Perchlorate: A System to Track Sampling and Cleanup Results Is Needed
Published: 2005-05-20T00:00:00

Fast Facts:

Highlights:
section_title: Why GAO Did This Study
paragraphs: Perchlorate, a primary ingredient in propellant, has been used for decades in the manufacture and firing of rockets and missiles. Other uses include fireworks, flares, and explosives. Perchlorate has been found in drinking water, groundwater, surface water, and soil in the United States. The National Academy of Sciences (NAS) reviewed studies of perchlorate's health effects and reported in January 2005 that certain levels of exposure may not adversely affect healthy adults but recommended more studies be conducted on the effects of perchlorate exposure in children and pregnant women. GAO determined (1) the estimated extent of perchlorate in the United States, (2) what actions have been taken to address perchlorate, and (3) what studies of perchlorate's health risks have reported.
section_title: What GAO Found
paragraphs: Perchlorate contamination has been found in water and soil at almost 400 sites in the United States where concentration levels ranged from a minimum reporting level of 4 parts per billion to millions of parts per billion. More than one-half of all sites were in California and Texas, and sites in Arkansas, California, Texas, Nevada, and Utah had some of the highest concentration levels. Yet, most sites had lower levels of contamination; roughly two-thirds of sites had concentration levels at or below the Environmental Protection Agency's (EPA) provisional cleanup standard of 18 parts per billion. Federal and state agencies are not required to routinely report perchlorate findings to EPA, and EPA does not centrally track or monitor perchlorate detections or the status of cleanup. As a result, a greater number of contaminated sites than we reported may already exist. Although there is no specific federal requirement to clean up perchlorate, EPA and state agencies have used broad authorities under various environmental laws and regulations, as well as state laws and action levels, to sample and clean up and/or require the sampling and cleanup of perchlorate by responsible parties. Further, under certain federal and state environmental laws, private industry may be required to sample for contaminants, such as perchlorate. According to EPA and state officials, private industry and public water suppliers have generally complied with regulations requiring sampling and agency requests to sample. The Department of Defense (DOD) has sampled and cleaned up perchlorate in some locations when required by laws and regulations, but the department has been reluctant to sample on or near active installations under other circumstances. Except where there is a specific legal requirement, DOD's perchlorate sampling policy requires the services to sample only under certain conditions. Cleanup is planned or under way at 51 of the almost 400 perchlorate-contaminated sites identified to date. Since 1998, EPA and DOD have sponsored a number of perchlorate health risk studies using varying study methodologies. We reviewed 90 of these studies that generally examined whether and how perchlorate affected the thyroid. About one-quarter concluded that perchlorate had an adverse effect. In January 2005, NAS reported on the potential health effects of perchlorate and concluded that a total exposure level from all sources, higher than that initially recommended by EPA (a dose equivalent to 1 part per billion in drinking water, assuming that all exposure came from drinking water) may not adversely affect a healthy adult. On the basis of NAS' report, EPA revised its reference dose to a level that is equivalent to 24.5 parts per billion in drinking water (if it is assumed that all exposure comes only from drinking water). The reference dose is not a drinking water standard; it is a scientific estimate of the total daily exposure level from all sources that is not expected to cause adverse effects in humans, including the most sensitive populations.

section_title: Letter
paragraphs: Ammonium perchlorate (perchlorate) is a primary ingredient in solid  rocket propellant and has been used for decades by the Department of  Defense (DOD), the National Aeronautics and Space Administration  (NASA), and the defense industry in the manufacturing, testing, and firing  of rockets and missiles. Private industry has also used perchlorate to  manufacture products such as automobile airbags, fireworks, flares, and  commercial explosives. Perchlorate is a naturally occurring and  manufactured salt that is easily dissolved and transported in water and has  been found in groundwater, surface water, and soil across the country.  Perchlorate has also been found in drinking water and food products, such  as milk and lettuce. Recent health studies have shown that perchlorate can  affect the thyroid gland and may cause developmental delays.
Due to questions and ongoing debate about the risks of exposing children  and pregnant women to low levels of perchlorate, four federal agencies  asked the National Academy of Sciences (NAS) to review and comment on  recent studies of perchlorate and its health effects. In January 2005, NAS  concluded that existing studies did not support a clear link between  perchlorate exposure and adverse health effects. NAS recommended a  perchlorate reference dose—an estimated daily exposure level from all  sources that is not expected to cause adverse effects in humans, including  the most sensitive populations—of 0.0007 milligrams per kilogram of body  weight per day. The dose is equivalent to 2 liters of drinking water per day  containing 24.5 parts per billion of perchlorate when consumed by an adult  weighing 70 kilograms (or 154 pounds), assuming that all perchlorate  exposure comes from drinking water. In February 2005, the Environmental  Protection Agency (EPA) adopted NAS’ recommended reference dose for  perchlorate, but it has not established a national federal standard for  perchlorate in drinking water or other regulatory requirements to clean up  perchlorate in groundwater, surface water, or soil.
In this context, we identified (1) the estimated extent of perchlorate found  in the United States; (2) what actions the federal government, state  governments, and responsible parties have taken to clean up or eliminate  the source of perchlorate; and (3) what studies of the potential health risks  from perchlorate have been conducted and, where presented, the author’s  conclusions or findings on the health effects of perchlorate.
To provide an estimate of the extent of perchlorate found in the United  States, we compiled and analyzed data on perchlorate detections from  EPA, DOD, the U.S. Geological Survey, and state agencies. To identify the  actions governments and responsible parties have taken to clean up and  eliminate the source of the perchlorate, we (1) reviewed federal and state  laws, regulations, and policies on water quality and environmental cleanup  and (2) interviewed EPA officials and selected state agency officials to  identify the authorities they have used to monitor and respond to instances  of perchlorate. We also interviewed EPA and state agency officials on  whether responsible parties have taken action to clean up perchlorate and  reviewed and analyzed data from federal and state agencies to determine  the status and extent of cleanup efforts. For the purposes of this report,  “cleanup” refers to ongoing efforts to remove perchlorate from water  and/or soil. However, our use of this term excludes pollution prevention  efforts, such as the removal of perchlorate from wastewater. To identify  studies of the potential health risks from perchlorate, who conducted them,  and what methodologies were used, we conducted a literature search for  studies of perchlorate health risks published since 1998, interviewed DOD  and EPA officials on what studies they considered important in assessing  perchlorate health risks, and examined the references of each study for  other studies we had not obtained. We identified 125 studies on perchlorate  and the thyroid, of which we reviewed 90 that were relevant to our review.  A more detailed description of our scope and methodology is presented in  appendix I. We conducted our work from June 2004 to March 2005 in  accordance with generally accepted government auditing standards,  including an assessment of data reliability and internal controls.
subsections: section_title: Background
paragraphs: Perchlorate is a primary ingredient in solid rocket propellant and has been  used for decades by DOD, NASA, and the defense industry in the  manufacturing, testing, and firing of rockets and missiles. On the basis of  1998 manufacturer data, EPA estimated that 90 percent of the perchlorate  produced in the United States is manufactured for use by the military and  NASA. Total typical production quantities average several million pounds  per year. Private industry has used perchlorate to manufacture products  such as fireworks, flares, automobile airbags, and commercial explosives.  Perchlorate is a salt, both manufactured and naturally occurring, and is  easily dissolved and transported in water. It has been found in drinking  water, groundwater, surface water, and soil across the country. There is no  national primary drinking water regulation for perchlorate. In 1992 and  again in 1995, EPA established a provisional reference dose range for  perchlorate of 0.0001 to 0.0005 milligrams per kilogram of body weight per  day. This converts to a drinking water concentration of between 4 and 18  parts per billion. On the basis of the drinking water conversion, EPA  identified a corresponding provisional cleanup level for perchlorate of  between 4 and 18 parts per billion.
subsections: section_title: History of Perchlorate Investigation and Study
paragraphs: Perchlorate was initially identified as a contaminant of concern by EPA in  1985, when it was found in wells at hazardous waste sites in California.  Perchlorate became a chemical of regulatory concern in 1997 after  California found perchlorate in the groundwater near Aerojet, a rocket  manufacturer in Rancho Cordova. At the time, perchlorate could not  reliably be detected below 400 parts per billion in water. In April 1997, a  new analytical method capable of detecting perchlorate in drinking water  at concentrations of 4 parts per billion became available. This development  prompted several states to test drinking water, as well as groundwater and  surface water, for perchlorate. Within 2 years, perchlorate had been  detected in drinking water in 3 western states and groundwater and surface  water in 11 states across the United States. Perchlorate in drinking water is  considered a more immediate concern.
