Monthly newsletter Material Concerns: Legal Updates on Substances of Emerging Concern keeps clients informed on the latest legal, regulatory and scientific developments related to substances of emerging concern. Each issue delivers concise, actionable insights to help companies navigate the evolving landscape of environmental law.

EPA Rescinds Its Greenhouse Gas Endangerment Finding

By Jennifer Hackman

In a sweeping shift in climate policy, the U.S. Environmental Protection Agency (EPA) finalized a rule rescinding its 2009 Greenhouse Gas (GHG) Endangerment Finding—the determination that emissions of certain GHGs pose a threat to public health and welfare, and therefore may be regulated under the Clean Air Act (CAA). The repeal, finalized on February 12, 2026, eliminates the foundation for federal GHG standards that cover vehicles, power plants and other emission sources.

The 2009 Endangerment Finding was adopted in response to the Supreme Court’s decision in Massachusetts v. EPA (2007). In that case, the Court held that GHGs fall within the CAA’s broad definition of “air pollutant” and that EPA must determine—based on science and statutory factors—whether GHG emissions endanger public health or welfare. The Court did not require EPA to regulate GHGs, but directed the agency to make an endangerment determination or provide a reasoned explanation for declining to do so. EPA’s 2009 finding that certain GHGs pose risks to public health and welfare underpinned subsequent EPA climate regulations.

With the federal government no longer recognizing the Endangerment Finding as a basis for GHG regulation, the CAA framework for national climate rules has been significantly narrowed. EPA has indicated that GHG standards and related provisions promulgated after 2009 for light, medium and heavy duty vehicles are rescinded. EPA explained that there is no CAA authority to regulate GHGs for climate purposes absent an Endangerment Finding. 

This major shift is already triggering responses from states, many of which are preparing to maintain or strengthen their own emissions standards—particularly in California, New York and other jurisdictions with established climate programs. Litigation challenging the repeal has been filed already, with more challenges likely. 

As with other areas of evolving science and regulatory approaches—such as those involving emerging contaminants—GHG regulation is likely to remain dynamic. Federal climate policy—often shaped by the political landscape—has shifted significantly with this administration’s recent action, mirroring the uncertainty seen in regulatory approaches to PFAS, microplastics, and other developing environmental concerns. Potential divergence between federal and state regimes may create patchwork compliance conundrums for multistate operators. To navigate this shifting landscape, stakeholders should consider monitoring state regulatory developments, preserving data continuity in the event of future federal reinstatement, and actively engaging in rulemaking comment processes, as state agencies initiate new climate related proposals in light of EPA’s recent action.

California Proposes Listing Dish Detergents and Shampoos Containing 1,4-Dioxane as Priority Products Under Safer Consumer Products Program

By Joseph Zaleski

The California Department of Toxic Substances Control (DTSC) enforces the state’s Safer Consumer Product (SCP) regulations, adopted in 2013 to implement the California Green Chemistry Law enacted in 2008. The SPC program was designed to identify consumer products that contain “chemicals of concern” and to evaluate whether safter alternatives or product design features are feasible. DTSC is now proposing, for the first time, to list and administratively review certain personal care and cleaning products that contain the chemical 1,4-dioxane as “Priority Products” subject to administrative review under the SPC regulations. The SCP regulations outline a stepwise approach for DTSC to list and then assess a range of regulatory responses for consumer products that contain one or more chemicals of concern. After DTSC formally lists a consumer good as a Priority Product, manufacturers of the product available for purchase in California must complete and submit to DTSC a life-cycle analysis to determine whether the identified chemical can be reduced, eliminated or replaced with safer alternatives or whether other product design changes could reduce potential adverse impacts. DTSC may then select regulatory actions ranging from taking no further action, to requiring additional product information or labeling for consumers, all the way up to imposing product use restrictions or sale prohibitions in the state.

In late January 2026, DTSC initiated the administrative process of listing as a Priority Product any manual detergents and shampoos containing 1,4-dioxane in excess of one part per million. DTSC has long identified 1,4-Dioxane as a candidate chemical, but this is the first time DTSC has cited that chemical in a Priority Product listing proposal. 

Nevertheless, DTSC’s move was not unexpected—in its 2024-2026 Priority Product Work Plan, DTSC named beauty, personal care and hygiene products as key priorities for the coming years, specifically identifying 1,4-dioxane as a candidate chemical DTSC would assess. In 2019, DTSC held public workshops on the presence of 1,4-dioxane in personal care products, and in 2024 DTSC released a draft technical assessment document to support regulatory action on Priority Products containing 1,4-dioxane. 

According to DTSC’s technical assessment, 1,4-dioxane is a “persistent, mobile, and toxic” chemical that is highly soluble in water and mobile in both the aquatic environments and soil. The report explains that 1,4-dioxane contamination in personal care and cleaning products frequently occurs as a byproduct of the ethoxylated surfactants commonly used as ingredients. Because these types of products can be washed down drains during and after normal use, 1,4-dioxane may potentially enter soil, soil vapor and groundwater. The report notes that, at present, “[m]ost standard forms of wastewater treatment and drinking water treatment do not remove 1,4-dioxane.” 

Separately, other California agencies, acting under different legal authorities, have begun to establish various criteria and standards to regulate 1,4-dioxane in drinking water, reflecting a broader statewide focus on the chemical.

DTSC is taking public comment on this proposal until March 2, 2026. DTSC has not yet scheduled a public hearing on this proposal, but it may do so if requested during the public comment process. In California, agencies typically have one year to finalize a rulemaking action after the date of proposing the action. Assuming this Priority Product listing is finalized, the next SCP regulatory requirements for an alternatives analysis and DTSC regulatory response consideration will be triggered. 

Alabama Enacts Law to Govern State-Level Environmental Regulation and Set “Best Available Science” Threshold

By Joseph Zaleski 

On February 20, Governor Kay Ivey of Alabama signed into law SB 71, which establishes new requirements for state regulators attempting to set state-level numeric criteria or limits under certain key environmental laws. In general, the new law prevents Alabama environmental regulators from adopting numeric criteria or numeric limitations for drinking water, water pollution control, hazardous substances, contaminated site remediation, air quality, solid waste handling, or hazardous waste handling that are more stringent than comparable rules set by federal regulators.

If a state environmental regulator chooses to set numeric criteria or limitations in the absence of a comparable federal standard, this law requires that the new criteria be based on the “best available science” and the “weight of scientific evidence,” which are specifically defined terms. Rules pertaining to human health have more stringent requirements that must be met—namely, the law requires that the best available science and the weight of scientific evidence must “establish a direct causal link between exposure at or above the numeric criteria or numeric limitations provided by the rule and manifest bodily harm in humans, based on generally accepted scientific or technical practices.” These requirements will likely govern any future state-level attempts to regulate substances of emerging concern, especially in situations where federal regulators have not yet taken regulatory action on substances of emerging concern.

Separately, the law provides that state agencies that establish water quality criteria may not use the EPA’s values under the Integrated Risk Information System (IRIS) as a default or the basis for action and that if water quality criteria have already been established using IRIS values then the state agency must reconsider the level consistent with the provisions of SB 71.

This law does not apply to rules that are required by federal law or regulation, rules that are less stringent than applicable federal rules, rules that would repeal or modify an existing rule to be less stringent or extensive in scope, coverage, or effect, or to emergency rules. Tennessee enacted a similar law (SB 880)—called the Sound Science in Regulations Act—in 2025.

EPA Establishes New PFAS Coordinating Group

By Kate Klaus

On February 6, 2026, the U.S. Environmental Protection Agency (EPA) announced plans to establish a PFAS coordinating group. 

According to the agency, the new group will help coordinate PFAS-related research, technology development and cleanup efforts. Members will include senior technical and policy leaders from across EPA, including the Office of the Administrator and the Office of Water. 

The group is also intended to support agency actions to address PFAS under the major federal environmental laws. Specifically, the announcement highlighted anticipated efforts to:

• Regulate chemicals under the Toxic Substances Control Act.
• Set drinking water standards under the Safe Drinking Water Act.
• Clean up contamination exceeding safe levels at Superfund sites.
• Control pollution from industrial sources under the Clean Air Act and Clean Water Act.

In addition to these actions, the EPA emphasized the importance of advancing accurate and reliable methods for detecting and treating PFAS across environmental media.

The announcement also recapped EPA’s key PFAS actions during the first year of the Trump Administration, describing these steps as “just the beginning” of a broader PFAS initiative that remains a “top agency priority.”