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History of Perchlorate Health Effects Research: 50 Years of Deception and Delay

CDC Scientists Find Rocket Fuel Chemical In Infant Formula: History of Perchlorate Health Effects Research: 50 Years of Deception and Delay

April 2, 2009


By Renée Sharp, Senior Analyst
Anila Jacob, M.D., Senior Analyst

1940's: Large-scale production of perchlorate begins, expanding along with the growth of the postwar military-industrial complex.

1952: Perchlorate is found to impair normal thyroid function by interfering with iodine uptake by the thyroid gland (1).

1957: Study shows that perchlorate can pass through the placenta and can affect fetal animals more seriously than adults (2).

1957: Article in the Journal of the American Water Works Association describes how "several California municipalities have experienced pollution of ground water supplies as a result of local underground disposal practices [of rocket fuel waste]" (3).

1950's - 60's: Perchlorate's inhibitory effects on thyroid hormone production are exploited by physicians to treat hyperthyroidism/Grave's disease (overactive thyroid) (4).

1960's: Reports of adverse effects of perchlorate treatment for Grave's disease begin to appear in the medical literature (5,6,7).

1962: Industry and the Department of Defense form the Inter-Agency Chemical Rocket Propulsion Group with the goal of making sure that perchlorate rules and regulations do not impose "unnecessary and excessive restrictions to industrial operations" (8).

1964: California Department of Water Resources tests groundwater in Sacramento and finds perchlorate in 34 wells at levels of up to 18,000 ppb (9).

1966: Study published showing that eleven of 76 severely ill Graves' disease patients treated with perchlorate suffered at least moderate and sometimes fatal hematological side effects (10).

Late 1960's: Physicians move on to safer and more effective treatments for hyperthyroidism (4).

1979 - 1985: Perchlorate found at Superfund sites in California (11, 12).

1992: EPA issues first provisional safe dose for perchlorate, equivalent to 4 ppb in drinking water (11).

1992: Industry launches the front group, the Perchlorate Study Group funded by Aerojet, Alliant Techsystems, American Pacific/Western Electrochemical Company, Atlantic Research Corporation, Kerr-McGee Chemical Corporation, Lockheed Martin, Thiokol Propulsion Group, and United Technologies Chemical Systems (13).

1995: EPA's provisional safe dose raised to range equivalent of 4 ppb to 18 ppb, after industry-funded studies are submitted to EPA (11,14).

1995: EPA finds that laboratory animals developed thyroid disorders after two weeks of drinking perchlorate-laced water (15).

1997: California Department of Health Services discovers perchlorate contamination in the Colorado River while trying to develop new detection method; contamination is traced hundreds of miles upstream to a Department of Defense contractor manufacturing perchlorate. Subsequent testing finds widespread contamination in California groundwater (15).

1997: California sets action level for perchlorate in drinking water of 18 ppb (16).

1998: EPA raises provisional range to 32 ppb, even after a new study shows that perchlorate can cause health effects at lower doses than expected and has greater effects when consumed for longer periods of time (17).

1999: External peer review of EPA's "safe" dose concludes that more research is needed before an official EPA level could be set (18).

1999: EPA lists perchlorate under the federal Unregulated Contaminant Monitoring Rule, with monitoring beginning in January of 2001 (19).

2000: Arizona state health department finds a significant increase in abnormal thyroid hormone levels in infants whose mothers drank perchlorate-tainted water from the Colorado River while pregnant (20).

2000: US News & World Report reveals that defense contractor Lockheed Martin and the Air Force are paying "volunteers" $1,000 to swallow doses of perchlorate in a study at Loma Linda University in Southern California, in an attempt to prove the contaminant is not harmful.

2001: EWG research finds that sources of drinking water for more than 7 million Californians and unknown millions of other Americans are contaminated with perchlorate, and recommends a drinking water standard of 4 parts per billion (ppb).

2002: EPA issues a revised "safe" dose of perchlorate, equivalent to 4 ppb, based on animal studies showing effects at very low levels. California revises its action level to 4 ppb (16).

2002: Greer et al publish findings after studying effects of varying doses of perchlorate on 37 health volunteers; according to study authors, the statistical no observed level (NOEL) is 0.007 mg/kg/day (21).

2002: Beginning this year and every year since, DoD seeks a congressional exemption from all state and federal environmental laws for uses of chemical constituents in military munitions, including perchlorate.

2002: EWG uncovers secret Air Force tests that show leafy vegetables grown with contaminated irrigation water take up, store and concentrate potentially harmful levels of perchlorate.

2003: EWG research finds that 20 million Americans drink water contaminated with perchlorate, which has been detected in water or soil in 43 states. In light of studies showing health effects from minute doses, EWG lowers its recommended drinking water standard to 0.1 ppb.

2003: EWG's first-ever tests for perchlorate in supermarket produce find that winter lettuce from California, sold nationwide, may contain up to 4 times more of the chemical than EPA considers safe in drinking water.

