Implementation of Superfund's Health-Related Provisions by the Agency for Toxic Substances and Disease Registry

Barry L. Johnson

Barry L. Johnson, Ph.D., is Assistant Administrator of the Agency for Toxic Substances and Disease Registry and Assistant Surgeon General, Public Health Service, U.S. Department of Health and Human Services, Atlanta, Georgia.

[20 ELR 10277]

When the Superfund Amendments and Reauthorization Act of 1986 (SARA)¹ was enacted in October 1986, the Agency for Toxic Substances and Disease Registry (ATSDR) was still in the early stages of development as a new entity in the Public Health Service.² Staff had to be recruited; an organizational structure had to be developed; working arrangements with the Environmental Protection Agency (EPA), the Centers for Disease Control (CDC), and the states had to be defined and implemented; and a host of policy decisions had to be resolved. None of this could be accomplished overnight; indeed, the Agency is still maturing. Notwithstanding these challenges, ATSDR has accomplished much in the last three years.

This Dialogue is ATSDR's response to the article by Martin R. Siegel entitled "Integrating Public Health Into Superfund: What Has Been the Impact of the Agency for Toxic Substances and Disease Registry?"³ Siegel's article refers to ATSDR's programs under the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA or Superfund)⁴ and comments on the Agency's fulfillment of its Superfund responsibilities since passage of SARA four years ago.

ATSDR's Accomplishments

Since SARA's enactment, ATSDR has accomplished the following:

* Established policies, procedures, and working relationships with EPA and the states to complete a mandate of December 1988 to conduct health assessments for 951 sites on the National Priorities List (NPL). ATSDR has completed an additional 200 health assessments to date.

* Determined that approximately 85 percent of the 1,151 sites for which health assessments have been conducted involve releases of hazardous substances; that about 15 percent of the sites potentially require further public health review by ATSDR (e.g., health advisory or epidemiological studies) and that the remainder either require more environmental contamination data or do not present current public health threats.

* Established a disease surveillance program linked to environmental databases that builds on health outcome databases funded in 10 state health departments.

* Undertook development of policies and procedures for registries of persons exposed to select hazardous substances. Registries for persons exposed to trichloroethylene, dioxin, and other substances now include 16 NPL sites and two non-NPL sites.

* Provided an average of approximately 4,000 consultations per year on the health implications of hazardous substances, including approximately 1,000 each year on emergency releases of hazardous substances.

* Developed with EPA a priority list of 225 Superfund hazardous substances.

* Developed the format and procedures for producing ATSDR Toxicological Profiles and released 80 profiles that describe the toxic properties and human health effects of 94 hazardous substances. As required by SARA, five profiles have been updated. By October 17, 1990, 30 more profiles covering 36 hazardous substances will be released.

* Developed and published criteria for determining research needs for entries on the priority list of hazardous substances.

* Implemented a comprehensive health and medical education program concerning hazardous substances.

* Prepared and submitted to Congress a comprehensive report on the nature and extent of childhood lead poisoning in the United States.

* Prepared and released for public review a comprehensive draft report to Congress on the health impact of medical waste.

[20 ELR 10278]

* Established a Board of Scientific Counselors to review ATSDR's scientific studies, science policies, and the effectiveness of the Agency's scientific base.

Specific Programs

SARA added many specific, health-related activities to ATSDR's responsibilities under CERCLA.

Site-Specific Activity

SARA required health assessments of nearly 1,000 individual waste sites. Since 1987, ATSDR has developed health assessment procedures, health studies policies, and state-based cooperative agreements in support of site-specific activities.

* Defining Health Assessments. Although CERCLA did not mention health assessments, additions to § 3019 of the Resource Conservation and Recovery Act (RCRA) define what they should consider.⁵ When SARA expanded RCRA's definition of the health assessment and provided guidance on its purpose and form, it left the responsibility to develop policies and procedures to ATSDR. In light of this responsibility, ATSDR recruited and trained health assessment staff. ATSDR also developed policies and procedures on how to review environmental databases and how to format, review, and distribute the reports. Lastly, ATSDR promulgated final regulations for health assessments and health effects studies.⁶ These regulations contain key definitions and procedures that the Agency and its agents will follow in conducting health assessments. All this took place while the statutory time limit directing ATSDR to produce 951 health assessments by December 10, 1988, was running down.

