Perchlorate: The Two-Decade Journey to a Proposed Rule

Abstract

Perchlorate, a manufactured and naturally occurring chemical, was first detected in drinking water supplies in California in the 1980s. In the 1990s, perchlorate contamination (in the parts-per-billion range) was detected in drinking water supplies across the U.S. EPA began evaluating perchlorate for regulation in drinking water in 1998 and has spent 21 years issuing various proposals and findings on perchlorate, with a proposed (not final) drinking water regulation issued on June 26, 2019. The lack of a drinking water standard has had ramifications, including lack of trust in public drinking water resulting in economic hardship, particularly among Department of Defense personnel and other low-wealth communities, the states setting a patchwork of their own regulations on perchlorate, and lack of monitoring or clean-up of perchlorate in Department of Defense water systems. The reasons for EPA’s two-decade rulemaking process for perchlorate include the process EPA uses to determine regulatory feasibility under the Safe Drinking Water Act and the multi-year scientific review process. Key recommendations for shortening the process include amending the Safe Drinking Water Act and increasing transparency of the rulemaking process. List of Abbreviations: BMDL- Benchmark Dose Level; CCL- Contaminant Candidate List; DOD- Department of Defense; DWEL- Drinking Water Equivalent Level; EPA- Environmental Protection Agency; GAO- General Accountability Office; HRL- Health Reference Level; IRIS- Integrated Risk Information System; LOAEL- Lowest-Observed-Adverse-Effect Level; MCL- Maximum Contaminant Level; MCLG- Maximum Contaminant Level Goal; NOAEL- No-Observed-Adverse-Effect Level; NRC- National Research Council; RfD- Reference Dose; RSC- Relative Source Contribution; SAB-Science Advisory Board; SDWA- Safe Drinking Water Act