 profiles to date; these profiles are up-to-date compilations of all that is known about the health effects of these substances.

These profiles also identify key data gaps in scientific knowledge about hazardous substances. For example, exposure to what levels of mercury will result in an acute health effect? Does drinking benzene-contaminated water cause birth defects? Does eating fish contaminated with PCBs cause illness? Does long-term exposure to zinc cause cancer?

As directed by CERCLA [§104(I)(5)], ATSDR, in cooperation with EPA and the National Toxicology Program must evaluate the adequacy of scientific data for each of the 275 prioritized substances. Key gaps in scientific knowledge are to be filled through referral to EPA's authorities under the Toxic Substances Control Act and other mechanisms. The 117 key data gaps for the first 38 substances on the Priority List of Hazardous Substances were published in 1992. CERCLA directs that ATSDR work with EPA, National Toxicology Program, and industry to initiate applied research to fill identified data gaps. ATSDR has referred 60 key data gaps to EPA for handling under its Toxic Substances Control Act authorities. Some key data gaps are being filled by funding from ATSDR, as directed by Congress, through research grants to academic institutions in the Association of Minority Health Professions Schools and to academic and state health departments in support of health research mandated by the Great Lakes Critical Programs Act. Some data gaps will be filled voluntarily by private industry through arrangements with ATSDR.

Health Education

Turning to another of our mandates, CERCLA [§104(I)(14)] directs ATSDR to develop educational materials and provide training for medical colleges, physicians, and other health professionals. To this end, we have developed a series of monographs entitled Case Studies in Environmental Medicine to inform health care professionals of health effects caused by hazardous substances in the environment. Twenty documents are currently available; another 15 are in various stages of development. These self-instructional exercises in environmental medicine are designed to guide primary care practitioners through the diagnosis and treatment of illness in persons exposed to hazardous substances in the environment. The documents are prepared and peer reviewed with the assistance of physicians and other health care professionals, including representatives of a number of professional medical societies and associations.

Since 1986, as part of our educational efforts, we have:

• provided training to more than 30,000 health professionals,

• distributed more than 140,000 copies of the Case Studies,

• provided training to more than 400 minority health professionals, and

• distributed to physicians and hospitals more than 60,000 copies of medical management guidelines for use in responding to emergency events.

Key partners in our work are EPA and state and local health departments. One main purpose of our support to state and local health departments is to improve the ability of health agencies to respond to community health concerns. I refer to communities around Superfund sites and other areas of pollution. These communities' legitimate health concerns need the coordinated response of government at all levels.

In 1986 when Congress reauthorized Superfund, it was clear that they strengthened the statute's health section, and it was equally clear to ATSDR that Congress envisioned a partnership between states and ATSDR in implementing these health provisions. In 1987, the Agency committed itself to a goal of building or enhancing state health departments' capacity in environmental health. From fiscal year 1987 through 1994, we provided about $62,600,000 in funds to 36 states through a series of cooperative agreement programs. This figure represents approximately 18% of ATSDR's total budget during this period, a substantial figure given other budgetary demands on the Agency.

We have also continued to strengthen our focus on community involvement as an integral part of conducting site-related activities. ATSDR and cooperative agreement state personnel directly contact annually as many as 30,000 members of communities near hazardous waste sites. ATSDR also is increasing its use of public availability sessions, informal, drop-by meetings at which community members can meet one-on-one with ATSDR staff to discuss health and site concerns. Other site-specific community involvement activities that we have found useful include small group briefings for key community leaders, a practice that enables ATSDR to solicit information from grassroots leaders about how best to interact with their constituents and address their concerns, and to provide up-to-date information about ATSDR activities in their community. Let me also note that ATSDR is one of eight agencies comprising the Public Health Service; we are the principal federal public health agency involved with hazardous waste issues. Our headquarters are in Atlanta. The ATSDR Administrator also serves as the Director of the Centers for Disease Control and Prevention (CDC). Some have suggested merging ATSDR with CDC. As a technical observation, we would note that virtually all of ATSDR's administrative and substantial technical support come from CDC. Further, ATSDR and CDC both have complementary expertise in epidemiology, laboratory, surveillance, and applied research.

Summary

People living around Superfund sites continue to express concerns that their health may be impacted. Since 1986, when CERCLA was reauthorized, ATSDR and state health departments have learned a great deal about what substances are released from sites and have developed mechanisms to assess the health hazard potentially posed by individual sites. A considerable body of information exists that shows community populations have been exposed to substances released from sites. Moreover, an increasing body of epidemiologic studies indicate that some sites, when considered in the aggregate, have an increased risk of birth defects and adverse reproductive effects and, potentially, effects on other organ systems. Additionally, for some individual sites, adverse health effects have been reported or measured. For some sites investigated, health impacts on community populations are not evident. Also, the Chemical Manufacturing Association review of health studies mentioned earlier identified the lack of knowledge about exposure as the major problem in studies about hazardous waste and human health effects.

As more sites are investigated, health officials will sharpen their methods to determine which sites are most likely to be sources of exposure for community populations. During the past 5 years, analytic methods have been developed that will help health officials measure human exposure to substances released from sites. Given the nature of these health findings, interdiction of human exposure to substances from sites through removal or remediation actions is clearly consistent with the practice of public health.

ATSDR's work with state health departments also indicates that emergency events involving releases of hazardous substances are frequent and represent a serious challenge to health and environmental officials. Extra effort will be required to reduce the number and consequences of unplanned releases of substances. Maintaining an active surveillance system for emergency events will be necessary if we are to gauge the progress of educational efforts intended to reduce the impact of such events.

Mr. Chairman, this concludes my testimony. I will be pleased to answer questions.

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