The plastics pyrolysis policy war may soon spill into the states

A press release that the US Environmental Protection Agency published March 17 about debris and natural disasters seemed like just another minor announcement.

The agency was proposing two new actions, the release said, that would relax permitting rules for air curtain incinerators so communities could clean up faster after emergencies. Both actions seemed unimportant to the 30-year-old fight over air pollution rules for a type of chemical recycling called pyrolysis.

But there was something else in the EPA’s proposal. In section VI, more than midway through the document, was a third action not mentioned in the press release:

“The EPA is soliciting comment on revising the definition of ‘municipal waste combustion unit’ in the OSWI [other solid waste incinerator] NSPS [new source performance standards] and EG [emission guidelines] to remove the reference to ‘pyrolysis/combustion units.’ ”

Within this bureaucratic language lay a potential major development. If “pyrolysis/combustion units” were removed from this definition, they would no longer be classified as incinerators and no longer be subject to the strict hazardous air pollutant (HAP) emission limits in section 129 of the Clean Air Act (CAA).

Getting pyrolysis units out of section 129 is something the plastics industry has been trying to do for years, says Jessica Roff, plastics and petrochemicals program manager for the Global Alliance for Incinerator Alternatives (GAIA), an environmental advocacy group. During President Donald J. Trump’s first term, the EPA proposed a change that was almost identical to the March proposal. But under the Joe Biden administration, the EPA withdrew the change.

“To have it just be this off-handed comment buried two-thirds of the way through a document that makes no reference to anything else about pyrolysis or gasification, other than in that one paragraph,” she says. “It’s bonkers, how much this was hidden.”

The window for comments closed on May 4, but not before eliciting over 55,000 responses. According to the EPA’s latest semiannual regulatory agenda, the final rule was expected in July 2026, but it hasn’t been announced yet.

Pyrolysis thermally breaks down plastics under low oxygen to make pyrolysis oil, or pyoil. This oil can be made into fuels or chemical building blocks for new materials. Pyrolysis can also create incomplete combustion products that are hazardous to human health, such as dioxins, polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAHs).

The plastics industry and industry groups such as the American Chemistry Council (ACC) say the CAA section 129 regulations are too strict and are getting in the way of chemical recycling innovation. The ACC has been lobbying states to pass laws saying that chemical recycling is manufacturing and that facilities shouldn’t be regulated as solid waste incinerators. The group has been successful most of the time.

Environmental and community advocates say pyrolysis facilities are too dangerous to take out of section 129. Air permits for manufacturing facilities might not require rigorous monitoring for some of the more toxic air pollutants from pyrolysis facilities, which would leave communities surrounding the facilities at risk, environmental and community advocates contend. They say the plastics industry is pushing chemical recycling as a solution to the plastic pollution problem, when it’s really an excuse for the industry to keep making plastic.

If the EPA does remove pyrolysis units from section 129, how will their air emissions be regulated? Supporters of the move say they’d fall under another part of the CAA. Opponents say there’s nothing in the proposal or current laws that says they would. Instead, regulation might be left up to the states, which have uneven rules about plastics pyrolysis facilities, or none at all. 

Pyrolysis plants and the Clean Air Act: In theory

The EPA regulates a stationary source of air pollution if the source emits more than a certain amount of air toxics, says Jane Williams, executive director of the advocacy group California Communities Against Toxics.

Air toxics are dangerous chemicals that can cause acute harm to human health. The EPA regulates close to 200 such compounds, also called hazardous air pollutants (HAPs). The list includes carcinogens, compounds that cause reproductive and developmental effects, neurotoxic compounds, and more.

The EPA usually considers a facility that generates either 9.1 metric tons (t) (10 US tons) per year of any single HAP, or 22.7 t (25 US tons) of combined HAPs, as a major source. In general, facilities that generate less than this are minor sources. The EPA regulates HAPs emissions under CAA sections 112 and 129. There are some exceptions, but most stationary sources are listed and regulated under section 112. Specific emission requirements differ and depend on the source category.

Except incinerators. They fall under section 129. This is by design, Williams says.

When Congress was writing amendments to the CAA in the 1990s, the authors realized that incinerators wouldn’t be properly regulated, she says. “There’s a special provision in the [Clean Air] Act for incinerators because their emissions are so uniquely toxic,” Williams says.

