Powdered Cow’s Milk Formula Contains Thyroid Toxin
CDC Scientists Find Rocket Fuel Chemical In Infant Formula
Powdered Cow’s Milk Formula Contains Thyroid Toxin
Researchers from the U.S. Centers for Disease Control and Prevention (CDC) have reported that 15 brands of powdered infant formula are contaminated with perchlorate, a rocket fuel component detected in drinking water in 28 states and territories.
The two most contaminated brands, made from cow’s milk, accounted for 87 percent of the U.S. powdered formula market in 2000, the scientists said.
The CDC scientists did not identify the formula brands they tested.
The little-noticed CDC findings, published in the March 2009 edition of the Journal of Exposure Science and Environmental Epidemiology, raise new concerns about perchlorate pollution, a legacy of Cold War rocket and missile tests. Studies have established that the chemical is a potent thyroid toxin that may interfere with fetal and infant brain development (Kirk 2006).
The CDC team warned that mixing perchlorate-tainted formula powder with tap water containing “even minimal amounts” of the chemical could boost the resulting mixture’s toxin content above the level the Environmental Protection Agency (EPA) considers safe. Many scientists contend that the EPA “safe” level is too high to protect public health.
“Safe” level too high
The risk to infants being fed cow's milk-based formula may be even greater than the CDC assessment suggests. A CDC study in 2006 found that trace perchlorate exposure considerably below the EPA’s “safe” level (0.7 micrograms of perchlorate per kilogram of body weight per day, called the reference dose, or RfD) altered women’s thyroid hormone levels (Blount et al 2006a).
Based on this study, the Environmental Working Group has recommended that EPA promptly set a legally enforceable upper limit on perchlorate contamination in drinking water, consistent with the latest science on perchlorate’s toxic effects.
Obama EPA considering action
At her January 14 confirmation hearing, EPA administrator Lisa Jackson promised California Senator Barbara Boxer, whose state has borne the brunt of perchlorate contamination from old launch sites and aerospace facilities, that she would act “immediately” to reduce perchlorate contamination in drinking water in order to protect children and pregnant women.
Since her confirmation, however, Jackson and EPA have not made public a plan of action.
Pentagon lobbied Bush administration
Last fall, the Bush administration’s EPA leadership touched off a major furor by declaring that perchlorate posed no threat to most Americans and did not need to be regulated as a drinking water pollutant.
The decision was widely regarded as a major victory for the Pentagon and defense and aerospace contractors reluctant to pay clean-up costs that could mount into the hundreds of millions of dollars.
EPA’s move triggered protests from consumers, lawmakers, scientists and medical experts - among them, two of the agency’s prestigious outside science advisory panels.
Melanie A. Marty, a senior career EPA official and chair of EPA’s Children's Health Protection Advisory Committee, declared that the agency’s refusal to regulate perchlorate in drinking water exposed some infants to "the life-long consequences of impaired brain development.”
On January 8, EPA issued a non-binding “health advisory” on perchlorate and asked the National Academy of Sciences to review the issue.
EWG dismissed EPA’s action as “nothing more than an effort to dodge the issue and buy time for the defense, aerospace and chemical industries.”
Years of federal inaction have prompted some states to set their own mandatory limits for perchlorate in drinking water: California, at 6 ppb and Massachusetts at 2 ppb. While recent scientific research has shown these standards too weak to protect public health adequately, they are far more stringent than EPA’s action in January.
Studies find pollution in people, food
Concern about perchlorate pollution has intensified as a series of studies have found perchlorate in the urine of every American tested by the CDC and in breast milk (Blount et al 2006b, Pearce et al 2007).
In 2008, an EWG analysis found that toddlers were especially vulnerable to perchlorate exposure from contaminated food. Toddlers, who are growing rapidly, consume large amounts of food daily, relative to their size. Moreover, those who live in places like California and Texas, where high perchlorate levels have been measured in some drinking water supplies, are doubly exposed to perchlorate contamination.
EWG’s analysis was based on 2008 federal Food and Drug Administration (FDA) tests that found almost 75 percent of food and beverage samples tainted with perchlorate, possibly from contaminated irrigation water (Murray et al 2008).
CDC finds perchlorate in 15 formula brands
The new CDC study is the first to examine perchlorate exposure of infants fed powdered formula reconstituted with contaminated drinking water. The CDC team tested 15 brands of powdered infant formula in four categories: cow milk-based with lactose, cow milk-based lactose-free, soy-based and elemental.
