States File Amicus Brief Supporting EPA's PFAS Regulations

Dr Steven Brennan
Dr Steven Brennan
3 min readAI-drafted, expert reviewed
Drinking water

Key takeaway

What This Development Means

A coalition of states has filed an amicus brief supporting the EPA's PFAS regulations, highlighting the importance of public health protection. The brief endorses the use of a hazard index to assess PFAS risks and addresses industry concerns about compliance costs.

What is the purpose of the states' amicus brief on PFAS regulations?

The amicus brief supports the EPA's PFAS regulations, emphasising the importance of public health protection. It highlights the states' role in enforcing drinking water standards and complements existing state efforts to regulate PFAS.

How does the hazard index factor into the EPA's PFAS regulations?

The hazard index is a key component of the EPA's rule, assessing the combined risk of PFAS mixtures. It ensures that the sum of hazard quotients for individual PFAS does not exceed a unitless value of 1, providing a comprehensive health risk assessment.

Source basis: https://portal.ct.gov/-/media/ag/press_releases/2025/20250117-amicus-brief-filed.pdf?rev=9f622ce1a8794172ab8ad1f7cf9ab3c9&hash=BAB403B2663AFE786C04959B1C3EDFE4

On 17 January 2025, a coalition of states, including Connecticut, California, and New Jersey, filed an amicus brief in support of the United States Environmental Protection Agency's (EPA) new regulations on per- and polyfluoroalkyl substances (PFAS) in drinking water. The brief underscores the states' commitment to public health and environmental protection.

The Coalition Of States And Their Interests

The amicus brief was submitted by a group of states, including Connecticut, California, New Jersey, and others, collectively known as the State Amici. These states have a vested interest in the EPA's rule due to their roles in enforcing drinking water standards and operating public water systems. The brief highlights the states' collective ownership of 2,482 public water systems, with 353 subject to the new PFAS regulations.

Supporting The EPA's Public Health Mandate

The State Amici argue that the EPA's rule aligns with the Safe Drinking Water Act's public health mandate by addressing contaminants of concern. The brief emphasises the importance of regulating PFAS, which are linked to various health risks, including cancer and liver damage. The states assert that the rule provides a necessary federal baseline for PFAS regulation, complementing existing state efforts.

The Role Of The Hazard Index In Regulation

A key component of the EPA's rule is the use of a hazard index to assess the risk of PFAS mixtures. The amicus brief supports this approach, noting that it is a practical means to prevent dose-additive harms from PFAS mixtures. The hazard index is set at a unitless value of 1, ensuring that the combined risk of multiple PFAS does not exceed safe levels.

Addressing Industry And Utility Concerns

The brief also addresses concerns raised by industry and utility petitioners, who argue that the rule's economic analysis is flawed. The State Amici counter that the EPA's analysis is consistent with the Act's requirements and that the rule's benefits to public health justify the costs. The states emphasise the importance of affordability and the practical significance of safe drinking water.

The Broader Impact Of The Amicus Brief

By filing the amicus brief, the State Amici demonstrate their commitment to upholding the EPA's rule and protecting public health. The brief reinforces the cooperative federalism framework of the Safe Drinking Water Act, highlighting the states' role in ensuring safe drinking water for their residents. The coalition's support underscores the widespread recognition of PFAS as a significant public health concern.

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