Contested chloroprene campaign continues for Denka, EPA

LAPLACE, La.—In the latest litigation surrounding the more than decade-long chloroprene emissions battle between Denka Performance Elastomer L.L.C. and the U.S. EPA, the Japanese chemical company is suing the EPA for "declaratory and injunctive relief."

The lawsuit, filed Jan. 11 in the U.S. District Court for the Eastern District of Louisiana, comes just weeks after the Dec. 22 "final order" and consent agreement issued by the U.S. EPA to Denka.

The consent agreement alleges that Denka "failed to make a hazardous waste determination" on the choloroprene emissions, and the ramifications contained within the consent agreement—including related waste management and disposal programs—are set to take effect Jan. 31, according to the consent agreement.

"In assessing the potential risks of chloroprene for the past roughly dozen years, EPA has often stressed the importance of considering and applying the best available science on risk assessment," Denka states in the Jan. 11 lawsuit. "However, in actually setting risk-based requirements for chloroprene, EPA has refused to consider what the agency admits is the best available scientific information.

"EPA's reason? The agency simply declares that it is not a priority and that it has no obligation to do so. EPA is wrong."

The U.S. EPA did not immediately respond to Rubber News' request for comment on the Jan. 11 lawsuit filed by Denka.

Denka goes on to claim that the emission toxicity of the chloroprene monomer—used in making neoprene for wetsuits, orthopedic braces and laptop sleeves, among other applications—has been vastly overestimated in past U.S. EPA on-site measurements.

While the U.S. EPA has used an IRIS, or integrated risk information system approach, to measuring chloroprene emissions, Denka is seeking a review of (and relief from) the U.S. EPA's methodology.

The EPA, Denka states, previously had accepted the application of an alternative "physiologically based pharmaco-kinetic" (PBPK) measurement model.

The latter model allegedly shows the relative level of health risk from chloroprene to be as much as 130 times lower than the IRIS assessment, according to Denka.

However, in a March 14, 2022, letter to Denka, the EPA rejected adoption of the PBPK model on the grounds that "there was no obligation to incorporate more recent science into the assessment."

And since its acquisition of the chloroprene rubber manufacturing business from DuPont in 2015, DPE said it has "consistently operated" in compliance with regulatory emissions standards.

DPE said it "regularly measures the concentration of substances in the atmosphere" around its plants and provides information on environmental measures to local residents and other stakeholders.

In addition, Denka said it has invested more than $35 million and introduced equipment at the plant along the east bank of the Mississippi River to reduce chloroprene monomer emissions by 85 percent, compared to 2014.

"EPA's repeated refusal to consider the best available scientific information on the potential risk of chloroprene is having real world consequences," Denka states in the recent lawsuit. "Worse still, EPA encouraged DPE to develop the latest available scientific information and, over a multi-year period, actively collaborated with DPE in ensuring that such scientific information was complete, accurate and up-to-date."

Denka calls the EPA's actions "politically driven."

"Why would EPA do this? Upon information and belief, EPA has taken this inconsistent position because EPA leadership is seeking to satisfy environmental activists and plaintiffs' lawyers who have brought multiple lawsuits based on outdated scientific information that dramatically overstates the risk of chloroprene," Denka states.

DPE goes on to say that it "strongly supports effective environmental protection for the facility's neighbors."

U.S. EPA Administrator Michael S. Regan is named in the lawsuit along with the federal organization, and is "being sued in his official capacity," Denka states.

Denka manufactures its polychloroprene rubber under the brand name neoprene, which was developed by DuPont in 1931.

Denka Performance Elastomer is a joint venture between Tokyo-based Denka Co. Ltd. (70 percent) and Mitsui Co. Ltd. (30 percent, also out of Tokyo), which acquired the neoprene production facility Nov. 1, 2015, from DuPont.

The company operates at the Pontchartrain Works Site in St. John the Baptist Parish, La., 560 Highway 44 in LaPlace.

There are about 42,500 residents in the parish.

Denka employs about 230 people at the facility, representing the second-largest private employer in the parish.

According to the U.S. EPA's Dec. 22 consent agreement, neoprene is manufactured in a multi-step process, involving a polymerization phase, during which chloroprene is mixed with water and other chemicals (such as viscosity modifiers and emulsification agents) to form an emulsion, known as neoprene.

The emulsion is then transferred to "poly kettle" reactors where a reaction creates the rubber in a batch polymerization process.

After adding stabilizers, the emulsion passes through a "poly kettle strainer" to remove undesired solids, or "poly kettle strainer waste."

The dry neoprene then is "processed into neoprene chips based on customer specifications," according to the U.S. EPA.

And it is precisely how this waste is managed, and its emissions are measured, that has the U.S. EPA and DPE at odds.