Also, incinerators might not emit enough of a combined or single HAP to be regulated by section 112. “So they decided, ‘We’re just going to write a special part of the act so it covers incinerators,’ and that’s what section 129 is,” she says.

This incinerator designation means that pyrolysis units must get a stringent type of air pollution permit called a Title V or major-source permit.

“You need a Title V major-source air permit if you combust solid waste,” says James Yskamp, senior attorney for the advocacy group Earthjustice. “So even for very small municipal waste combustion, whether it’s plastic, whether it’s any other type of waste, they still need a major-source permit,” he says.

Companies try to avoid Title V permits. “There are more limits, and more monitoring and reporting” requirements, Yskamp says.

Under section 129, some incinerators have other specific emission limits for HAPs and other compounds. But generally, the section lays out limits for nine substances: cadmium, carbon monoxide, dioxins and furans, hydrogen chloride, lead, mercury, nitrogen oxides, particulate matter, and sulfur oxides.

Federal air regulations are complex, and it’s hard to know what would happen if the EPA removes pyrolysis/combustion units from section 129, Yskamp says. But if that removal does happen, it’s likely that the specific section 129 emission limits would no longer apply to pyrolysis facilities, he says.

The Clean Air Act in practice: It’s complicated

“The Clean Air Act is really tough to try to condense,” Yskamp says. Because of the way section 129 is designed, pyrolysis/combustion units are considered major sources even if they don’t emit enough pollution to get over the law’s major-source threshold. If the agency takes pyrolysis/combustion units out of section 129, they’ll probably be downgraded to minor sources. In general, the downgrade to minor source means they’re no longer in federal jurisdiction, Yskamp says.

“It’s one of these circumstances where it just falls through the cracks of federal regulations,” Yskamp says.

Supporters of removing pyrolysis facilities from section 129 say they’ll be covered by section 112 instead. But remember that the specific requirements of section 112 regulations depend on the stationary-source category, Yskamp says. “There is no category for these pyrolysis facilities,” he says.

To regulate pyrolysis facilities under section 112, the EPA could add pyrolysis/combustion units as a new source category. But this is unlikely, Williams says. The current list of source categories was set shortly after the 1990 CAA amendments, she says. “Those have not been added to since.”

Another way to regulate pyrolysis facilities under section 112 would be to roll them into an existing stationary-source category. But this action isn’t straightforward either.

“There isn’t one clear-cut provision that covers these facilities,” Matthew Kastner, senior director of media relations at the ACC, told C&EN in an email in April.

“It depends more on what is happening at the specific operational level,” he wrote. For example, Kastner said, some pyrolysis facilities could be classified as miscellaneous organic chemical manufacturing facilities or as a chemical manufacturing area source. Carla Toth, vice president of sustainability and advocacy for Nexus Circular, which runs a pyrolysis facility in Atlanta, says her firm’s facility could be regulated as a stationary reciprocating internal combustion engine under section 112.

But in its March proposal, the EPA asked only for public comment on whether “pyrolysis/combustion unit” should be taken out of the definition of “municipal waste combustion unit.” The notice did not recommend what section of the CAA the units should fall under or suggest how they’d be regulated in the future.

So where does that leave the regulation of pyrolysis facilities? With the states, Yskamp says. “If [pyrolysis/combustion units are] not a municipalized combustion unit or a combustion unit, and EPA hasn’t developed a category for these, it’s really up to the state how to regulate them, as long as their emissions thresholds fall below the major-source thresholds,” he says.

Some states may have been preparing for this.

What do the states say?

As of Sept. 30, 29 states have laws that define chemical recycling, which includes pyrolysis facilities, or how to regulate it. Twenty-six of them have passed legislation defining chemical recycling in one of three ways: as manufacturing, as not solid waste processing, or as manufacturing and not solid waste processing.

Three states—Maine, New Mexico, and California—have passed laws saying that chemical recycling is defined as solid waste processing and should be regulated as such.

The ACC, which has been actively lobbying state legislatures in support of laws defining chemical recycling as manufacturing instead of solid waste processing, declined C&EN’s request for an interview on its efforts. “ACC will continue supporting policies that enable more mechanical and advanced recycling because we need every available tool to keep more plastic in productive use,” Ross Eisenberg, president of the group’s Plastics Division, says in an emailed statement.

