Food

Perchlorate Questions and Answers

The following are FAQs on Perchlorate in these topics:

Perchlorate in Food

FDA Testing of Foods for Perchlorate

What Actions are the FDA and EPA taking

Advice for Consumers


Perchlorate in Food

What is perchlorate?

Perchlorate is a negatively charged molecule made of one chlorine atom and four oxygen atoms. Perchlorate can occur naturally or be man-made.

Where is perchlorate found?

Perchlorate occurs naturally in arid states in the Southwest United States (U.S.), in nitrate fertilizer deposits in Chile, and in potash ore in the U.S. and Canada. Perchlorate also forms naturally in the atmosphere. Manufactured perchlorate is used as an industrial chemical and can be found in rocket propellant, explosives, fireworks, and road flares. Because perchlorate is in the environment, it has been found in some drinking water and in some foods. In addition, small amounts of of perchlorate (not to exceed 1.2 percent by weight of the finished polymer) may be used as a component in certain containers and food processing equipment for use in contact only with only certain types of dry foods.

What are the health risks associated with perchlorate exposure?

Human exposure to high dosages of perchlorate can interfere with iodide uptake into the thyroid gland, disrupting the functions of the thyroid and potentially leading to a reduction in the production of thyroid hormone. In fact, perchlorate has been used as a drug to treat hyperthyroidism (excess thyroid hormone production) and to diagnose disorders related to thyroid or iodine metabolism. In adults, the thyroid plays an important role in regulating metabolism. In fetuses and infants, thyroid hormones are critical for normal growth and development of the central nervous system. Pregnant women and their fetuses and newborns have the greatest potential for risk of adverse health effects following exposure to perchlorate.

FDA Testing of Foods for Perchlorate

What testing has the FDA done for perchlorate in food?

Between 2008 and 2012, the FDA collected and tested a total of 5,464 food samples for perchlorate and found no overall change in perchlorate levels across foods compared to 937 samples collected between 2005 and 2006. A further analysis of perchlorate levels per year between 2008 and 2012 also found no consistent change in perchlorate levels across foods from year to year.
The 2008 – 2012 dataset contained higher average levels of perchlorate in some foods such as bologna, salami, and collard greens, and lower average levels of perchlorate in other foods such as plain bagels, boxed macaroni and cheese, and milk chocolate, when compared to the 2005 – 2006 dataset. These differences may be due to a number of factors, including variances in the region or season when the samples were collected and/or the increase in sampling in 2008-2012.

The FDA collected these samples as part of its Total Diet Study (TDS), which analyzes samples of about 280 types of foods, including 40 types of baby food, every year from different parts of the country.

Has the FDA conducted any exposure assessment?

In January 2008, the FDA published a study entitled "U.S. Food and Drug Administration's Total Diet Study: Dietary Intake of Perchlorate and Iodine" in the Journal of Exposure Science and Environmental Epidemiology. This study reports on the estimated average dietary intakes of perchlorate and iodine in 14 age-gender subgroups of the U.S. population based on analytical results for perchlorate from the FDA's TDS samples collected in FY 05-FY06 and for iodine from TDS samples collected in five market baskets from late FY03 through FY04.

In addition, from FY08-FY12, perchlorate and iodine were analyzed in four market baskets per year in about 280 foods. These data were used to determine dietary intakes to perchlorate and iodine in the same age-gender subgroups examined in 2008, and results were published in 2016 in a study entitled “Update on dietary intake of perchlorate and iodine from U.S. food and drug administration’s total diet study: 2008-2012,” in the Journal of Exposure Science and Environmental Epidemiology. The complete set of perchlorate data obtained from FY08-FY12 TDS surveys is available on FDA’s website. Iodine data are available on the Total Diet Study website.