“Perchlorate was found in all brands and types of infant formula tested,” the scientists said. The worst perchlorate contamination was found in formula based on cow’s milk with lactose.
The CDC team said that combining cow’s milk/lactose formula with water containing perchlorate at just 4 parts per billion (ppb) could cause 54 percent of infants consuming the mix to exceed EPA’s “safe” level.
The number of babies exposed to unsafe levels of perchlorate would rise if, as EWG and many other science and health advocates argue, the EPA “safe” level were lowered to reflect recent scientific studies.
Formula required to contain iodine
While these findings are of concern, the CDC scientists also note that FDA requires infant formula to be supplemented with iodine, a nutrient that can counteract the negative effects of perchlorate on the thyroid gland. The range of required iodine concentrations in formula is between 5 and 75 micrograms per 100kcal of energy.
Iodine supplements at higher levels may offer some protection from the toxic effects of perchlorate. But the CDC scientists estimate that those brands that contain only the minimum iodine concentration of 5 micrograms would leave infants iodine-deficient and thus more vulnerable to the toxic effects of perchlorate. A scenario in which formula contained 40 micrograms of iodine (per 100kcal of energy) would offer more protection for infants, but the scientists stress that even adequate iodine intake among formula-fed infants is not guaranteed to prevent “perchlorate-induced thyroid dysfunction.”
Strict drinking water regulation of perchlorate needed
This study represents perhaps the strongest evidence to date supporting the need for a legally enforceable safe drinking water level that protects pregnant women, infants and others who are most vulnerable to the effects of this harmful chemical.
The new Obama administration leadership at EPA can and should take steps to reduce infants’ exposures to perchlorate pollution in tap water.
Blount BC, Pirkle JL, Oserloh JD, Valentin-Blasini L, Caldwell KL. 2006a. 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.
Blount BC, Valentin-Blasini L, Osterloh JD, Mauldin JP, Pirkle JL. 2006b. Perchlorate exposure of the US population, 2001-2002. Journal of Exposure Science and Environmental Epidemiology 17(4): 400-07.
Kirk AB. 2006. Environmental perchlorate: why it matters. Analytical Chimica Acta 567(1): 4-12.
Murray WM, Egan SR, 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 18(6): 571-80.
Pearce EN, Leung AM, Blount BC, Bazrafshan HR, He X, Pino S, Valentin-Blasini L, Braverman LE. 2007. Breast milk iodine and perchlorate concentrations in lactating Boston area women. Journal of Clinical Endocrinology and Metabolism 92: 1673-77.
History of Perchlorate Health Effects Research: 50 Years of Deception and Delay
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).
Take Action to Remove Rocket Fuel Chemicals from your Infant Formula
Tell EPA to make the drinking water you use for your infant formula safer by removing the rocket fuel chemical (perchlorate) in your water.
If you live in CA, your drinking water safety limit is not stringent enough.
The CDC does not name the 15 brands of powdered infant formula found to contain perchlorate (rocket fuel chemical) contamination.
Call your infant formula company and ask a spokesperson about perchlorate contamination in the company’s product.
We'd also like you to report back to us what the company says.
Here are a few questions you can ask:
1. Is my brand of formula contaminated with perchlorate?
2. If so, how much perchlorate does my product contain?
3. Did you know about the product’s contamination with perchlorate before the new CDC report?
4. What plans do you have to clean up the formula? When?
Phone Numbers for Major Infant Formula Manufacturers
Nestlé Nutrition: 800.422-ASK2 (2752)
Nature's One: 888. 227.7122
PBM Products: 800.959.2066
The Hain Celestial Group: 800.434.4246
Frequently Asked Questions
1. How can I tell if my formula is contaminated with perchlorate?
The CDC scientists did not identify the formula brands they tested. But we do know that their research only included powdered infant formula. If you are feeding your baby powdered formula, we recommend that you contact your manufacturer to determine its full contents. You'll find a list of manufacturers and their phone numbers on our Take Action page, along with a form where you can let us know what they said.
2. I live in a state with perchlorate contaminated drinking water; how can I remove it from my drinking water?
Even if you live in a state in which perchlorate has been found, your specific municipal water supply may not be contaminated. We recommend that you call your water company and ask them if they have tested for perchlorate. If they have, and perchlorate has been found in your tap water, we recommend water filtration. At this point, a reverse osmosis filter that specifically removes perchlorate is your best option. FDA testing of bottled water found contamination in 2 of 51 samples so bottled water may not be safe either; in addition, EWG testing of 10 major bottled water brands found 38 pollutants.