* Completing the Assessments. Once these procedures were established, SARA required ATSDR to conduct a health assessment for all 887 sites on or proposed for the NPL at the time SARA was passed. In addition, SARA mandated that ATSDR complete a health assessment within one year for every new site proposed for inclusion on the NPL. All told, ATSDR was required to prepare health assessments for 951 sites between October 1986 and December 1988.

Because of the magnitude of the effort needed to prepare 951 health assessments in the time allowed, it became clear in 1987 that ATSDR would need assistance. One possibility was to contract outside the Agency for the health assessments. Although private sector contractors could have assumed the responsibility for all or much of the health assessment workload, ATSDR elected not to take this route. It was, and still is, the Agency's conviction that health assessments should be conducted by agencies directly accountable to the public. Therefore, ATSDR turned to state health agencies for help in performing health assessments. This achieved the goal of involving only public agencies in conducting health assessments and also gave ATSDR an opportunity to build or enhance environmental health capacity in state health departments through cooperative agreements. The Agency now has cooperative agreements with 23 states to conduct health assessments at NPL sites. Under cooperative agreements, ATSDR and the states completed health assessments for 951 NPL sites before the December 10, 1988, statutory date.

* The Preliminary Health Assessment. Trying to meet the December 10, 1988, deadline for 951 health assessments placed ATSDR in a difficult position. The schedule under SARA for conducting health assessments was ahead of EPA's schedule for conducting remedial investigations (RI), since SARA states that the health assessment should be completed before completion of the RI. Thus, the in-depth data needed for completing full health assessments would not be available in time to meet the deadline. Therefore, about one-half of the 951 assessments were conducted as preliminary health assessments. These assessments are not based on environmental data from an EPA in-depth remedial investigation/feasibility study. They are labelled "preliminary" to notify the public that they are based on fewer data than are full health assessments. Preliminary health assessments are based on the best data available to ATSDR at the time; they are as complete and thorough as allowed by extant environmental contamination data. Thus, the preliminary health assessment was not an expedient for meeting the SARA mandate, but a conceptual model that evolved in 1987 once ATSDR discovered the limitations of the environmental databases.

Some of the 951 health assessments are still in draft form, and some will remain that way for a while longer. That is because ATSDR has reordered its priorities to address the considerable backlog of petitioned health assessments and to complete other activities set aside during the push to complete assessment of the 951 sites. The Agency has reviewed each of these "draft health assessments" and is assured their final form can be delayed until time and resources permit.

ATSDR, EPA, and the states find the preliminary health assessment to be a useful public health instrument. ATSDR intends to use the preliminary health assessment in its first evaluation of sites added to the NPL or brought to its attention by petition. This approach allows ATSDR to be involved at sites and in affected communities very early in the queue of remedial activities. EPA uses preliminary health assessments to influence priorities for site investigation efforts, and ATSDR also uses preliminary health assessments to set priorities for future actions and follow-up public health activities, such as health advisories.

The most prudent approach for health assessments is to conduct preliminary health assessments for all sites added to the NPL and for petitioned sites. When more complete environmental data become available, full health assessments are then performed for the sites in their order of priority for public health importance. This second in-depth health assessment ensures ATSDR an opportunity to review records of decision (RODs) and should provide a useful final public health check on individual sites.

* Petitions. SARA permits individuals or licensed physicians to petition ATSDR to conduct a health assessment of a site of concern.⁷ To date, ATSDR has received 77 petitions [20 ELR 10279] for health assessments. During 1989, the Agency recruited staff to respond to these petitions. Every petition for a health assessment has now been reviewed, the petitioner has been contacted, and efforts are under way to conduct those health assessments for which supporting data are available. Because some people may petition ATSDR to conduct health assessments because they have lost confidence in state and local authorities, ATSDR has decided to conduct petitioned health assessments using Agency staff whenever appropriate.

* Federal Facilities. Most federal facilities on the NPL are currently being evaluated by preliminary health assessments and health consultations. No full health assessment is complete for any federal facility because there have been no interagency agreements between ATSDR and the responsible federal agencies. However, an ATSDR-funded health effects study of residents who reside near Rocky Mountain Arsenal in Colorado is complete. Although agreements with the Department of Defense and the Department of Energy are nearing completion, no resources have been transferred to ATSDR to enable it to undertake the program of health assessments of federal facilities.