In light of emerging concerns about perchlorate, EPA published in 1998 its  first draft risk assessment on the environmental risks of perchlorate  exposure. In February 1999, an external panel of independent scientists  reviewed EPA’s draft risk assessment and recommended additional studies  and analyses to provide more data on perchlorate and its health effects.  DOD and industry researchers conducted laboratory and field studies of  the health effects of perchlorate and submitted them to EPA. On the basis  of an analysis of these studies, EPA revised its draft perchlorate risk  assessment and released it for peer review and public comment in January  2002. The revised draft risk assessment included a proposed reference dose  equivalent to a concentration of 1 part per billion in drinking water, if it is  assumed all exposure comes only from drinking water. After a second  panel peer review, and some disagreement about the proposed reference  dose, EPA, DOD, NASA, and the Department of Energy asked NAS, in 2003,  to review EPA’s perchlorate risk assessment and key studies of the health  effects of perchlorate. These and other recent health studies have shown  that the consumption of perchlorate affects the human thyroid by  decreasing the amount of iodine absorbed. Iodine deficiency can result in  developmental delays if it occurs during pregnancy and early infancy and  can result in hypothyroidism if it occurs during adulthood. The purpose of  the NAS study was, in part, to assess the extent to which studies have  shown negative health effects from perchlorate.
In January 2005, NAS reported that existing studies did not support a clear  link between perchlorate exposure and developmental effects, and NAS  recommended additional research on perchlorate exposure and its effect  on children and pregnant women. NAS also recommended a safe exposure  level, or reference dose, for perchlorate of 0.0007 milligrams per kilogram  of body weight per day. (For comparison, EPA’s draft reference dose for  perchlorate in its 2002 draft risk assessment, which equated to a drinking  water concentration of 1 part per billion, was based on a daily dose of  0.00003 milligrams per kilogram of body weight per day.) According to  NAS, the reference dose is conservative and includes safeguards to protect  the most sensitive population, the fetus of the nearly iodine-deficient  pregnant woman. In February 2005, EPA established a new reference dose  for perchlorate on the basis of the NAS recommendation. The new  reference dose is equivalent to 24.5 parts per billion in drinking water,  assuming that an adult weighing 70 kilograms (or 154 pounds) consumes 2  liters of drinking water per day, and that all perchlorate ingested comes  from drinking water. If EPA establishes a drinking water standard for  perchlorate, however, it may be less than 24.5 parts per billion because  humans may consume perchlorate from other sources, such as produce  and milk.
In addition to studies of perchlorate and health effects, other federal  agencies, research groups, and universities have conducted or are  conducting studies of perchlorate found in food and the environment. For  example, the U.S. Geological Survey collected soil samples from California  and New Mexico to test for the presence of perchlorate in natural minerals  and materials. In 2003, an environmental research group reported that it  sampled lettuce purchased in northern California and found perchlorate  above 30 parts per billion in 4 of 22 samples. In September 2003,  researchers from Texas Tech University sampled 8 bottles of milk and 1 can  of evaporated milk and found perchlorate concentrations up to 6 parts per  billion in seven of the milk samples and more than 1 part per billion in the  evaporated milk sample. In 2004, the Food and Drug Administration  sampled the following items for perchlorate: lettuce, bottled water, milk,  tomatoes, carrots, cantaloupe, and spinach. Produce samples were taken  from areas where officials said they believed irrigation water contained  perchlorate. These data are currently being evaluated, but preliminary  results show perchlorate was found in some samples.
Method 314.0 is the EPA-approved method for analyzing perchlorate in  drinking water under the Safe Drinking Water Act. Method 314.0 can detect  perchlorate concentrations of 1 part per billion in finished (treated)  drinking water but has a minimum reporting limit of 4 parts per billion.  Both EPA and DOD officials have expressed concerns about using Method  314.0 to test for perchlorate in media other than drinking water, such as  groundwater, surface water, and soil (where researchers mix soil with a  liquid to extract the sample). According to EPA, sediment and dissolved  ions commonly found in groundwater and surface water can yield false  positive results if the method is not used properly. Analysis methods other  than Method 314.0 are available, and EPA has approved their use to analyze  specific sites for perchlorate. Further, two new methods have been  developed for the analysis of perchlorate in drinking water, and another is  expected to be available in the spring of 2005. These three methods have  minimum reporting limits ranging from 0.02 to 0.1 parts per billion.  However, Method 314.0 has been the principal method used to test and  report on the presence of perchlorate in all media, including soil, sediment,  groundwater, and surface water.
Various treatment technologies to remove perchlorate from groundwater  and surface water are in use or under review. Biological treatment and ion  exchange systems are among the technologies currently in use. Biological  treatment uses microbes to destroy perchlorate by converting the  perchlorate ion to nontoxic ions, oxygen, and chloride. Ion exchange  systems replace the perchlorate ion with chloride, which is an ion found in  table salt.
section_title: Environmental Laws, Regulations, and Federal Policy Covering Hazardous Substances
paragraphs: Several federal environmental laws provide EPA, and states authorized by  EPA, with broad authorities to respond to actual or threatened releases of  substances that may endanger public health or the environment. For  example, the Comprehensive Environmental Response, Compensation, and  Liability Act of 1980 (CERCLA), as amended, authorizes EPA to investigate  the release of any hazardous substance, pollutant, or contaminant. The  Resource Conservation and Recovery Act of 1976 (RCRA) gives EPA  authority to order a cleanup of hazardous waste when there is an imminent  and substantial endangerment to public health or the environment, and one  federal court has ruled that perchlorate is a hazardous waste under RCRA.  The Clean Water Act’s National Pollutant Discharge Elimination System  (NPDES) provisions authorize EPA, which may, in turn, authorize states, to  regulate the discharge of pollutants into waters of the United States. These  pollutants may include contaminants such as perchlorate. The Safe  Drinking Water Act authorizes EPA to respond to actual or threatened  releases of contaminants into public water systems or underground  sources of drinking water, regardless of whether the contaminant is  regulated or unregulated, where there is an imminent and substantial  endangerment to health and the appropriate state and local governments  have not taken appropriate actions. Under certain environmental laws such  as RCRA, EPA can authorize states to implement the requirements as long  as the state programs are at least equivalent to the federal program and  provide for adequate enforcement. A detailed summary of these and other  laws and regulations is presented in appendix IV.
In addition, some states have their own environmental and water quality  laws that provide state and local agencies with the authority to monitor,  sample, and require cleanup of various hazardous substances, both  regulated and unregulated, that pose an imminent and substantial danger to  public health. For example, the California Water Code authorizes Regional  Water Control Boards to require sampling of waste discharges and to direct  cleanup and abatement, if necessary, of any threat to water, which may  include the release of a contaminant such as perchlorate.