2004: EWG finds perchlorate in 31 of 32 samples of milk from California supermarkets.

2004: FDA publishes study on perchlorate food contamination, finds extensive contamination of the nation's food supply (22).

2005: The National Research Council of the National Academies of Science publishes its technical review of perchlorate (Health Implications of Perchlorate Ingestion). EPA used information from the review to set reference dose (RfD) for perchlorate of 0.0007 mg/kg/day, equivalent to 24.5 ppb (23).

2005: Scientists from Texas Tech University test 36 breast milk samples from 18 states for perchlorate and find contamination in every sample (24).

2005: Government Accountability Office (GAO) report details perchlorate contamination of drinking water supplies in 28 states, at concentrations ranging from 4 ppb to over 420 ppb (25).

2006: EPA Superfund office issues guidance without public comment recommending a drinking water equivalent level (DWEL) of 24.5 ppb at hazardous waste sites (26).

2006: EPA's Children's Health Protection Advisory Committee (CHPAC) writes EPA administrator arguing Preliminary Remediation Goal (PRG) is not protective of infants (27).

2006: EPA responds that it is standing by the PRG (28).

2006: EPA's response to questions from the House Energy and Commerce Committee identify 61 DoD facilities contaminated with perchlorate. Thirty-five are listed on National Priority List (NPL). Twenty-nine of these sites had sampling results exceeding EPA's RfD of 24.5 ppb. Of the 26 non-NPL sites, 15 sites exceed EPA's proposed RfD (29).

2006: Massachusetts becomes the first state in the U.S. to set drinking water standard for perchlorate (2 pbb), based on animal and human studies (30). 2006: CDC scientists publish two studies using NHANES data, representing the first large epidemiological studies to investigate relationship between perchlorate exposure and thyroid hormone levels (31,32). Key findings include:

  • Perchlorate is found in the urine of every one of 2,820 U.S. residents (ages 6 and older) in a nationally representative sample.
  • Children ages 6 to 11 are exposed to an average of 1.6 times more perchlorate than adults.
  • Perchlorate exposure at levels significantly lower than the EPA RfD of 24.5 ppb are associated with a lowering of thyroid hormone levels in women who are iodine insufficient (one third of American women).

2007: Rebutting questions from Republican Congressmen Joe Barton and John Shimkus of the House Committee on Energy and Commerce challenging these findings, the CDC states bluntly "…the findings of the Blount (thyroid) study are consistent with causality." "We do not think that confirmatory analysis is necessary to validate Blount's analysis using the NHANES data" (33).

2007: Scientists from CDC and academia publish two studies confirming widespread contamination of breast milk with perchlorate (34, 35).

2007: California sets drinking water standard for perchlorate (6 ppb) based on human studies (36).

2008: FDA publishes study finding that three-quarters of nearly 300 commonly-consumed foods and beverages are contaminated with perchlorate (37).

2008: EPA isues an Interim Drinking Water Health Advisory for Perchlorate of 15 ppb based on the agency's RfD. A health advisory is "informal technical guidance" to federal, state and local officials, rather than a legally enforceable standard but nonetheless reflects the agency's current thinking on what a safe level would be in drinking water (38).


1) Stanbury, J.B. and J.B. Wyngaarden. 1952. Effect of perchlorate on the human thyroid gland. Metabolism 1:533-539

2) Postel, S. 1957. Placental transfer of perchlorate and triiodothyronine in the guinea pig. Endocrinology 60: 53-66.

3) Journal of the American Water Works Association. 1957. Underground waste disposal and control. 49(10): 1334-1342.

4) Wolff J. 1998. Perchlorate and the thyroid gland. Pharmacological Reviews. 50 (1); 89-105.

5) Southwell, N. and K. Randall. 1960. Potassium perchlorate in thyrotoxicosis. Lancet. March 19: 653-654.

6) Hobson, Q.J.G. 1961. Aplastic anemia due to treatment with potassium perchlorate. British Medical Journal. May 13: 1368-1369.

7) Johnson, R.S. and W.G. Moore. 1961. Fatal aplastic anemia after treatment of thyrotoxicosis with potassium perchlorate. British Medical Journal. May 13: 1369-1371.

8) Manufacturing Chemists Association. 1962. Report to Manufacturing Chemists' Association, Inc. board of directors, by Ralph Bloom, Jr. Chairman, technical subcommittee on chemical propellant safety. April 10, 1962. From, Chemical Industry Archives, CMA 068023. pdf 1276.

9) California Department of Water Resources. 1964. Folsom-East Sacramento ground water quality investigation. Bulletin no. 133.

10) Barzilai, D. and M, Sheinfeld. 1966. Fatal complications following use of potassium perchlorate thyrotoxicosis: report of two case studies and a review of the literature. Israel J. Med: 453-456.

11) Environmental Protection Agency. 1998. Perchlorate Environmental Contamination: Toxicological review and risk characterization based on emerging information. Washington D.C.