* The Impact of ATSDR's Health Assessments. EPA finds ATSDR's health assessments useful in influencing priorities for site investigations. In particular, health assessments have been used to justify funding of interim intervention activities, such as fencing sites or providing alternative water supplies, while remedial investigations/feasibility studies were under way. Moreover, in fiscal year 1990, EPA began using health assessments to prioritize funding for cleanup activities at NPL sites. EPA and the states often use health assessments to provide community groups and concerned citizens with health information on specific sites. Because health assessments evaluate the entire site, including both chemical and physical hazards, community groups find them beneficial in understanding the complete "health picture." ATSDR recently used the health assessments to recommend health advisories for four sites, thereby placing them on the NPL or requesting EPA to initiate immediate cleanup activities to protect the public health. In addition, the health assessments help ATSDR identify sites for inclusion on the Agency's national exposure registry and for epidemiologic investigations.

* ATSDR's Goals. Although the health assessment program has already contributed significantly to Superfund objectives, ATSDR is not satisfied with some aspects of the program and is working to improve it in several ways. ATSDR places high priority on including more health data in its health assessments. Specifically, the Agency will try to obtain health data such as tumor registry and birth defects data from state, local, and private sources whenever applicable and available for a given site. ATSDR will try to elicit more information on the health concerns of community groups and local health care providers by meeting with them. It will also provide the draft health assessments to the public for review and comment before preparing them in final form. These kinds of changes will help fulfill the goals of providing the Agency and the public with greater involvement and awareness in the Superfund process and drawing a more accurate picture of the public health impact of individual sites.

Epidemiology and Health Surveillance

The heart of citizens' concerns about hazardous substances released from waste sites is their potential impact on human health. The ATSDR epidemiology and health surveillance program is geared to respond to such concerns. The Agency has determined that a phased approach toward investigating health effects is preferable for most waste sites. The sites are identified through ATSDR health assessments. Pilot studies, which are either exposure assessments or disease and symptom prevalence evaluations, are usually the first epidemiological response taken for populations around high priority sites. Full epidemiological studies are conducted when exposure or symptom prevalence data so indicate. ATSDR currently has 28 pilot studies in progress or completed and 14 epidemiological investigations in various stages of completion.

ATSDR's surveillance program currently consists of funding for 10 state-based disease reporting systems. ATSDR funds reports of chronic diseases (e.g., cancer, heart disease) and adverse reproductive outcomes (e.g., birth defects, low birth weights, developmental disorders) that states collect under cooperative agreement with the CDC. The experience gained from these state programs will be important for health surveillance programs around individual waste sites.

ATSDR actively supports research by the National Academy of Sciences (NAS) in its assessment of biological markers to determine human exposure to hazardous substances or to assess organ system damage. A cooperative agreement program between NAS and ATSDR resulted in reports from the Academy on biological markers for pulmonary system toxicity and reproductive system toxicity. Other NAS projects include research on biological markers in immunotoxicology and neurotoxicology and the assessment of low-level exposure to lead in the environment. ATSDR applies recommendations from NAS in the conduct of its epidemiology and surveillance program.

ATSDR is beginning to assess the impact of its pilot studies and epidemiological investigations. The Agency estimates the pilot studies may have affected 42,000 persons in the involved communities. The epidemiological investigations potentially affected approximately 5 million people.

National Exposure Registry

CERCLA directs ATSDR to establish a national registry of people exposed to toxic substances. This directive was retained in SARA, which added a provision that health assessments could be linked to the development of exposure registries for individual sites.

SARA's directive to establish a national registry of persons exposed to toxic substances presented ATSDR with several challenges in 1987. The first question was: "What is the purpose of a national exposure registry?" After conducting a national workshop in March 1987 to discuss the concept of the registry, the Agency held three regional public meetings. The consensus from all these meetings was that ATSDR should establish a national exposure registry, [20 ELR 10280] composed of multiple chemical-specific subregistries, for two purposes. First, subregistries of people exposed to priority hazardous substances could serve as valuable resources for researchers in defining health risks. Second, the subregistries could provide communication links between the government and individual registrants when information about a particular hazardous substance needs to be distributed.⁸

Cost is a major consideration in establishing a national exposure registry. Experience from state-based exposure registries has shown that about $ 180 is required per person to establish a specific exposure registry, with a $ 50 per person annual maintenance fee. This covers the expense of establishing a registry, maintaining the records, and keeping records current by periodic contact with each registrant. Another consideration is the ethical problem of starting a long-term registry program with funding made indefinite by uncertainties such as reauthorization of legislation and budget exigencies. ATSDR has addressed this ethical concern by informing each registrant of the funding uncertainties. To date, registrants have not expressed concern about this arrangement.

ATSDR currently has several exposure subregistries in progress. The Agency is completing a subregistry of approximately 4,500 persons exposed to trichloroethylene (TCE) in private well water, resulting from contaminated groundwater supplies. This TCE subregistry consists of the names of persons who live near Superfund sites in Illinois, Indiana, and Michigan. It should help researchers studying the possible chronic health effects associated with long-term exposure to low concentrations of TCE. The Agency is also supporting a subregistry of Missouri residents and two subregistries of workers exposed to dioxin.

In addition, ATSDR is currently working with New Jersey authorities and a community group to develop a voluntary tracking system for persons who live near the Lipari landfill, the top-ranked site on the NPL. This tracking system will provide ATSDR with valuable experience in the possible use of voluntary enrollments developed by community groups. ATSDR's experience with the TCE subregistry shows that the public strongly endorses voluntary tracking. The response rate of the persons contacted for enrollment in the TCE subregistry exceeds 99 percent. The registrants expressed considerable interest in the adverse health effects that may follow contact with TCE and express support for being kept apprised of findings pertaining to the toxicity of TCE. ATSDR currently has exposure registries at 16 NPL sites and two non-NPL sites. Other subregistries are under ATSDR review for persons exposed to different priority hazardous substances. The ATSDR Board of Scientific Counselors recently reviewed and endorsed six hazardous substances for possible use in developing individual registries. The substances are benzene, chromium, cyanide, mercury, pentachlorophenol, and DEHP (di(2-ethylhexyl)phthalate). The Agency's budget for fiscal year 1991 will determine which, if any, of these substances will be the subject of exposure subregistries.

Priority Substances and Toxicological Profiles

SARA contains a plan to fill significant data needs for priority hazardous substances. The statute requires ATSDR and EPA to jointly rank hazardous substances identified at NPL sites by toxicity, frequency of occurrence, and potential for human exposure. The list now numbers 225 substances in priority groups of 25 substances each.⁹ After releasing the list, ATSDR has found deficiencies in the data supporting a few of the substances. Therefore, ATSDR intends to review the list to ensure its validity. Its plan is to release a draft list of 225 substances for public review in August 1990.

SARA requires ATSDR to prepare a toxicological profile for each substance on the priority list of hazardous substances. ATSDR faced some conceptual and procedural challenges in developing a new toxicological document. Foremost was the question: "Who are the audiences for the profiles?" Following discussions with EPA and state health agencies, ATSDR concluded that the primary audiences should be state agencies, health professionals in government (e.g., ATSDR and state health assessors), the private sector, and community groups concerned with hazardous waste sites.

ATSDR concluded that the audiences would be interested principally in health information about the individual hazardous substances. Therefore, in accordance with advice from the Association of State and Territorial Health Officials, the documents begin with health information, rather than chemical, physical, or manufacturing information. For example, the Public Health Statement, developed to serve the general public, constitutes the first section of each profile and contains a description in nontechnical language of what is known about the toxicity and human health effects of the substances under discussion. State and local agencies find these statements extremely useful and disseminate them at public meetings.

Requests for copies of Toxicological Profiles have been numerous. More than 120,000 copies have been distributed. ATSDR believes that two policy decisions facilitated their wide acceptance. All documents are peer reviewed while in draft form, and the draft documents are made available to the public for review and comment. Input from both reviews is evaluated and incorporated where appropriate. These two reviews ensure, to the greatest extent possible, that the documents are accurate and complete.

Substance-Specific Research

The ATSDR Toxicological Profiles identify gaps in knowledge for priority hazardous substances. Using this information, ATSDR, EPA, and the National Toxicology Program (NTP) must decide which gaps are most important for establishing safe levels of human exposure to individual substances. Working with EPA and NTP, ATSDR developed criteria to determine which gaps should be filled by directed research.¹⁰ ATSDR has identified the research needs for four pilot hazardous substances: isophorone, phenol, carbon tetrachloride, and chloroethane. Description [20 ELR 10281] of these data needs will be published in the Federal Register for public review in the near future.