DOD’s September 2003 interim policy on perchlorate sampling states that  the military services shall sample for perchlorate where service officials  suspect the presence of perchlorate on the basis of prior or current DOD  activities, and where a complete human exposure pathway is likely to exist.  The policy also states that the services shall sample for perchlorate (1) as  required by the Safe Drinking Water Act’s Unregulated Contaminant  Monitoring Regulation and the Clean Water Act’s NPDES program and (2)  as part of cleanup conducted under DOD’s Environmental Restoration  Program. While DOD’s policy requires it to sample where the two  conditions of release and exposure are met, it does not specify whether the  services may sample for perchlorate when requested by state agencies or  EPA, apart from requirements under environmental laws and regulations.  Further, except for at a few sites,DOD has not independently directed the  services to clean up perchlorate. We previously reported that DOD has  cleaned up perchlorate when directed to do so by EPA or a state  environmental agency under various environmental laws, or when  perchlorate is found on closed ranges.
section_title: Perchlorate Has Been Found at Almost 400 Sites across the United States
paragraphs: Various federal and state agencies have reported finding perchlorate at  almost 400 sites in 35 states, the District of Columbia, and 2  commonwealths of the United States in drinking water, surface water,  groundwater, and soil. Perchlorate was found at a variety of sites including  public water systems, private wells, military installations, commercial  manufacturers, and residential areas. The concentration levels reported  ranged from 4 parts per billion to more than 3.7 million parts per billion in  groundwater at 1 site, yet roughly two-thirds of sites had concentration  levels at or below 18 parts per billion, the upper limit of EPA’s provisional  cleanup guidance for perchlorate. Federal and state agencies are not  required to routinely report perchlorate findings to EPA, and EPA does not  currently have a formal process to centrally track or monitor perchlorate  detections or the status of a cleanup. As a result, a greater number of sites  may exist in the United States than is presented in this report.
subsections: section_title: The Majority of Perchlorate Was Found in California and Texas
paragraphs: Through discussions with federal and state environmental agency officials  and a review of perchlorate sampling reports, we identified 395 sites in the  United States and its commonwealths where perchlorate was found in  drinking water, groundwater, surface water, sediment, or soil. A table of  reported perchlorate detections in the United States and its  commonwealths as of January 2005 is presented in appendix II.
Most of the sites and the highest levels of perchlorate were found in a small  number of states. More than one-half of all sites, or 224, was found in Texas  and California, where both states have conducted broad investigations to  determine the extent of perchlorate. The highest perchlorate  concentrations were found in 5 states—Arkansas, California, Nevada,  Texas, and Utah—where 11 sites had concentrations exceeding 500,000  parts per billion. However, the majority of the 395 sites had lower levels of  perchlorate. We found 249 sites where the highest concentration was equal  to or less than 18 parts per billion, the upper limit of EPA’s provisional  cleanup level, and 271 sites where the highest concentration was less than  24.5 parts per billion, the drinking water concentration equivalent  calculated on the basis of EPA’s newly established reference dose (see fig.  1).
According to EPA and state agency officials, perchlorate found at 110 of the  sites was due to activities related to defense and aerospace, such as  propellant manufacturing, rocket motor research and test firing, or  explosives disposal. At 58 sites, officials said the source of the perchlorate  found was manufacturing and handling, agriculture, and a variety of  commercial activities such as fireworks and flare manufacturing (see fig.  2).
At the remaining 227 sites, EPA and state agency officials said the source of  the perchlorate found was either undetermined or naturally occurring.  Further, all 105 sites with naturally occurring perchlorate are located in the  Texas high plains region where perchlorate concentrations range from 4 to  59 parts per billion.
section_title: Perchlorate Was Found in 4 As of January 2005, and as required for a 12-month period between 2001 Percent of Sampled Public Drinking Water Systems
paragraphs: and 2003 under the Safe Drinking Water Act’s Unregulated Contaminant  Monitoring Regulation, 3,722 public drinking water systems had sampled  drinking water and reported the results to EPA. Of these public drinking  water systems, 153, or about 4 percent, reported finding perchlorate.  Located across 26 states and 2 commonwealths, these 153 sites accounted  for more than one-third of the sites we identified, where perchlorate  concentrations reported ranged from 4 parts per billion to 420 parts per  billion and averaged less than 10 parts per billion. Only 14 of the 153 public  drinking water systems had concentration levels above 24.5 parts per  billion, the drinking water equivalent calculated on the basis of EPA’s  revised perchlorate reference dose. California had the most public water  systems with perchlorate, where 58 systems reported finding perchlorate in  drinking water. The highest drinking water perchlorate concentration of  420 parts per billion was found in Puerto Rico in 2002. Subsequent  sampling in Puerto Rico did not find any perchlorate, and officials said the  source of the initial finding was undetermined.
Because of the proximity of these 153 public water systems to populated  areas, an EPA official estimated that about 10 million people may have  been exposed to perchlorate through their drinking water. EPA officials  told us that they do not know the source of most of the perchlorate found  in public water systems, but that perchlorate found in 32 water systems in  Arizona, California, and Nevada was likely due to previous perchlorate  manufacturing in Nevada. Regional EPA and state officials told us they did  not plan to clean up perchlorate found at public drinking water sites  pending a decision to establish a drinking water standard for perchlorate.  In some cases, officials did not plan to clean up because subsequent  sampling was unable to confirm that perchlorate was present.
section_title: Extent of Perchlorate and Cleanup Efforts Is Difficult to Determine Because Federal and State Agencies Are Not Generally Required to Share with EPA Information on Perchlorate Sampling or Cleanup
paragraphs: EPA officials said the agency does not centrally track or monitor  perchlorate detections, or the status of cleanup activities, other than under  the Safe Drinking Water Act where EPA collected data from public water  systems for 1 year. As a result, it is difficult to determine the extent of  perchlorate in the United States. EPA maintains a listing of sites known to  EPA where cleanup or other response actions are under way, but the list  does not include all sites because some sites have not been reported to  EPA. As a result, EPA officials said they did not always know whether other  federal and state agencies found perchlorate because, as is generally the  case with unregulated contaminants, there is no requirement for states or  other federal agencies to routinely report perchlorate findings to EPA. For  example, except as required under specific environmental programs, DOD  is not required to report to EPA when perchlorate is found on active  installations and facilities. Consequently, EPA region officials in California  said they did not know that the Department of the Navy found perchlorate  at the Naval Air Weapons Station at China Lake. Further, even where EPA  has authorized states to implement the RCRA program, states are not  required to routinely notify EPA about perchlorate found under the  program. For example, EPA region officials in California said the Nevada  state agency did not tell them perchlorate was found at Rocketdyne, an  aerospace facility in Reno, or that it was being cleaned up. EPA only  learned about the perchlorate finding when the facility’s RCRA permit was  renewed.
We also found that communication and data sharing between EPA and state  agency officials varied. Because states are not required to routinely notify  EPA about perchlorate, some EPA region officials told us they contacted  state agencies to ask whether new sites had been found. Some EPA region  and state officials told us they participated in monthly or quarterly  meetings to discuss perchlorate, and most EPA and state officials told us  they had good working relationships and shared information about  perchlorate. Yet a few EPA region officials told us they did not always  know whether states found perchlorate, at what levels, or what actions  were taken. For example, an EPA region official told us he did not know  what actions were taken at three RCRA sites in Utah where perchlorate  was found.
section_title: EPA and State Environmental Agencies Use Federal and State Environmental Laws and Regulations to Respond to Perchlorate
paragraphs: Although there is no federal standard for perchlorate in drinking water or a  federal cleanup standard, EPA and state environmental agencies  authorized by EPA have investigated suspected sites; collected samples  and analyzed for perchlorate; and, when perchlorate is found, cleaned up  or limited perchlorate releases under broad authorities found in various  federal environmental laws and regulations. Further, both EPA and  authorized states have required responsible parties to sample and clean up  perchlorate under other state laws. Most responsible parties sampled and  cleaned up when required by regulation or directed by EPA or states. DOD  sampled and cleaned up on the basis of its interpretation of federal and  state legal requirements and its own policy. Of the 395 sites where  perchlorate has been found, EPA or state environmental officials told us  cleanup is under way or planned at 51 of them.
subsections: section_title: Various Environmental Laws, Regulations, and Provisional Standards Are Used by Federal and Some State Agencies to Sample and Clean Up Perchlorate
paragraphs: We found EPA and state environmental agencies have investigated,  sampled, and cleaned up perchlorate, or have required sampling and  cleanup, pursuant to general authorities contained in various federal and  state environmental laws and regulations. According to EPA and state  agency officials, state agencies have also established levels for sampling  and cleanup, and some state environmental laws provide that other  authorities are to respond to contaminant releases, including perchlorate.