So if the EPA removes pyrolysis/combustion units from section 129 of the CAA, and a state has already passed a law saying chemical recycling is manufacturing, or not solid waste processing, then any pyrolysis facility in the state probably wouldn’t have to comply with section 129, Yskamp says.

But how the shift in authority would play out is complicated, he says. “It depends on how the state regulates the activity,” Yskamp says. Some of the laws in the 26 states that regulate chemical recycling as manufacturing or not solid waste processing have similar text and wording, but some are very different.

In the states that have laws saying pyrolysis is solid waste processing, something similar to section 129 or more stringent probably would still apply. It depends on how the laws are worded, Yskamp says.

But 21 states don’t have specific laws regarding chemical recycling. What would the removal of pyrolysis units from section 129 mean in those states?

Again, it’s not clear, Yskamp says. If a state wants to regulate chemical recycling in a specific way, state lawmakers would have to scramble to get something passed, he says. Otherwise, pyrolysis units in that state would need some kind of minor-source permit. And his experience with other minor-source state air permits is that they usually have minimal monitoring and reporting requirements.

“It’d be very relaxed regulation, especially compared to anything else that would combust plastic,” he says.

If the EPA’s proposal does become a final rule, it’s hard to say if this federal decision will significantly change how states think about pyrolysis facilities and choose to classify them, says Veena Singla, an affiliate at the University of California, San Francisco, Program on Reproductive Health and the Environment. “Generally, what I see in [the air permitting] process is that states will often grant the facilities the designation they ask for in the permit application,” Singla says.

It’s important to note that as of right now, pyrolysis/combustion units are still in section 129 and still regulated as incinerators, she says. “That means that current laws and regulations remain in force, as they have been for years,” Singla says. Federal laws overrule state laws, so a state can’t legally regulate a pyrolysis facility as manufacturing while the federal government still regulates them as solid waste incinerators under section 129.

“A state can be more protective than the federal Clean Air Act, but it can’t be less protective,” Yskamp says.

On the other hand, if Congress passes a federal law defining chemical recycling as manufacturing or otherwise changing how pyrolysis/combustion units are regulated, that law would preempt any state laws. There have been many attempts to pass such a federal law, Williams says, but nothing’s gone through yet. “There’s not really been much appetite in Congress on this,” she says.

A bill currently in Congress, H.R. 7502, the Recycled Materials Attribution Act of 2026, mostly deals with using a calculation called mass balance to determine how companies present recycled-material claims on product packaging. But it also defines “non-mechanical recycling” as a process that “alters the chemical structure of the material and that produces an output used to manufacture products.”

This bill is interesting in that it defines recycling but doesn’t expressly tie it to the CAA, says Mark Duvall, a principal attorney at Beveridge & Diamond. It’s unclear if this bill would have a substantial impact on how pyrolysis units are regulated, he says. “It might be somewhat influential, but I don’t know that there’s a lot there because it’s really addressing a different issue.”

An older bill, H.R. 6566, the Recycling Technology Innovation Act, would redefine solid waste incineration units in CAA section 129 to exclude all types of chemical recycling, including pyrolysis. The bill was sponsored by Rep. Dan Crenshaw (R-TX), but its future is unclear since in March, Crenshaw lost his primary campaign for reelection.

C&EN reached out to several lawyers who represent industry interests on chemical recycling and legal interpretation of the CAA. None agreed to be interviewed.

Why does it matter how pyrolysis facilities are regulated?

The plastics industry says chemical recycling is manufacturing and shouldn’t be regulated as solid waste processing. “ACC supports state and federal policies that appropriately regulate advanced recycling as manufacturing, including pyrolysis,” Eisenberg says in the ACC’s emailed statement to C&EN. “Pyrolysis facilities are like any other manufacturing facility that adds value to inputs by creating something new with them to sell as a product.”

But environmental advocates disagree. They say pyrolysis of plastics puts out too many toxic emissions and will harm people’s health if the facilities are regulated as manufacturing instead of incineration.

Singla points to pollution, transparency, and finances as the three main ways that regulating pyrolysis as incineration differs from regulating it as manufacturing.