SARA requires ATSDR's program of substance-specific research to be coordinated with the testing program directed by the Interagency Testing Committee (ITC) and with provisions of both the Toxic Substances Control Act (TSCA) and the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA). In addition, SARA stipulates that EPA develop cost-recovery regulations in support of the research program. In response to these directives, ATSDR initiated efforts with EPA to determine how to coordinate research program with TSCA and FIFRA. A representative from ATSDR was added to ITC to coordinate research activities with that committee's review of toxicants for testing. To date EPA has not developed cost-recovery regulations.

ATSDR postponed development of the substance-specific research program until it was satisfied with its Toxicological Profiles. The profiles contain critical reviews of the toxicological properties and human health effects of priority hazardous substances. These profiles are then used to determine significant knowledge gaps, which, in turn, are to be filled by research. Because the profiles were new documents, their development had to precede the development of the substance-specific research effort.

ATSDR designed its substance-specific research program around the needs of health assessors. That is, the program takes into account the importance of exposure data as well as toxicity and human health data. ATSDR intends to use the Toxicological Profiles to guide the development of scientific knowledge that can be applied in health assessments and health investigations. A program of this kind must necessarily be coordinated with other organizations conducting environmentally oriented research. Indeed, such mandated coordination is a strength of the Superfund health provisions.

Health Education

SARA directs ATSDR to "assemble, develop as necessary, and distribute to the States, and upon request to medical colleges, physicians, and other health professionals, appropriate educational materials (including short courses) on the medical surveillance, screening, and methods of diagnosis and treatment of injury or disease related to exposure to hazardous substances."¹¹ ATSDR is implementing this directive in several ways.

A series of environmental case studies was developed for physicians and medical educators. Each study concerns a specific hazardous substance. Human health effects are described and developed for clinicians. Each draft case study is extensively reviewed by specialists in emergency medicine and family medicine, pediatricians, and members of other medical specialties. Fifteen draft case studies are now available. They will be disseminated to medical societies and other outlets for use by primary care providers.

ATSDR also works with the Association of Occupational and Environmental Clinics. This confederation of 30 clinics with 160 individual members is staffed with specialists in occupational and environmental medicine. ATSDR funded educational programs undertaken by the Association. Through this group, ATSDR will obtain guidance on meeting the needs of clinicians and medical providers in relation to hazardous substances.

The Agency has several other health education projects under way. For example, through an arrangement with the Emergency Response Center in Jefferson County, Kentucky, ATSDR funded the training of 1,192 persons in the protection of public health from emergency release of hazardous substances. Follow-up of trainees indicates they are better able to respond to chemical emergencies. They know how to better protect both their staffs and the public at large.

In 1988, ATSDR initiated a Clinical Fellowship program in environmental medicine. The program provides annual stipends to persons in accredited clinical medicine residency programs. ATSDR supports eight Clinical Fellows. The Agency believes this fellowship program will help fill a key personnel need — persons with specialty credentials in environmental medicine.

Reports to Congress

Since SARA's enactment, the Agency prepared two major environmental public health reports under statutory directives. One report addresses the nature and extent of lead toxicity in young children.¹² The other report, being prepared under a provision in the Medical Waste Tracking Act of 1988,¹³ covers the public health impact of medical waste.

SARA directed ATSDR to conduct a study on the extent of childhood lead toxicity nationwide and to deliver a report to Congress by March 1, 1987. However, administrative difficulties and the time needed to collect and evaluate data for the report made this impossible. The report was completed and delivered to Congress in July 1988. It is a comprehensive statement on the severity of lead toxicity and the large numbers of children who risk long-term adverse health consequences. More than 4,300 copies of the report have been distributed to states, local health agencies, pediatricians, and government agencies. Congress used it when enacting the Lead Removal Act of 1988, which mandates the removal of lead-containing water coolers and fountains from schools. Additional federal legislation to direct the abatement of lead from houses and discontinued use of lead-based solder is under consideration.

