EPA proposes limits on hypochlorite bleach to reduce degradation to perchlorate

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

Every 15 years, the Environmental Protection Agency’s (EPA) Office of Pesticide Programs (OPP) reviews the safety of registered pesticides. The current cycle ends in 2022. As part of that process, the agency is evaluating the safety of hypochlorite bleaches. In January 2017, EPA decided it would consider the risks posed by degradation of the hypochlorite into perchlorate.

This is important for two reasons: 1) degraded bleach is less effective as a pesticide, and 2) perchlorate is a chemical that interferes with the production of thyroid hormone, a critical hormone for fetal and infant brain development.

On September 22, EPA proposed changes to the pesticide label to minimize the degradation for hypochlorite bleach used to disinfect drinking water, and the agency is accepting comments until November 21, 2017. The label would advise users to:

  • Minimize storage time;
  • Maintain pH of the solution between 11 to 13;
  • Minimize exposure to sunlight;
  • Store at lower temperatures; and
  • If practical, dilute with cool softened water upon delivery.

EDF submitted comments to EPA supporting EPA’s proposal and requesting specific changes to the proposed language, including making the advice to users mandatory. We also asked the agency to extend the label requirements to hypochlorite bleach used to treat produce and to disinfect food handling equipment. Bleach appears to be one of several significant sources of perchlorate contamination of food. Improving management conditions will reduce degradation and preserve effectiveness regardless of the whether the bleach is used in drinking water or to treat vegetables.

EPA’s proposal is an interim decision. We also were pleased to see that OPP is committed to continue working with EPA’s Office of Water (OW) in its assessment of the risks of perchlorate to pregnant women and young children. We asked OPP to incorporate the OW’s findings in additional interim registration decisions for all uses of hypochlorite bleaches.

 

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