Both EPA and state environmental agencies have used federal  environmental laws, such as CERCLA, RCRA, and the NPDES provisions of  the Clean Water Act, as authority to respond to releases of substances that  may endanger public health or the environment, including perchlorate. EPA  and the states have used such authority to sample and clean up as well as  require the sampling and cleanup of perchlorate. For example:
As part of a CERCLA review, EPA sampled groundwater near former  government-owned grain storage facilities in Iowa and found  perchlorate in residential and commercial drinking water wells at three  sites. During subsequent sampling, EPA did not find perchlorate at two  of the sites but confirmed perchlorate at the third site. EPA is providing  bottled drinking water to certain persons until an uncontaminated  drinking water supply becomes available.
During sampling required as part of a RCRA permit, ATK Thiokol, a Utah  explosives and rocket fuel manufacturer, found perchlorate. Under  authority provided by RCRA, Utah required the manufacturer to install a  monitoring well to determine the extent of perchlorate and take steps to  prevent additional perchlorate releases.
Under the NPDES program, Texas required the Navy to reduce  perchlorate levels in wastewater discharges at the McGregor Naval  Weapons Industrial Reserve Plant to 4 parts per billion, the lowest level  at which perchlorate could be detected.
According to EPA and state officials, EPA and state environmental agencies  have investigated and sampled groundwater and surface water areas for  perchlorate, or requested that responsible parties or others do so, pursuant  to agency oversight responsibilities to protect water quality and human  health. For example:
EPA plans to sample five waste disposal sites in Niagara Falls, New  York, to determine whether the groundwater contains perchlorate from  manufacturing that took place in the area between 1908 and 1975.
EPA asked Patrick Air Force Base and the Cape Canaveral Air Force  Station, Florida, to sample groundwater for perchlorate near rocket  launch sites. Previously, both installations inventoried areas where  perchlorate was suspected and conducted limited sampling. DOD  officials did not find perchlorate at Patrick Air Force Base, and,  according to an EPA official, the Department of the Air Force said it  would not conduct additional sampling at either installation until there  is a federal standard for perchlorate.
Between 1998 and 2002, Utah sampled public drinking water systems  considered at risk for the presence of perchlorate because of nearby  perchlorate use and found perchlorate concentrations at more than 42  parts per billion in three wells at two sites.
Texas contracted with Texas Tech University to sample drinking water  wells for perchlorate in 54 counties after perchlorate was found in five  public water systems in the high plains region of the state. The  university study found perchlorate in some drinking water wells and  concluded that the most likely source was natural occurrence.
When perchlorate was found, according to state and EPA officials, state  agencies have taken steps to minimize human exposure or perform  cleanup, or required responsible parties to do so, pursuant to the same  general authorities contained in federal environmental laws and  regulations. For example:
Nevada is requiring Pepcon, a former perchlorate manufacturing site, to  install a cleanup system to remove perchlorate from groundwater.
Massachusetts closed a public well and provided bottled drinking water  to students at a nearby school when perchlorate was found in a city  public water system.
At the request of California, United Technologies, a large rocket testing  facility in Santa Clara County, stopped releasing perchlorate and  cleaned up perchlorate found in the groundwater.
Without a federal standard for perchlorate, according to EPA and state  officials, at least nine states have established nonregulatory action levels or  advisories for perchlorate ranging from under 1 part per billion to 18 parts  per billion. States that have sampled, or required responsible parties to  sample, report, and clean up, have used these advisories as the levels at  which action must be taken. For example:
Oregon initiates in-depth site studies to determine the cause and extent  of perchlorate when concentrations of 18 parts per billion or greater are  found.
Nevada required the Kerr-McGee Chemical site in Henderson to treat  groundwater and reduce perchlorate concentration releases to 18 parts  per billion, which is Nevada’s action level for perchlorate.
According to Utah officials, Utah does not have a written action level for  perchlorate, but, if perchlorate concentrations exceed 18 parts per  billion, the state may require the responsible party to clean up.
Finally, in addition to state laws enacted to allow states to assume  responsibility for enforcing federal environmental laws, other state  environmental laws provide authority to respond to contaminant releases,  including perchlorate. For example, EPA and state officials told us that  both California and Nevada state agencies have required cleanup at some  sites under state water quality laws.
section_title: Parties Responsible for Perchlorate Findings Generally Have Complied with Regulations Requiring Sampling and Cleanup
paragraphs: According to EPA and state officials, private industry and public water  suppliers have generally complied with regulations requiring sampling,  such as those under (1) the RCRA and NPDES permit programs, where  responsible parties have been required to sample and report hazardous  releases to state environmental agencies, or (2) the Safe Drinking Water  Act’s Unregulated Contaminant Monitoring Regulation, which required  sampling for unregulated contaminants, such as perchlorate, between 2001  and 2003. Further, according to EPA and state officials, private industry has  generally responded by reducing perchlorate and cleaning up when  required by regulation or directed by EPA or state agencies.
section_title: DOD’s Policy Requires Sampling for Perchlorate under Certain Conditions
paragraphs: DOD’s perchlorate sampling policy requires the military services to sample  where the particular installation must do so, under laws or regulations such  as the Clean Water Act’s NPDES permit program, or where a reasonable  basis exists to suspect that a perchlorate release has occurred as a result of  DOD activities and that a complete human exposure pathway is likely to  exist. However, DOD’s policy on perchlorate sampling does not address  cleanup. We found DOD has sampled for perchlorate on closed  installations when requested by EPA or a state agency and cleaned up on  active and closed installations when required by a specific environmental  law, regulation, or program, such as the environmental restoration program  at formerly used defense sites. For example, at EPA’s request, the U.S.  Army Corps of Engineers (Corps) installed monitoring wells and is  sampling for perchlorate at Camp Bonneville, a closed installation near  Vancouver, Washington. Utah state officials told us DOD is removing soil  containing perchlorate at the former Wendover Air Force Base in Utah,  where the Corps found perchlorate in 2004.
According to EPA and state officials, DOD has been reluctant to (1) sample  on or near active installations because there is no specific federal  regulatory standard for perchlorate or (2) sample where DOD determined  the criteria to sample were not met as outlined in its policy. Except where  there is a legal requirement to sample at a particular installation, DOD’s  perchlorate policy does not require sampling unless the two conditions of  release and exposure are met. Utah state officials told us the agency asked  the Department of the Army to sample for perchlorate at two active  installations, Dugway Proving Grounds and Deseret Chemical Depot.  Previously, in 1998, the Army reported that perchlorate had been used at  Dugway for more than 20 years. According to state agency officials, the  Army said there was not a clear potential for human exposure to  perchlorate at these sites, and it would not sample unless a higher Army  level approved the sampling. In February 2005, Utah officials told us  Dugway Proving Grounds had not requested permission from Army  headquarters to sample, and they did not know whether Deseret requested  permission to sample.
