Perchlorate/Safe Drinking Water Act: Institute of Hazardous Materials Management Comments on U.S. EPA's Proposed Primary Drinking Water Regulation

The Institute of Hazardous Materials Management (“IHMM”) submitted March 2nd comments to the United States Environmental Protection Agency (“EPA”) regarding EPA’s proposed Safe Drinking Water Act National Primary Drinking Water Regulation (“NPDWR”) for perchlorate.

EPA published in the January 6th Federal Register the proposed NPDWR for perchlorate. See 91 Fed. Reg. 398.

IHMM describes itself as a not-for-profit organization headquartered in Rockville, Maryland, operating in all 50 states and 85 countries. The organization further states that it has:

… been protecting the environment and the public’s health, safety, and security through the creation of credentials recognizing professionals who have demonstrated a high level of knowledge, expertise, and excellence in the management of hazardous materials, dangerous goods transportation, environmental protection, health, and workplace safety.

Perchlorate is often utilized in signal flares, munitions, fireworks, airbag initiators for vehicles, and solid rocket propellants. However, it can occur naturally in arid regions such as the Southwestern United States. It has been a focus of EPA review for many years.

EPA noted in proposing the NPDWR that it was required to do so by the District of Columbia Circuit Court of Appeals in NRDC v. Regan in 2023. The D.C. Circuit had vacated and remanded EPA’s July 2020 withdrawal of its determination to issue a drinking water regulation for perchlorate.

EPA is proposing a health-based Maximum Contaminant Level Goal (“MCLG”) of 0.02 mg/L. The agency is co-proposing enforceable Maximum Contaminant Level for perchlorate at 0.02 mg/L 0.04 mg/L, or 0.08 mg/L.

IHMM notes that its comments focus on:

• Improving the implementability and legal defensibility of the final rule;
• Ensuring that monitoring, analytical, public-notification, and residuals-management requirements are calibrated to real-world occurrence and exposure pathways; and
• Identifying specific professional practice and ethics implications for IHMM certificants (CHMM, CHMP, AHMM, and related credentials) who will support public water systems (PWSs), primacy agencies, and regulated supply chains.

The organization states that it supports EPA’s proposed MCLG of 20 µg/L, subject to EPA providing additional record clarity on the technical and conceptual role of the 1-point IQ benchmark response used in the derivation and on key exposure assumptions that drive the RfD-to-MCLG translation (DWI–BW and relative source contribution).
Also outlined is IHMM’s alternative approach regarding monitoring scenarios.

IHMM’s comments also recommend that EPA elevate “source control” and chemical stewardship. This is stated to include control of perchlorate formation associated with hypochlorite disinfection chemical storage/handling—into the final rule’s implementation framework (even if not designated as “BAT”). The stated rationale is because this pathway may reduce exposure at comparatively low cost while producing collateral process safety gains.

The organization also asks that EPA ensure the rulemaking record is practically accessible and reproducible. Concern is expressed that an EPA inability to show net positive monetized benefits at any proposed MCL is “highly likely” to become a central litigation issue. Therefore, it asks that EPA publish the CBX model inputs/outputs, occurrence model assumptions, and monitoring-cost allocation details in a way that allows independent replication and meaningful comment.

Clarifications and targeted edits include:

• The automatic monitoring reduction thresholds;
• Composite sampling rules;
• Confirmation sample timing;
• Tiering for public notification; and
• Residuals management expectations for ion exchange, reverse osmosis, and biological treatment.

A copy of the comments can be found here.