“There are more limits around particular pollutants, and the requirements to measure and monitor particular pollutants, if it’s an incinerator versus if it’s manufacturing or recycling,” she says. In general, getting a Title V air permit for an incinerator means that the facilities must install ways to control emissions for compounds such as dioxins and certain heavy metals, Singla says.

Title V permits require that facilities regularly test their smokestacks for regulated compounds, Williams says. “Then they have to certify they’re in compliance with those emission limits,” she says. The facilities also must certify that they’re in compliance with the emission limits on a compliance certification document. “If they lie on it, they could go to federal prison,” Williams says.

The emission limits that pyrolysis/combustion units have under section 129, and requirements to control those emissions, aren’t necessarily going to be in air permits for manufacturing facilities, Singla says.

Toth from Nexus Circular says plastics pyrolysis is different from solid waste incineration, so different emission standards should apply. Section 112 would regulate pyrolysis plants “equally” to solid waste incinerators and “appropriately for the differences in our processes,” she says.

Incinerator permits also have public transparency requirements that manufacturing permits lack, Singla says. For instance, a Title V permit requires that draft air permits are released to the public and that a public hearing is held so the local community can comment and ask questions. “There’s not as much opportunity for the community to engage in the process and provide their input around that particular facility” when it’s regulated as manufacturing, she says.

The last way that manufacturing and incineration air permits differ is cost. “There’s more monitoring and reporting,” compared with a typical manufacturing facility permit, Yskamp says. Title V and section 129 regulations with strict requirements take more staff hours and more sophisticated technology to comply with, which can translate to higher costs.

Toth says many permitting requirements for solid waste facilities don’t make sense for pyrolysis facilities, such as requiring a 10-year plan to service and manage waste in a geographical area. This is an inappropriate investment of time, she says.

Costs are already a problem for pyrolysis facilities, some of which are shuttering because of bankruptcy, production issues, or other operational problems. In the past year, three newer pyrolysis plants in the US—Brightmark, Freepoint Eco-Systems, and Braven Environmental—have closed.

Is chemical recycling a solution to the plastic waste problem?

The ACC does not mention cost in its statements about regulations for pyrolysis or chemical recycling. The group says section 129 requirements stand in the way of innovation. “The input for pyrolysis is plastics that would otherwise be destined for disposal, which are converted into pyrolysis oil and then can be sold to make new products,” Eisenberg says in the ACC’s emailed statement to C&EN.

Recent reports by advocacy groups Beyond Plastics, International Pollutants Elimination Network (IPEN), and the Minderoo Foundation (PDF) say that very little pyrolysis oil is being made into new plastic. Of the marketable products the plants are making, most are oils that, after cleaning, are burned as fuel on-site or sold to third parties, the reports say.

“Ultimately, a barrel of pyrolysis oil (pyoil), regardless of its final fate, displaces a barrel of virgin crude extracted from the ground, and makes use of an untapped waste stream that would otherwise be landfilled, incinerated, or, at worst, become pollution,” Eisenberg says in an email to C&EN about the reports. What ultimately happens to the pyrolysis oil depends on what engineering assets the facility using the oil has, he says. “In several years we anticipate greater efficiencies as more research and innovation continue to optimize the process of converting pyoil into plastics,” he says.

There’s a narrative that pyrolysis and chemical recycling are the solution to the plastic pollution crisis, Singla says. “Turning plastics into fuel is not recycling. It doesn’t create new plastic. It removes materials from the production cycle by burning them,” she says. “When you do that, you have to extract more virgin resources to make new plastic.”

Yskamp argues that regulating pyrolysis as manufacturing instead of incineration is a way of rebranding so that people feel okay about continuing to buy plastic. Regulating pyrolysis plants as incinerators makes people think of burning plastic, he says. “Burning plastic doesn’t seem like a solution to the plastic problem, particularly for the communities around the facility,” Yskamp says.

Singla says the attention paid to how to regulate chemical recycling is taking away from what many advocates say is the real solution to the plastic pollution problem: stop making so much of it.

“Who wants a plastic knife, right? It can’t cut your steak,” she says. There are solutions on hand that are going to benefit the public and public health across the full life cycle of plastic, and the focus should be there, Singla says. “Recycling is an end-of-pipe solution. When we focus on recycling, we’re missing the opportunities to address this issue from the beginning to the end.”