In fiscal years 2004 and 2005, several provisions to federal law were  enacted that encourage DOD to conduct health studies and evaluate  perchlorate found at military sites. For example, the Ronald W. Reagan  National Defense Authorization Act for Fiscal Year 2005 states that the  Secretary of Defense should develop a plan for cleaning up perchlorate  resulting from DOD activities, when the perchlorate poses a health hazard,  and continue evaluating identified sites. In October 2004, DOD and  California agreed to a procedure for prioritizing perchlorate sampling at  DOD facilities in California. The procedure includes steps to identify and  prioritize the investigation of areas on active installations and military sites  (1) where the presence of perchlorate is likely based on previous and  current defense-related activities and (2) near drinking water sources  where perchlorate was found. Although DOD has been urged by Congress  to evaluate sites where the presence of perchlorate is suspected, DOD’s  September 2003 perchlorate policy continues to require sampling on active  installations only where there is a suspected release due to DOD activities  and a likely human exposure pathway, or where required under specific  laws, such as the Clean Water Act.
section_title: EPA and States Are Cleaning Up, Requiring Cleanup, or Taking Action to Clean Up 51 Sites Where Perchlorate Was Found
paragraphs: EPA, state agencies, and responsible parties are cleaning or planning to  clean up at 51 of the 395 sites we identified. At 23 sites, EPA, states, and  responsible parties are cleaning up or working to reduce perchlorate  releases. For example, EPA required several defense, petroleum, and other  companies to clean up perchlorate in Baldwin Park, California, a CERCLA  site. The cleanup involves extracting and treating up to 26 million gallons of  water per day, after which the water is distributed to several nearby  communities. Texas required Longhorn Army Ammunition Plant, a closed  DOD facility, to clean up by limiting perchlorate releases to a daily average  concentration of 4 parts per billion (and a maximum of 13 parts per billion  per day) under the NPDES program. Kerr-McGee Chemical, a former  perchlorate manufacturer in Nevada, is cleaning up using an ion exchange  system. According to officials, Nevada required the facility to clean up  perchlorate under a state water law after perchlorate concentrations up to  3.7 million parts per billion were found in the groundwater.
At 28 sites, EPA and state agency officials told us that federal and state  governments and private parties are evaluating the extent of perchlorate  and potential cleanup methodologies. Unidynamics, an Arizona propellant  manufacturer located at a CERCLA site, responded to EPA’s concern about  perchlorate at the site and is investigating perchlorate treatment methods.  According to officials, after Kansas asked Slurry Explosives to clean up  perchlorate under a state environmental law, the manufacturer began  investigating a biological method to clean up.
The remaining 344 sites are not being cleaned up for a variety of reasons.  The reason most often cited by EPA and state officials was that they were  waiting for a federal requirement to do so. In some instances, officials said  they would not clean up sites where perchlorate was naturally occurring or  where subsequent sampling was unable to find perchlorate.
section_title: DOD and EPA Sponsored Numerous Studies of Perchlorate Exposure, but Findings about Perchlorate’s Health Effects Are Inconsistent
paragraphs: Since 1998, EPA and DOD have sponsored a number of studies of the health  risks of perchlorate using experimental, field study, and data analysis  methods. We reviewed 90 of these studies and found that 44 offered  conclusions or observations on whether perchlorate had a health effect. Of  these, 26 studies found that perchlorate had an adverse effect. However, in  some of these studies, it was unknown whether the observed adverse  effects would be reversible over time. In January 2005, NAS issued its  report on EPA’s draft health assessment and the potential health effects of  perchlorate. The NAS report considered many of the same health risk  studies that we reviewed and concluded that an exposure level higher than  initially recommended by EPA may not adversely affect a healthy adult, but  recommended more study of the effects of perchlorate on pregnant women  and children.
subsections: section_title: Study Findings Differed on the Health Effects of Perchlorate Exposure
paragraphs: DOD, industry, and EPA sponsored the majority of the 90 health studies we  reviewed; the remaining studies were conducted by academic researchers  and other federal agencies. Of these 90 studies, 49 used an experimental  design methodology to determine the effects of perchlorate on humans,  mammals, fish, and/or amphibians by exposing these groups to differing  dose amounts of perchlorate over varied periods of time and comparing the  results with other groups that were not exposed. Twelve were field studies  that compared humans, mammals, fish, and/or amphibians in areas known  to be contaminated with the same groups in areas known to be  uncontaminated. Both methodologies have limitations; that is, the  experimental studies were generally short in duration, and the field studies  were generally limited by the researchers’ inability to control whether, how  much, or how long the population in the contaminated areas was exposed.  Finally, 29 studies used a data analysis methodology where researchers  reviewed several publicly available human and animal studies and used  data derived from these studies to determine the process by which  perchlorate affects the human thyroid and the highest exposure levels that  did not adversely affect humans. The 3 remaining studies used another or  unknown methodology. Appendix III provides data on these studies,  including who sponsored them; what methodologies were used; and, where  presented, the author’s conclusions or findings on the effects of  perchlorate.
Many of the studies we reviewed contained only research findings, not  conclusions or observations, on the health effects of perchlorate. Only 44  studies had conclusions on whether perchlorate had an adverse effect. Of  these, 29 studies evaluated the effect of perchlorate on development, and  18 found adverse effects resulting from maternal exposure to perchlorate.  Adverse effects of perchlorate on the adult thyroid are difficult to evaluate  because they may happen over longer time periods than can be observed in  a research study. However, the adverse effects of perchlorate on  development can be more easily studied and measured within study time  frames. Moreover, we found different studies used the same perchlorate  dose amount but observed different effects. The different effects were  attributed to variables such as the study design type or age of the subjects,  but the precise cause of the difference is unresolved. Such unresolved  questions are one of the bases for the differing conclusions in EPA, DOD,  and academic studies on perchlorate dose amounts and effects. According  to EPA officials, the most sensitive population for perchlorate exposure is  the fetus of a pregnant woman who is also nearly iodine-deficient.  However, none of the 90 studies we reviewed considered this population.  Some studies reviewed pregnant rat populations and the effect on the  thyroid, but we did not find any studies that considered perchlorate’s effect  on nearly iodine-deficient pregnant populations and the thyroid.
section_title: The National Academy of Sciences Reported That Evidence Was Insufficient to Show Perchlorate Causes Adverse Effects
paragraphs: In January 2005, NAS issued its report on EPA’s draft health assessment and  the potential health effects of perchlorate. NAS reported that although  perchlorate affects thyroid functioning, there was not enough evidence to  show that perchlorate causes adverse effects at the levels found in most  environmental samples. Most of the studies NAS reviewed were field  studies, the report said, which are limited because they cannot control  whether, how much, or how long a population in a contaminated area is  exposed. NAS concluded that the studies did not support a clear link  between perchlorate exposure and changes in the thyroid function in  newborns and hypothyroidism or thyroid cancer in adults. In its report,  NAS noted that only 1 study examined the relationship between  perchlorate exposure and adverse effects on children, and that no studies  investigated the relationship between perchlorate exposure and adverse  effects on vulnerable groups, such as low-birth-weight infants. NAS  concluded that an exposure level higher than initially recommended by  EPA may not adversely affect a healthy adult. The report did not  recommend a drinking water standard; however, it did recommend that  additional research be conducted on perchlorate exposure and its effect on  children and pregnant women.
section_title: Conclusions
paragraphs: Perchlorate has been found in the groundwater, surface water, drinking  water, or soil in 35 states, the District of Columbia, and 2 commonwealths  of the United States where concentrations reported ranged from 4 parts per  billion to millions of parts per billion. According to EPA and state  environmental agency officials, a leading known cause of the perchlorate  found was defense-related activities. In addition, EPA and state officials  attributed the cause of the perchlorate found at more than one-half of sites  to natural occurrence or undetermined sources. State and other federal  agencies do not always report perchlorate detections to EPA, however,  because EPA, other federal agencies, and the states do not have a  standardized approach for reporting perchlorate data nationwide. As a  result, a greater number of sites with perchlorate may already exist.  Further, EPA does not track the status of cleanup at sites where  perchlorate has been found. Without a formal system to track and monitor  perchlorate findings and cleanup activities, EPA and the states do not have  the most current and complete accounting of perchlorate as an emerging  contaminant of concern, including the extent of perchlorate found and the  extent or effectiveness of cleanup projects.
section_title: Recommendation for Executive Action
paragraphs: In order to ensure that EPA has reliable information on perchlorate and the  status of cleanup efforts, and to better coordinate lessons learned between  federal agencies and states on investigating and cleaning up perchlorate,  we recommend that, in coordination with states and other federal agencies,  EPA use existing authorities or seek additional authority, if necessary, to  establish a formal structure to centrally track and monitor perchlorate  detections and the status of cleanup efforts across the federal government  and state agencies.
section_title: Agency Comments and Our Evaluation
paragraphs: In its April 26, 2005, letter (see app. V), EPA agreed with our findings and  conclusions on the extent of perchlorate in the United States and that  defense-related activities have been found to be associated with  perchlorate detections. However, EPA did not agree with our  recommendation that it establish a formal structure to centrally track and  monitor perchlorate detections and the status of cleanup efforts across the  federal government and state agencies. In its letter, EPA stated that it  already had significant information and data on perchlorate concentrations  in various environmental media, where much of the information was  provided by other federal and state agencies as well as private parties. EPA  also asserted that the development and maintenance of a new tracking  system would require additional resources or the redirection of resources  from other activities. To justify a tracking system, EPA would have to  analyze its associated costs and benefits.