12) Interstate Technology & Regulatory Council. 2008. Remediation Technologies for Perchlorate Contamination in Water and Soil. March 2008. Available:

13) Environment California. 2006. The Politics of Rocket Fuel Pollution. Available:

14) Jarabek, A.M. 1998. Background and objectives of ongoing studies. Presented at the 1998 Perchlorate Stakeholders Forum in Henderson, Nevada.

15) Caldwell, D.J., J.H. King Jr., E.R. Kinkead, R.E. Wolfe, L. Narayanan, and D.R. Mattie. 1995. Results of a fourteen day oral-dosing toxicity study of ammonium perchlorate. In: Proceedings of the 1995 JANNAF safety and environmental protection subcommittee meeting: volume 1. December. Tampa, FL. Columbia, MD: Chemical Propulsion Information Agency. Joint Army, Navy, NASA, Air Force (JANNAF) interagency propulsion committee publication 634. As cited in EPA 1998.

16) California Office of Environmental Health Hazard Assessment. 2004. Frequently Asked Questions (FAQs) About the Public Health Goal for Perchlorate. Available:

17) Springborn Laboratories, Inc. 1998. A 90-day drinking water toxicity study in rats with ammonium perchlorate: amended final report. Spencerville, OH. Study no. 3455.1. As cited in EPA 1998.

18) Environmental Protection Agency. 2008. Contaminant Focus: Perchlorate: Toxicology. Available:

19) Environmental Protection Agency. 2008. Fact sheet: Unregulated Contaminant Monitoring Rule 1 (UCMR 1). Available:

20) Brechner, R.J., G.D. Parkhurst, W.O. Humble, M.B. Brown, and W.H. Herman. 2000. Ammonium perchlorate contamination of Colorado river drinking water is associated with abnormal thyroid function in newborns in Arizona. JOEM 42(8): 777-782.

21) Greer MA, Goodman G, Pleus RC, Greer SE. 2002. Health effects assessment for environmental perchlorate contamination: the dose-response for inhibition of thyroidal radioiodine uptake in humans. Environmental Health Perspectives 110: 927-37.

22) U.S. Food and Drug Administration. 2004-2005 Exploratory Survey Data on Perchlorate in Food. Available:

23) National Academy of Sciences. 2005. Health Implications of Perchlorate Ingestion. National Academies Press, Washington, D.C.

24) Kirk AB, Martinelango PK, Tian K, Dutta A, Smith EE, Dasgupta PK. 2005. Perchlorate and iodide in dairy and breast milk. Environmental Science and Technology 39(7) 2011-17.

25) GAO. 2005. Perchlorate: a system to track sampling and cleanup results is needed. Report to the Chairman, Subcommittee on Environment, and Hazardous Materials, Committee on Energy and Commerce, House of Representatives.

26) U.S. Environmental Protection Agency memo. 2006. Assessment guidance for perchlorate. Available:

27) U.S. Environmental Protection Agency Children's Health Protection Advisory Committee letter to EPA administrator. 2006. Available:

28) U.S. Environmental Protection Agency response. 2006. Available:

29) U.S. Environmental Protection Agency, Superfund Sites Where You Live. 2006. Available:

30) Massachusetts Department of Environmental Protection. 2006. Addressing Perchlorate and other emerging contaminants in Massachusetts. Available:

31) Blount BC, Valentin-Blasini L, Osterloh JD, Mauldin JP, Pirkle JL. 2006. Perchlorate exposure of the U.S. population, 2001-2002. Journal of Exposure Science and Environmental Epidemiology. Oct 18: epub ahead of print.

32) Blount BC, Pirkle JL, Oserloh JD, Valentin-Blasini L, Caldwell KL. 2006. Urinary Perchlorate and thyroid hormone levels in adolescent and adult men and women living in the Unites States. Environmental Health Perspectives 114(12): 1865-71.

33) Centers for Disease Control and Prevention's responses to questions for the record from House Committee on Energy and Commerce. 2007. Available:

34) 4) Kirk AB, Dyke JV, Martin CF, Dasgupta PK. 2007. Temporal patterns in Perchlorate, thiocyanate, and iodide excretion in human milk. Environmental Health Perspectives 115(2) 182-86.

35) Pearce EN, Leung AM, Blount BC, Bazrafshan HR, He X, Valentin-Blasini L, Braverman LE. Breast milk iodine and Perchlorate concentrations in lactating Boston area women. Journal of Clinical Endocrinology and Metabolism. Feb 20, 2007 epub ahead of print.

36) California Department of Public Health. 2008. Perchlorate in Drinking Water. Available:

37) Murray CW, Egan SK, Kim H, Beru N, Bolger PM. 2008. US Food and Drug Administration's Total Diet Study: Dietary intake of perchlorate and iodine. Journal of Exposure Science and Environmental Epidemiology, 1-10.

38) Interim Drinking Water Health Advisory for Perchlorate PDF. December 2008, EPA 822-R-08-25. Available: