Thirty state legislatures are now on record asking the U.S. Environmental Protection Agency to retain Clean Air Act protections covering pyrolysis facilities, the National Caucus of Environmental Legislators (NCEL) confirmed this week.

The sign-on letter, coordinated by NCEL and addressed to EPA leadership, urges the agency to preserve its current regulatory framework for pyrolysis — a thermochemical process that heats plastic waste in low-oxygen environments to recover feedstocks or fuel. NCEL's announcement did not include the full text of the letter or the list of individual signatories.

What is the regulatory dispute about?

Pyrolysis and related depolymerization processes sit at the center of a multi-year classification fight. EPA's current interpretation applies Section 129 of the Clean Air Act to facilities that thermally convert plastic scrap, subjecting them to emission limits for dioxins, furans, particulate matter, hydrogen chloride and mercury, along with continuous emissions monitoring.

Industry petitioners have asked EPA to reclassify advanced recycling units as manufacturing under Section 112 of the act, which governs hazardous air pollutants and applies different — and, operators argue, less onerous — control standards. Reclassification would drop the "solid waste incineration" label and the Section 129 compliance burden that operators describe as poorly suited to feedstock-recovery processes.

State signatories counter that pyrolysis units emit combustion byproducts indistinguishable from those of traditional incinerators and should remain under Section 129 oversight, particularly when sited near residential or fenceline neighborhoods.

Who organized the state push?

NCEL coordinated the letter. The organization convenes state-level environmental legislators and has previously organized cross-state sign-ons on chemicals policy, per- and polyfluoroalkyl substances (PFAS) and power-plant emissions.

NCEL's stated membership covers legislators from 30 states, matching the count cited in the pyrolysis letter. The sign-on therefore represents the organization's full geographic reach rather than a regional subset.

Why does classification matter to operators?

Pyrolysis is scaling rapidly as chemical and energy companies seek to monetize mixed plastic scrap that mechanical recyclers reject. Announced U.S. capacity from major petrochemical operators — including Eastman Chemical's Kingsport, Tenn. complex, ExxonMobil's Baytown-area projects and Brightmark's plastic-to-fuel facilities — is measured in tens of thousands of tons of plastic feedstock per year, though commissioning schedules for several of those projects have slipped.

Capital allocation depends materially on which Clean Air Act section applies. Section 129 requires ash handling protocols, continuous emissions monitoring and siting analyses equivalent to those for municipal solid waste combustors. Section 112 replaces those requirements with maximum achievable control technology (MACT) standards but does not label the units as incinerators, simplifying permitting and, operators argue, shortening project timelines.

Investors and operators have favored the Section 112 pathway. Fenceline community groups, downstream mechanical recyclers and the 30 sign-on states have favored Section 129 retention.

What happens next?

The letter's near-term weight depends on whether EPA has an active proceeding in which to consider it. The agency's 2023 advanced recycling framework left pyrolysis classification largely intact, but petitions seeking Section 112 treatment remain pending at the Office of Air and Radiation.

Industry counsel expect EPA to address those petitions through notice-and-comment rulemaking rather than informal guidance, which would generate a public record state legislators and community groups can use to argue against reclassification in formal comments.

The next milestone: EPA's formal response to the pending Section 112 petitions, which will determine whether the 30-state objection becomes a docketed comment or — if the agency moves toward reclassification — triggers a state-level permit fight at individual project sites.