As our report explains, however, state and other federal agencies do not  always report perchlorate detections to EPA. Further, without a formal  system to track and monitor perchlorate findings and cleanup activities,  EPA does not have the most current and complete accounting of  perchlorate as an emerging contaminant of concern. To underscore our  point, in commenting on a draft of this report, DOD provided a listing of  four sites where it found perchlorate between 2000 and 2004. These sites  were not in EPA’s database. (We added these sites to our listing in app. II.)  With regard to the cost benefit aspect of EPA’s comments, we believe that  EPA is misconstruing the extent of work necessary to implement a more  formalized and structured system to track perchlorate. We are not  proposing an elaborate new system but, instead, believe that EPA needs to  work toward a more structured process than what is currently in place to  track and monitor perchlorate routinely. Currently, EPA’s regions are  spending time and effort contacting their counterparts in other federal  agencies and states on an ad hoc basis to obtain more current information  about perchlorate. However, this is being done without any structure or  consistency related to how and when contacts are made, how frequently  they are made, or what specific information is collected. As a result, we  found that EPA does not have complete, current, or accurate information to  track the occurrence of perchlorate—the type of information that would be  needed when making a determination about the need for regulation. We  continue to believe that such information is necessary and that it can be  obtained without an elaborate or costly undertaking.
In contrast to EPA’s view of our report’s accuracy, DOD said in its April 26,  2005, letter (see app. VI), that our report did not provide an accurate  assessment of perchlorate issues and activities. DOD asserted that our  report mischaracterized DOD’s response to perchlorate and cited examples  of where DOD has sampled and invested in cleanup technologies, even  though perchlorate is currently unregulated. We disagree with DOD’s  position. Our report credits DOD with actions it has taken but also points  out where DOD has not acted. For example, our report acknowledges that  DOD is sampling for perchlorate as required under various environmental  laws, or when certain criteria exist as specified in DOD’s sampling policy;  that is, where the presence of perchlorate is suspected based on prior or  current DOD activities and a complete exposure pathway to humans is  likely to exist. While DOD states that it has a policy that establishes an  affirmative obligation to sample and not a limitation, that view is not  shared by some regulators. As we point out in our report, there have been a  number of instances where EPA or state agencies asked the services to  sample but service officials declined because they did not believe the  conditions met with DOD’s sampling policy. As such, DOD has used its  policy to limit testing for perchlorate that environmental regulators  believed was necessary.
With regard to DOD’s point that perchlorate is unregulated, we are well  aware that many other contaminants, like perchlorate, are not specifically  regulated, yet are being addressed and cleaned up as hazards under various  environmental laws.
DOD also stated that we did not accurately summarize the findings of the  NAS study and other scientific and technical data. We believe our report  accurately summarizes key information from both NAS as well as 90 other  studies of the potential health risks of perchlorate, as specified by the  requester of this report.
Finally, DOD disagreed with our recommendation that EPA establish a  more formal structure to centrally track and monitor perchlorate because it  was not clear that such a system will provide added value. DOD stated that  it will continue to share its information on perchlorate. As previously  noted, in commenting on this report, DOD provided information on four  locations where perchlorate has been found, in one case as long as 5 years  ago, and which do not appear on EPA’s list of perchlorate detection sites.  Whether this omission occurred as a result of a DOD or an EPA oversight is  unknown, but it underscores the need for a more structured and formalized  system.
Both EPA and DOD provided technical comments as enclosures to their  letters, which we incorporated in our report as appropriate.
As agreed with your office, unless you publicly announce the contents of  this report earlier, we plan no further distribution until 30 days from the  report date. At that time, we will send copies of this report to the  appropriate congressional committees; the Administrator, Environmental  Protection Agency; the Secretary of Defense; and other interested parties.  We will also provide copies to others upon request. In addition, the report  will be available, at no charge, on the GAO Web site at http://www.gao.gov.
If you or your staff have any questions, please call me or Edward Zadjura at  (202) 512-3841. Contributors to this report are listed in appendix VII.
section_title: Objectives, Scope, and Methodology
paragraphs: We identified (1) the estimated extent of perchlorate nationwide; (2) what  actions the federal government, state governments, and responsible parties  have taken to clean up or eliminate the source of perchlorate found; and  (3) what studies of the potential health risks from perchlorate have been  conducted and, where presented, the author’s conclusions or findings on  the health effects of perchlorate.
To provide an estimate of the extent of perchlorate in the United States, we  compiled and analyzed data on perchlorate detections from the  Environmental Protection Agency (EPA), the Department of Defense  (DOD), the U.S. Geological Survey, and state agencies. For each site, our  review shows the highest perchlorate concentration reported for all media  sampled as of January 2005, although officials may have sampled the site  more than once, in varying locations and media, and found differing levels  of perchlorate. We also interviewed officials from EPA headquarters and  regional offices, DOD, and selected state agencies to determine the  accuracy and completeness of our compiled list of perchlorate detections.
To identify what actions the government and private sector have taken to  address perchlorate and the extent to which responsible parties have taken  action to clean up and eliminate the source of perchlorate, we reviewed  federal and state laws, regulations, and policies on water quality and  environmental cleanup and interviewed EPA and state agency officials on  their roles, responsibilities, and authorities to monitor and respond to  instances of perchlorate found. We interviewed officials from EPA  headquarters and each of its 10 regions. We also interviewed officials from  state environmental agencies in California, Oregon, Texas, and Utah. We  selected these states because they (1) had higher estimated numbers of  sites where perchlorate was found and higher perchlorate concentration  levels and/or (2) had taken steps to investigate and respond to perchlorate.  During interviews with state agency officials, we discussed whether parties  responsible for perchlorate had taken action to clean up and whether  federal or local governments required that they stop activities causing the  release of perchlorate. Finally, we reviewed and analyzed data from federal  and state agencies to determine the status and extent of cleanup efforts.
To identify studies of the potential health risks from perchlorate, we  conducted a literature search for studies of perchlorate health risks  published since 1998. We also interviewed DOD and EPA officials to obtain  a list of the studies they considered important in assessing perchlorate  health risks. We examined the references for each study so that we could  include any other key studies that we had not obtained through the  literature search and DOD and EPA interviews. We identified 125 studies of  perchlorate and the thyroid but did not review 35 of these studies because  they were not directly related to the effects of perchlorate on the thyroid.  Our review of 90 studies included the title; the author and publication  information; the sponsor or recipient; a description of the study subjects;  the type of research design and controls; and, where presented, the  author’s conclusions or findings about the adverse effects of perchlorate on  health.