ATSDR is preparing a second report to Congress on the public health implications of medical waste. The appearance of medical-related waste on ocean beaches during the summer of 1987 led Congress to enact the Medical Waste Tracking Act of 1988. The Act requires the Agency to prepare a report on medical waste's potential to cause human disease and injury. ATSDR has worked closely with other federal agencies to prepare a draft version of the report, using data obtained from the states and the private sector. The draft report has been peer reviewed for scientific merit and was made available in February 1990 to the public for review and comment; more than 1,800 copies of the draft report have been distributed.

[20 ELR 10282]

ATSDR's Future Directions

SARA added new mandates to ATSDR's health responsibilities under CERCLA. These included health assessments of sites and facilities proposed or placed on the NPL, development of a listing of priority hazardous substances, development of toxicological profiles on priority substances, initiation of substance-specific research, implementation of programs for health and medical education on hazardous substances, and preparation of a childhood lead poisoning report to Congress. To address these added responsibilities, ATSDR increased its staff, changed its structural organization, and developed new materials and resources.

ATSDR's principal focus is to determine the degree of morbidity and mortality associated with releases of hazardous substances from Superfund sites or facilities or from emergency releases of toxicants into the environment. These environmental public health concerns are based on risk assessments that draw heavily on the results of toxicological testing of laboratory animals, findings from occupational health investigations, and findings from some community environmental studies of human health. What is known is that there are persons who have come into contact with hazardous substances released from waste sites or through emergency releases. What is not known is the magnitude and severity of possible chronic adverse health effects. ATSDR's overall program is geared to providing answers to this question.

A comprehensive scientific literature on the human health effects of long-term exposure to environmental contaminants at the low concentrations usually found in communities is also lacking. Conducting such investigations is extremely difficult. Indeed, valid methods to measure human exposure or to assess presumptive exposure are often lacking. Moreover, human health outcome databases and environmental databases are still being developed by state and federal agencies. Although ATSDR has no answer to the central question of the extent of adverse health effects in human populations from chronic exposure to low concentrations of hazardous substances released from Superfund sites and facilities, the Agency is developing the necessary scientific tools, databases, and administrative resources to address that question. This means establishing select health data surveillance systems and registries, conducting health studies of target human populations (as identified from ATSDR's health assessments), developing or honing exposure assessment methods, improving medical testing procedures, and improving how we select diseases or illnesses for research. This plan will necessarily require the long-term commitment of people and funds.

1. Pub. L. No. 99-499, 100 Stat. 1613 (1986).

2. See Johnson, Health Effects of Hazardous Waste: The Expanding Functions of the Agency for Toxic Substances and Disease Registry, 18 ELR 10132 (Apr. 1988).

3. Siegel, Integrating Public Health Into Superfund: What Has Been the Impact of the Agency for Toxic Substances and Disease Registry?, 20 ELR 10013 (Jan. 1990).

4. Pub. L. No. 96-510, 94 Stat. 2767. CERCLA and SARA are codified together at 42 U.S.C. §§ 9601-675, ELR STAT. CERCLA 001-075.

5. RCRA § 11009, 42 U.S.C. § 6992h, ELR STAT. RCRA 050.

6. ATSDR, Health Assessments and Health Effects Studies of Hazardous Substances Releases and Facilities; Final Rule, 55 Fed. Reg. 5136 (1990) (to be codified at 42 C.F.R. § 90).

7. CERCLA § 104(i)(6)(B), 42 U.S.C. § 9604(i)(6), ELR STAT. CERCLA 019.

8. ATSDR, Policies and Procedures for Establishing a National Registry of Persons Exposed to Hazardous Substances, DHHS (1988).

9. ATSDR, Hazardous Substances Priority List, Toxicological Profiles; Notice, 53 Fed. Reg. 41280 (1988); see also ATSDR, The Third List of Hazardous Substances That Will be the Subject of Toxicological Profiles, 54 Fed. Reg. 43615 (1989).

10. ATSDR, Decision Guide for Identifying Substance-Specific Data Needs Related to Toxicological Profiles; Notice, 54 Fed. Reg. 37618 (1989).

11. CERCLA § 104(i)(14), 42 U.S.C. § 9604(i)(14), ELR STAT. CERCLA 021.

12. ATSDR, The Nature and Extent of Lead Poisoning in Children in the United States: A Report to Congress, DHHS (1988).

13. Pub. L. No. 100-582, § 2(a), 102 Stat. 2950, 42 U.S.C. § 6992.