EPA to consider perchlorate risks from degradation of hypochlorite bleach

Tom Neltner, J.D.is Chemicals Policy Director and Maricel Maffini, Ph.D., Consultant

Virtually all types of food contain measurable amounts of perchlorate. Young children are the most highly exposed, and they consume levels that may be unsafe. Reducing exposure to perchlorate is of public health importance because it presents a risk to children’s brain development

One potentially significant source of the toxic chemical in food is hypochlorite bleach that, when not well managed, degrades to perchlorate. Bleach is used to sanitize food manufacturing equipment or to wash or peel fruits and vegetables. Thanks to a recent decision by Environmental Protection Agency’s (EPA) Office of Pesticide Programs, we will better understand the risk posed by perchlorate-contaminated bleach and whether standards are needed to improve the management of bleach.

Reduce perchlorate exposure by improving bleach management

In 2011, an excellent report by the American Water Works Association (AWWA) and the Water Research Foundation documented that hypochlorite bleach degrades into perchlorate. The report also included guidelines on better management of hypochlorite to preserve its effectiveness for drinking water utilities using it to disinfect water.

Most of AWWA’s recommendations are equally relevant to food manufacturers and anyone using bleach to disinfect food contact surfaces. The key recommendations are:

  • Dilute hypochlorite solutions on delivery. Cutting the concentration in half decreases the degradation rate by a factor of 7.
  • Store hypochlorite solutions at lower temperatures. Reducing temperature by 5oC decreases degradation rate by a factor of 2.
  • Keep pH between 11 and 13 even after dilution.
  • Avoid extended storage times, and use fresh hypochlorite solutions when possible.

The objective is not to reduce the use of bleach. Rather it is to preserve its effectiveness by preventing degradation to perchlorate through careful management.

Bleach: a food additive and a pesticide

Both the Food and Drug Administration (FDA) and the EPA regulate uses of bleach. When hypochlorite bleach is used to wash or peel fruits and vegetables, it is a food additive regulated solely by FDA. When it is used to sanitize (e.g., water, surfaces or equipment in contact with food), it is a pesticide that must be registered with EPA. Calcium and sodium hypochlorite are both FDA-approved food additives and EPA-registered pesticides. Unlike food additives, the safety of pesticides used in food must be reassessed periodically through what is called registration review. EPA’s review must consider exposures from all uses.

In 2013, EPA was completing a periodic reregistration review of sodium and calcium hypochlorite bleaches when the Natural Resources Defense Council (NRDC) asked EPA’s Office of Pesticide Program to consider the degradation of the products into perchlorate – something that the agency had not considered previously. In 2016, EDF and NRDC reminded EPA of the request. On January 19, 2017, EPA expressed an intention to “take an in-depth look at the requests in your letter, including whether any action is appropriate under the Federal Food Drug and Cosmetic Act (FFDCA), and to consider, among other things, possible labeling language to optimize storage of hypochlorite products in order to minimize perchlorate and chlorate formation during storage.”


With perchlorate in food increasing to levels that may cause irreversible harm to brain development in young children, EPA’s review is a welcome opportunity to reduce exposure. But the process will likely take years to complete. In the meantime, food manufacturers using hypochlorite bleach should take action now using the available common sense recommendations to preserve the effectiveness of the bleach and prevent its degradation into perchlorate.

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