The estimated average intakes of perchlorate for the U.S. populations studied in both these exposure assessments were below the Environmental Protection Agency’s (EPA) perchlorate Reference Dose (RfD) of 0.7 µg/kg body weight (bw)/day. For example, the estimated average intake of perchlorate for infants/toddlers based on the 2008-2012 data ranges from 0.36 to 0.48 µg/kg bw/day. The RfD is an estimate of a daily oral exposure to the human population (including sensitive subgroups) that is not likely to result in adverse health effects during a lifetime. Iodine intakes examined in these two U.S. populations exceeded the recommended estimated average requirements for their respective age groups.

What Actions are the FDA and EPA Taking

What is the EPA doing regarding public drinking water?

In September 2017, the EPA released a draft scientific report: Proposed Approaches to Inform the Derivation of a Maximum Contaminant Level Goal for Perchlorate in Drinking Water. This report links the predictions from the perchlorate Biologically Based Dose Response (BBDR) models to neurodevelopmental effects to inform decision making on perchlorate under the Safe Drinking Water Act.

Scientists from the EPA and the FDA’s National Center for Toxicological Research (NCTR) collaborated to develop this modeling work, which was prompted by recommendations from EPA’s Science Advisory Board in 2013.

The EPA is currently soliciting input on its approach for deriving an MCLG for perchlorate in drinking water based on the BBDR models. The EPA is using an approach recommended by its Science Advisory Board to develop the MCLG. This approach differs from that used by the EPA to derive the interim health advisory for perchlorate in drinking water of 15 ppb in 2008.

Following the establishment of the MCLG, the Safe Drinking Water Act requires the EPA to set an enforceable standard. In most cases, the standard is a maximum contaminant level (MCL), which must be set as close in value to the MCLG as feasible taking the costs and benefits into consideration.

If the EPA establishes an MCL for drinking water, will the FDA establish an allowable level for bottled water?

If the EPA establishes an MCL, the FDA is required (under section 410(b)(1) of the Federal Food, Drug, and Cosmetic Act (the FD&C Act)) to issue a standard of quality regulation for perchlorate in bottled water or make a finding that such a regulation is not necessary to protect the public health because perchlorate is contained in water in public water systems, but not in water used for bottled water. The FDA is required to take such action not later than 180 days before the effective date of EPA’s MCL.

If the EPA develops an MCLG for perchlorate based on the new model will that change how the FDA evaluates the safety of foods?

The FDA uses the most up-to-date science, including information from the EPA, when it conducts safety assessments. The FDA will review the new information if and when it becomes available, and see how best to incorporate it in its scientific review, including safety assessments of foods. The FDA will consider future testing for perchlorate in foods in light of the re-assessment at EPA.

What use of perchlorate is authorized in food contact applications?

As of May 4, 2017, perchlorate may only be used up to a certain level as a component of antistatic agents used in certain containers and food processing equipment in contact with only certain dry foods. Any future proposed food additive use of perchlorate in food contact applications is subject to pre-market review and approval by the FDA.

Advice for Consumers

Should I supplement my diet with iodine supplements to protect against potential perchlorate exposure?

In general, most Americans consume adequate amounts of iodine in their diets and taking iodine dietary supplements is not necessary to protect you from perchlorate at the levels present in water and foods. However, you should discuss any specific dietary needs or concerns with your health care provider.

Should pregnant women and infants supplement their diets with iodine?

Iodine is necessary for a baby's normal brain development, so it is particularly important for pregnant and nursing women to get adequate amounts of iodine. Many over-the-counter and prescribed prenatal supplements contain iodine. For infants, breast milk and infant formulas are good sources of iodine. Women and parents of infants and young children should consult their health care practitioners before supplementing their diet or the diet of their children with iodine.

Can I prepare my child’s infant formula using tap water?

Tap water is regulated by the EPA under the Safe Drinking Water Act. In December 2008, the EPA issued its interim health advisory to assist state and local officials in addressing local contamination of drinking water supplies from perchlorate. If you live in one of the few areas where perchlorate in the public drinking water is at levels above 15 parts per billion, the FDA recommends using water that is lower in perchlorate levels, such as bottled water or water from a home treatment device certified for perchlorate removal, to reconstitute your infant's formula.


View a previous version of the FAQs from May 2017.

Page Last Updated: 12/27/2017
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