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10.19.2023 Legal News

EPA Plant Shutdown Appeal Heats Up

EPA is attempting to use the Clean Air Act (CAA) to immediately shut down a Louisiana manufacturer that is indisputably in compliance with the emissions limits in its state issued air permit. In its emergency request to a United States District Court, EPA alleges the emissions from the plant constitute an “imminent and substantial endangerment” under Section 303 of the CAA. In support of its case, EPA does not point to emissions above a final regulatory level, but rather uses risk levels set forth in its 2010 EPA Integrated Risk Information System (IRIS) Assessment for chloroprene.


The case deals with a facility located in St. John the Baptist Parish, Louisiana, Denka Performance Elastomer LLC, (Denka) that has been manufacturing neoprene since about 2008. In 2016, EPA and Denka each installed air monitors in the neighborhoods surrounding the facility to better understand the amount of chloroprene emissions exiting the fence line of the facility. In 2017, Denka entered into an Administrative Order on Consent (AOC) with the Louisiana Department of Environmental Quality (DEQ), whereby Denka agreed to and did in fact reduce chloroprene emissions through additional control devices.

In February of 2023, EPA sued Denka alleging air emissions of chloroprene from Denka’s operations present an imminent and substantial endangerment to public health and asking the court to preliminarily shut down the facility. EPA’s support for its claim of endangerment is that the average concentrations of airborne chloroprene near the facility have been consistently greater than EPA’s published IRIS assessment limit of 0.2 µg/m3 since at least 2016, based on two air monitors installed in 2016 near the facility. Specifically, the EPA’s 2010 IRIS Assessment establishes 0.2 µg/m3 as the average concentration of chloroprene that a person may breathe over a 70-year lifetime without being expected to exceed a 1-in-10,000 risk of contracting chloroprene-linked cancers.

In the meantime, in April of 2023, EPA issued a proposed rule setting National Emissions Standards for Hazardous Air Pollutants (NESHAPS) for the Group I & II Polymers and Resins Industry. Section 112(d)(2) of the CAA requires EPA to establish Maximum Achievable Control Technology (MACT) standards for listed categories of major sources of hazardous air pollutants (HAPs) and to revise them ‘‘as necessary” at least every eight years following promulgation. Section 112(f) of the CAA requires the EPA to assess the risk to public health remaining after the implementation of MACT emission standards promulgated under CAA Section 112(d)(2). If the standards for a source category do not provide ‘‘an ample margin of safety to protect public health,’’ the EPA must promulgate health-based standards for that source category to further reduce risk from HAP emissions. In the Proposed Rule published in April, EPA proposes to strengthen the emission standards for chloroprene “after considering the results of a risk assessment for the … Neoprene Production processes.” Specifically, EPA looked at the information gained from its published 2010 IRIS Inhalation Unit Risk Estimate (URE) for chloroprene and found that existing chloroprene emissions caps create an unacceptable residual cancer risk. Therefore, EPA proposed a substantial reduction in facility-wide emissions allowed per year and use of required new control systems. Denka submitted comments to the proposed rulemaking during the public comment period that ended in June of 2023.

In July, Denka filed a motion to dismiss the complaint, alleging EPA has no evidence to support its claim that chloroprene emissions from the facility present an imminent and substantial endangerment to public health because the emissions currently meet its permitted and regulatory limits. Other industry trade associations recently joined in the fight, filing briefs in support of Denka’s motion to dismiss the case entirely.

Section 303 of the Clean Air Act

Section 303 of the CAA gives EPA authority to bring an action in federal court for injunctive relief (e.g., shutting down a plant) to abate “imminent and substantial endangerments to public health, welfare, or the environment caused by emissions of air pollutants.” To bring such an action, the statute states EPA must be in “receipt of evidence that a pollution source” is presenting such an endangerment. The question thus becomes what Congress meant by “imminent and substantial endangerment” when it enacted Section 303. In its 1999 guidance on the use of Section 303, EPA states it interprets “endangerment” to mean “threatened or potential harm, as well as actual harm,” but recognizes that Congress stated during hearings on the law that it “intends that the authority of this section not be used where the risk of harm is completely speculative in nature or where the harm threatened is insubstantial.” Endangerment is “imminent” according to EPA when the risk of harm exists, but the harm may not occur for a period in the future, “if at all.” Finally, the endangerment is substantial where there is a “reasonable cause for concern that health or the environment is at risk.”

Here, the issue before the court is whether average exceedance of emissions above an IRIS risk level (rather than the regulatory emission level included in the facility’s permit) can serve as the basis for a finding of imminent and substantial endangerment. Denka argues the April 2023 Proposed Rule is the proper tool for EPA to use to bring the emissions at the facility down to a level that provides an acceptable risk to human health, and that rule is still going through the rulemaking process. Furthermore, Denka points out to the court that in the Proposed Rule, EPA has waived the statutory 90-day compliance deadline for emissions limits and control technology, giving Denka instead the statutory maximum compliance deadline allowed of two years after the rule becomes effective. Denka points out that EPA cannot give such a waiver unless it finds there is no imminent endangerment. Thus, Denka argues, EPA found no imminent endangerment with the current levels at the Denka facility when writing the Proposed Rule and is now contradicting itself.


While Denka is the only neoprene manufacturing facility in the United States, all manufacturers that emit air pollutants should be watching the Denka case closely. In fact, the American Chemistry Council, the United States Chamber of Commerce, the Louisiana Chemical Association, and the National Association of Manufacturers have filed briefs in the case due to their interest in whether IRIS levels can be used in an EPA enforcement action under Section 303. The case is just another example of the new ways EPA is using and plans to use multiple resources to reach a desired result, even where a facility complies with its current regulatory limits.  

United States of America v. Denka Performance Elastomer LLC and DuPont Specialty Products USA, LLC; C.A. No. 2:23-cv-735, U.S. Dist. Ct. E.D.LA (Feb. 28, 2023)

88 Fed. Reg. 25080 (Apr. 25, 2023)