3. How does the EPA explain its failure to regulate perchlorate?
EPA relies heavily on outdated research to justify its decision not to regulate perchlorate. In the last three years, the CDC has published two landmark studies that provide strong evidence that EPA should regulate perchlorate. In the first study, the CDC researchers found perchlorate in the urine of almost 3,000 Americans tested, indicating widespread exposure among the U.S. population. In the second study, CDC scientists found that perchlorate exposures far below EPA’s “safe” level were associated with significant thyroid hormone changes in women.
EWG has repeatedly called on EPA to consider this new research when deciding to regulate perchlorate in tap water.
4. I'm pregnant and live in a state with contaminated drinking water. What steps should I take to reduce my exposure?
Call your local water provider and ask if perchlorate has been found in your local tap water supply. If so, EWG recommends that you install a reverse osmosis water filtration system that specifically removes perchlorate.
5. How does the perchlorate get into the powdered cow's milk formula?
As its name implies, cow’s milk based powdered formula is made from cow’s milk, which is known to be widely contaminated with perchlorate. It is currently thought that perchlorate contaminates cow’s milk because cows may drink water and eat foods that are contaminated and the perchlorate then ends up in their milk.
6. I live in a state with perchlorate contaminated drinking water; is it better to use liquid formula instead of powdered?
Liquid formula has its own issues, including possible contamination with BPA, a synthetic estrogen linked to a host of adverse health effects including breast and prostate cancer, infertility, obesity, and behavioral problems in lab studies. At this point, EWG recommends continuing to use powdered formula reconstituted with perchlorate-free water. Please check with your pediatrician before making any changes in the formula you feed your baby.
7. If perchlorate is in powdered infant formula made from contaminated cow's milk, what other food sources - including cow's milk - might contain perchlorate?
The FDA has done testing of almost 300 commonly consumed foods and found perchlorate in almost three quarters of the foods they tested. You can read EWG’s analysis of the FDA study on our web site.
8. Is there any research about perchlorate in other types infant formulas (e.g., soy, liquid)?
This CDC study tested soy based and elemental powdered formula and found perchlorate in these types of formulas also, but at lower concentrations than in the cow’s milk based formula.
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, https://www.ewg.org. 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: www.itrcweb.org/Documents/PERC-2.pdf
13) Environment California. 2006. The Politics of Rocket Fuel Pollution. Available: http://www.environmentcalifornia.org/reports/clean-water/clean-water-program-reports/the-politics-of-rocket-fuel-pollution.
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: www.oehha.org/public_info/facts/faqperchlorate.html.
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: www.clu-in.org/contaminantfocus/default.focus/sec/perchlorate/cat/Toxicology/
19) Environmental Protection Agency. 2008. Fact sheet: Unregulated Contaminant Monitoring Rule 1 (UCMR 1). Available: www.epa.gov/ogwdw/ucmr/ucmr1/factsheet.html
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: http://www.cfsan.fda.gov/~dms/clo4data.html.
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: http://220.127.116.11/search?q=cache:3ttezS120lUJ:www.epa.gov/fedfac/pdf/perchlorate_guidance.pdf+EPA+Assessment+Guidance+for+Perchlorate&hl=en&ct=clnk&cd=1&gl=us&client=firefox-a.
27) U.S. Environmental Protection Agency Children's Health Protection Advisory Committee letter to EPA administrator. 2006. Available: http://www.google.com/search?q=Melanie+Marty+and+perchlorate&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-US:official&client=firefox-a.
28) U.S. Environmental Protection Agency response. 2006. Available: http://18.104.22.168/search?q=cache:5_gSgT3QfD4J:yosemite.epa.gov/ochp/ochpweb.nsf/content/5112006.htm/%24file/5112006.pdf+Melanie+Marty+and+perchlorate&hl=en&ct=clnk&cd=1&gl=us&client=firefox-a.
29) U.S. Environmental Protection Agency, Superfund Sites Where You Live. 2006. Available: http://www.epa.gov/superfund/sites/.
30) Massachusetts Department of Environmental Protection. 2006. Addressing Perchlorate and other emerging contaminants in Massachusetts. Available: http://www.mass.gov/dep/water/drinking/percfs77.htm.
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: http://energycommerce.house.gov/cmte_mtgs/EHM%20042507%20QFRs/CDC.Pirkle.Response.pdf
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: www.cdph.ca.gov/certlic/drinkingwater/Pages/Perchlorate.aspx
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: http://www.epa.gov/safewater/contaminants/unregulated/perchlorate.html