We conducted our work from June 2004 to March 2005 in accordance with  generally accepted government auditing standards, including an  assessment of data reliability and internal controls.
section_title: Facilities and Sites Where Perchlorate Was Found and Concentration Levels, as of January 2005
paragraphs: Anniston Army Depot, Calhoun County  Atmore Utility Board, Escambia County  Daphne Utilities Board, Baldwin County  Fort McClellan, City of Anniston  Mobile County Water and Fire Protection  Authority, Mobile County  Montgomery Water Works, Montgomery  County  Redstone Army Arsenal (NASA Marshall  Space Flight Center)
Amount (ppb)
Amount (ppb)
Amount (ppb)
Royal Palm Beach Utilities, Palm Beach  County  Sebring Water and Sewer System, Highlands  County  Three Worlds Camp Resort, Polk County  City of Watkinsville, Oconee County  Feagin Mill, Houston County  Iowa Army Ammunition Plant, Middletown  Chanute Air Force Base, Rantoul  City of Joliet, Will and Kendall Counties  City of Rock Island, Rock Island County  Sangamo Electric Dump/Crab Orchard  National Wildlife Refuge, City of Carterville  (Department of the Interior)
Amount (ppb)
City of Hagerstown, Washington County  Fort George Meade, City of Odenton  Naval Surface Warfare Center, Indian Head  White Oak Federal Research Center (Naval  Surface Warfare Center)
City of Deming, Luna County  Fort Wingate Depot, Gallup  Holloman Air Force Base, Alamogordo  Kirtland Air Force Base, Albuquerque  Los Alamos National Laboratory, City of Los  Alamos (Department of Energy)
Melrose Air Force Bombing Range, City of  Clovis  Mountain View Albuquerque, City of South  Valley  New Mexico American Water Company, City  of Clovis  Sandia National Labs, City of Albuquerque  (Department of Energy)
Amount (ppb)
Amount (ppb)
Amount (ppb)
Maple Water Service Company, Bailey County  McClain private well, Midland County  McGregor Naval Weapons Industrial Reserve  Plant, McLennan County  McMurries private well, Martin County  Minnix private well, Midland County  Mobile Home Park, Lubbock County  Nelms private well, Midland County  Nobels private well, Midland County  North State Highway 115, Winkler County  North University Estates, Lubbock County  North West Yoakum, Yoakum County  O'Brien private well, Dawson County  Offield private well, Midland County  Pantex Plant, City of Amarillo, Carson County  (Department of Energy)
Amount (ppb)
Purdue Farms, Incorporated, Accomack  County  Camp Bonneville, City of Vancouver  City of Puyallup, Pierce County  Firgrove Mutual, Incorporated, Pierce County  Lacey Water Department, Thurston County  Lakewood Water District, Pierce County  Allegheny Ballistics Lab, City of Rocket Center  Parts per billion (ppb).
section_title: Perchlorate Health Risk Studies Published Since 1998
paragraphs: Author’s  findings/  conclusions  about the  adverse effects  of perchlorate  on health  New diagnostic  Not identified/  criteria (see Unknown.  original study  for experimental  controls)
Established  incidence  probabilities  (see original  study for  experimental  controls)
Adverse effects  indicated.
New diagnostic  Adverse effects  criteria for indicated.  reviewing data  (see original  study for  experimental  controls)
Revised Analysis  Crofton  of the Thyroid  Hormone Data  from the Mouse  Immunotoxicology  Study (from Keil et  al., 1999)
Nonadverse  effects indicated.  No information  available on  adverse effects.
Nonadverse  effects indicated.  Adverse effects to  development  indicated.
Keil, et al.
Dose, duration,  Nonadverse  age, sex, and  weight  (dose levels  independently  verified) effects indicated.  Information on  adverse effects is  incomplete.
Keil, et al.
Dose, duration,  Nonadverse  age, sex, strain,  effects indicated.  and weight No adverse  (dose levels effects indicated.  independently  verified)
ManTech  Environmental  Technology,  Inc.
Dose, duration,  Nonadverse and  sex, and weight  adverse effects  indicated.
ManTech  Environmental  Technology,  Inc.
Nonadverse  effects and  adverse  developmental  effects indicated.
Author’s  findings/  conclusions  about the  adverse effects  of perchlorate  on health  Nonadverse  effects and  adverse  developmental  effects indicated.
Bekkedal, et  Department of  Animal  al. Defense  developmental  effects indicated.
Adverse effects to  development  indicated.
Protection  Agency/  Original study:  Perchlorate  Study Group  development  indicated.
Dose, duration,  Adverse effects to  and age  development  indicated.
Adverse effects to  development  indicated.
Adverse effects to  development  indicated.
Effects not  studied.
Dose, duration,  Adverse effects to  and sex  development  indicated.
No adverse  developmental  effects indicated.
Nonadverse and  adverse effects  indicated.
Nonadverse and  adverse effects  indicated.
Nonadverse  effects indicated.  No information  available on  adverse effects.
Nonadverse  effects indicated.  No information  available on  adverse effects.
Nonadverse  effects indicated.  No information  adverse effects.
Analysis of Dose- Marcus  Response  Functions for  Effects of  Perchlorate on  Serum Hormone  from Data of Greer  et al. (2000, 2002)  and Merrill (2001a)
Nonadverse  effects indicated.  No information  available on  adverse effects.
Nonadverse  effects indicated.  Potential adverse  developmental  effects indicated.
Anion Selectivity by  Van Sande,  Ministere de  Cells  the Sodium Iodide  et al.  Symporter  la Politique  Scientifique,  and Fonds  effects indicated.  No information  available on  adverse effects.
Not identified/  Not identified/  Review/  Unknown Unknown  effects indicated.  No information  available on  adverse effects.
Effects not  studied.
Nonadverse  effects indicated.  No information  available on  adverse  developmental  effects.
Effects not  studied (model  developed).
Effects not  studied (model  developed).
Effects not  studied.
Effects not  studied (model  developed).
Effects not  studied (model  developed).
Carr, et al.
Nonadverse  effects indicated.  No adverse  developmental  effects indicated.
Carr, et al.
Adverse  developmental  effects indicated.
Carr, et al.
Adverse  developmental  effects indicated.
Carr, et al.
Adverse  developmental  effects indicated.
Effects not  studied  (reference dose  developed).
Sharma, et  Perchlorate  al.
Dose, repeated  No adverse  study, bacteria  strain, and sex  effects indicated.
Dose, duration,  Nonadverse  and switched  exposed/control  No information  litters with  exposed/  control dams  effects indicated.  available on  adverse  developmental  effects.
Dose, duration,  Nonadverse  and switched  exposed/  control litters  with exposed/  control dams  effects indicated.  No information  available on  adverse  developmental  effects.
Not identified/  Unknown.
Nonadverse and  adverse effects  indicated.
Findings not  used--design  limitations too  great.
No adverse  effects indicated.
Tsui, et al.
Effects not  studied.
No nonadverse or  adverse effects  indicated.
Author’s  findings/  conclusions  about the  adverse effects  of perchlorate  on health  Nonadverse  effects indicated.  No information  available on  adverse  developmental  effects.
Nonadverse  effects indicated.  No information  available on  adverse  developmental  effects.
No adverse  effects indicated.
York, et al.
Nonadverse  effects indicated.  Adverse effects to  development  indicated.
Author’s  findings/  conclusions  about the  adverse effects  of perchlorate  on health  Adverse effects  indicated.
Clewell, et  al.
Nonadverse  effects indicated.  No information  available on  adverse effects.
Duration, dose,  Nonadverse and  and recovery adverse effects  period indicated.
York, et al.
Nonadverse  effects indicated.  Adverse  developmental  effects indicated.
York, et al.
Nonadverse  effects indicated.  No adverse  developmental  effects indicated.
York, et al.
Nonadverse  effects indicated.  No adverse  developmental  effects indicated.
No adverse  developmental  effects indicated.
No adverse  effects indicated.
Effects not  studied.
Nonadverse  effects indicated.  No adverse  effects indicated.
Not identified/  No effects  Unknown  indicated.
Baseline tests  Nonadverse  performed to  ensure subjects  No information  had no prior available of  thyroid adverse effects.  problems  effects indicated.
Not identified/  Unknown.
Clewell, et  al.
Dose, duration,  Effects not  and model  controls  studied (model  developed).
Clewell, et  al.
Dose, duration,  Effects not  and model  controls  studied (model  developed).
Dose, duration,  Effects not  and model  controls  studied (model  developed).
Dose, duration,  Effects not  and model  controls  studied (model  developed).
Yu, et al.
Dose, duration,  Nonadverse  and model  controls  effects indicated.  No information  available on  adverse effects.
Effects not  studied  (reference dose  developed).
In Vitro Mammalian  San and  Cell Gene Mutation  Clarke  Test (L5178Y/TK  Mouse Lymphoma  Assay)
No adverse effect  indicated.
Adverse effect on  development  indicated.
Consultative Letter:  Channel  Kinetic Data for  Iodide Uptake  Inhibition in the  Thyroid by  Perchlorate (2- Week Drinking  Water Study)
No effects  indicated.
Effects not  studied (model  developed).
Nonadverese  effects indicated.  Adverse effects to  development  indicated.
Effects not  studied  (bechmark dose  developed).
Incidence rates,  No adverse  age, sex,  race/ethnicity,  population size,  and  demographic  features  effects indicated.
Effects not  studied.
Adverse effects to  development  indicated.
Dose and  breeding pairs  (analysis with  paired groups  and individual  pups)
Nonadverse  effects indicated.  Adverse effects to  development  indicated.
Iodide Transport in  Harrison, et  Howard  Xenopus Laevis al.
Effects not  studied.
Nonadverse  effects indicated.  No information  available on  adverse  developmental  effects.
section_title: Summary of Certain Environmental Laws and Regulations
subsections: section_title: The Resource Conservation and Recovery Act
paragraphs: The Resource Conservation and Recovery Act (RCRA) was enacted as an  amendment to the Solid Waste Disposal Act to create a framework for the  management of hazardous and nonhazardous solid waste. It authorizes  EPA to control hazardous waste from the point where waste is generated  through its transportation, treatment, storage, and disposal. EPA  regulations define hazardous waste to include waste specifically listed in  the regulation as well as those defined as “characteristic waste.”  Characteristic hazardous waste is defined as waste that is ignitable,  corrosive, reactive, or toxic. A federal district court in California ruled, in  part, that perchlorate is a hazardous waste under RCRA because it is  ignitable, under certain conditions.
RCRA requires owners and operators of facilities that treat, store, and  dispose of hazardous waste, including federal agencies, to obtain permits  specifying how they will safely manage waste. Under RCRA’s corrective  action provisions, facilities seeking or holding RCRA permits can be  required to clean up their hazardous waste contamination. Under RCRA,  EPA has the authority to order a cleanup of hazardous waste when there is  an imminent and substantial endangerment to public health or the  environment. EPA may authorize states to administer their own programs  in lieu of the federal program, as long as these programs are equivalent to  and consistent with the federal program and provide for adequate  enforcement. Under RCRA, state agencies have required RCRA permit  holders to sample for and report on perchlorate detections and prevent  additional releases.
section_title: Comprehensive Environmental Response, Compensation, and Liability Act
paragraphs: The Comprehensive Environmental Response, Compensation, and Liability  Act (CERCLA), commonly known as Superfund, governs the cleanup of  releases or threatened releases of hazardous substances, pollutants, or  contaminants. CERCLA’s definition of a hazardous substance includes  substances regulated under various other environmental laws, including  RCRA, the Clean Air Act, the Clean Water Act, and the Toxic Substances  Control Act. Under section 120 of CERCLA, the federal government is  subject to and must comply with CERCLA’s requirements to the same  extent as any nongovernmental entity. CERCLA provides broad authority to  EPA to respond to releases or threatened releases of hazardous substances  or pollutants or contaminants that may endanger public health or the  environment. Under these provisions, DOD has responded to perchlorate  found on military installations and facilities. CERCLA establishes  prohibitions and requirements for contaminated sites; provides for the  liability for hazardous substances at these sites; and provides for the use of  the Hazardous Substances Superfund, a trust fund to provide for cleanup,  for example, when a responsible party cannot be identified. The law  authorizes short-term removal—where actions may be taken to address  releases or threatened releases requiring prompt response—and long-term  response—where actions may be taken to permanently reduce the danger  associated with a release. EPA identifies the most hazardous sites, those  requiring long-term action, by listing them on the National Priorities List.
section_title: The Clean Water Act
paragraphs: The Clean Water Act authorizes EPA to regulate the discharge of pollutants  into waters of the United States. EPA may authorize states to carry out a  state program in lieu of the federal program if the state program meets the  requirements of the Clean Water Act, including providing for adequate  enforcement. The act defines a pollutant to include virtually all waste  material. The act provides for the establishment of national discharge  limitations, water quality standards, and a permit program and has  provisions for addressing oil and toxic substance spills. Covered private  parties as well as federal facilities must comply with the requirements of  the act. According to EPA, since pollutants are defined broadly in the act to  include most waste material, perchlorate would likely fall within this  definition.
Under the Clean Water Act’s National Pollution Discharge Elimination  System (NPDES) program, facilities discharging pollutants into waters of  the United States from point sources are required to obtain an NPDES  permit from EPA or authorized states. NPDES permits include specific  limits on the quantity of pollutants that may be discharged and require  monitoring of those discharges to ensure compliance. Industrial,  municipal, and other facilities must obtain permits to discharge specific  pollutants if their discharges go directly to waters of the United States.  Sites with NPDES permits are required to routinely sample and report to  state regulatory agencies on the release of specified pollutants, which may  include contaminants such as perchlorate.
section_title: The Federal Facility Compliance Act
paragraphs: Under section 107 of the Federal Facility Compliance Act of 1992, EPA was  required, in consultation with DOD and the states, to issue a rule  identifying when military munitions become hazardous waste under RCRA  and to provide for protective storage and transportation of that waste.  Under the rule issued by EPA, used or fired military munitions become  waste subject to RCRA regulation if, among other things, (1) they are  transported off-range for waste management purposes or (2) they or their  constituents are recovered, collected, and then disposed of by burial on or  off a range. Unexploded, used, and fired military munitions are known  sources of perchlorate. Under RCRA, as amended by the Federal Facility  Compliance Act, EPA maintains that DOD installations may be required to  sample and monitor off-range for perchlorate as well as other contaminants  associated with military munitions where EPA has evidence that the  contaminants are creating an imminent and substantial endangerment to  health or the environment.
section_title: The Safe Drinking Water Act
paragraphs: The Safe Drinking Water Act authorizes EPA to issue national primary  drinking water regulations setting maximum contaminant-level goals and  maximum contaminant levels for drinking water that must be met by public  water systems. EPA may authorize states to carry out primary  enforcement authority for implementing the Safe Drinking Water Act if,  among other things, the states adopt drinking water regulations that are no  less stringent than the national primary drinking water regulations. EPA  has set standards for approximately 90 contaminants in drinking water;  however, most of the more than 200 chemical contaminants associated  with munitions use, including perchlorate, are currently unregulated under  the Safe Drinking Water Act.
The 1996 amendments to the Safe Drinking Water Act required EPA to (1)  establish criteria for a monitoring program for unregulated contaminants,  where a maximum contamination level has not been established, and (2)  publish a list of contaminants chosen from those not currently monitored  by public water systems. EPA’s regulation, referred to as the Unregulated  Contaminant Monitoring Regulation, was issued in 1999 and supplemented  in 2000 and 2001. The purpose of the regulation was to determine whether  a contaminant occurs at a frequency and in concentrations that warrant  further analysis and research on its potential effects, and to possibly  establish future drinking water regulations. The first step in the most  recent program required public water systems serving more than 10,000  customers—and a sample of 800 small public water systems serving 10,000  or fewer customers—to monitor drinking water for perchlorate and 11  other unregulated contaminants over a consecutive 12-month period during  2001 and 2003 and to report the results to EPA. According to EPA, large  public water systems provide drinking water to about 80 percent of the U.S.  population served by public water systems.
section_title: Comments from the Environmental Protection Agency
section_title: Comments from the Department of Defense
section_title: GAO Contacts and Staff Acknowledgments
subsections: section_title: GAO Contacts
section_title: Staff Acknowledgments
paragraphs: In addition to the individuals named above, John Delicath, Christine Frye,  Alan Kasdan, Karen Keegan, Roderick Moore, Edith Ngwa, James Rose, and Rebecca Shea made key contributions to this report.