Chloroprene is a colorless liquid with an ether-like odor, and is on the Hazardous Substance List because it is regulated by OSHA and cited as hazardous by numerous federal agencies, including the EPA.

The Dec. 22 consent agreement filed by the U.S. EPA addresses and mandates remedies for Denka, though it remains unclear how the Jan. 11 lawsuit will affect the Jan. 31 start date for the mandates to take effect.

The EPA has classified chloroprene as a "likely carcinogen," a determination that was made in 2010.

Short-term chloroprene exposure can cause dizziness, increased heart rates, stomach disorders, hair loss and eye damage, according to the EPA.

Long-term exposure has been associated with increased risk of cancer and other health problems.

But Denka also has disputed that cancer cases have risen since the company took over from DuPont in 2015.

In fact, the two entities show the local cancer rates—as measured by the Louisiana Department of Environmental Quality and the Louisiana Tumor Registry—going in opposite directions.

Denka asserts that the LTR reports that "incidents of cancer are at or below statewide averages for cancers of potential concern."

This information is disputed by the EPA and the residents of St. John the Baptist Parish, who filed a civil rights complaint against the Louisiana Department of Environmental Quality on April 6, alleging that the LDEQ "discriminates on the basis of race in violation of Title VI of the Civil Rights Act of 1964."

About 60 percent of St. John residents are Black.

Regardless, the EPA does not appear to be moving off its measurements of chloroprene at the Denka plant in LaPlace.

"The EPA conducted on-site inspections of the facility in April and May 2022 and observed Denka's process of transferring 'poly kettle strainer waste' to an outside, open-air brine pit," the agency stated in a Dec. 28, 2022, press release accompanying the Dec. 22 consent agreement filing.

During this process, EPA inspectors say they documented elevated chloroprene concentrations in the air in the vicinity of the brine pit.

"Pursuant to the consent agreement, beginning Jan. 31, Denka will stop placing this waste stream in its open-air brine pit and instead meet hazardous waste regulatory requirements for both storage and ultimate disposal of the waste," the U.S. EPA states in the consent agreement.

Denka must consider EPA's "Environmental Justice Screening and Mapping Tool" when selecting disposal facilities and must consider using low-emission vehicles when transporting waste for disposal.

The company must further provide protective equipment to employees who handle "poly kettle strainer waste."

And terms of the consent agreement also require Denka to manage the waste as "hazardous" until a more robust sampling and hazardous waste determination effort can be completed by the company through a waste determination plan.

"By no later than Jan. 31, 2023, respondent must store the 'poly kettle strainer waste' when removed from the outside brine pit in containers that meet RCRA Subtitle C requirements," according to the consent agreement. "Such containers of (the waste products) must be placed in a spill berm or other secondary containment, and transported and disposed of in accordance with RCRA Subtitle C requirements.

"Denka will continue testing additional emissions reductions measures to reduce emissions from the management of this waste," the U.S. EPA states.

Remedies and modifications made by Denka will be subject to EPA review.

And the EPA reserves the right to assess a civil penalty of "not more than $25,000, and increased for inflation, per day of noncompliance for each violation."

One violation—"failure to make a hazardous waste determination"—is enumerated in the consent agreement.

"If successful, the emissions reduction projects alone have the potential to eliminate approximately two tons of chloroprene emissions per year from poly kettle strainer clean-out," according to Denka's Emissions Inventory, as reported to the U.S. EPA.

The U.S. Environmental Protection Agency in March 2022 rejected another request by Denka Performance Elastomer asking the EPA to revamp its 2010 assessment of chloroprene.

In its 2010 Integrated Risk Information System Toxicological Review of Chloroprene, the EPA determined that the chemical is "likely to be carcinogenic to humans" and that it has been found in levels (around DPE after 2015) much higher than 0.2 micrograms per cubic meter, the EPA's "inhalation unit risk" (IUR) benchmark for chloroprene.

This high concentration reportedly has been measured for several miles around the Denka facility, according to the EPA.

Denka filed the request for correction with the EPA July 15, 2021, its second attempt to weaken the EPA's assessment of the chemical.

"The materials submitted by Denka present new analyses and express views on how these products should be used in the risk assessment of chloroprene, but the Denka submission does not identify errors in the 2010 IRIS assessment," Maureen Gwinn, principal deputy administrator of the U.S. EPA, stated in a March 14, 2022, rejection letter (of the second RFC) to Denka. "After careful consideration, EPA has concluded that the underlying information and conclusions presented in the 2010 IRIS (review) ... and its supporting materials are consistent with EPA's Information Quality Guidelines.

"Hence, the RFC is denied."

Denka first disputed the EPA's characterization of chloroprene in a June 2017 RFC, saying the "unrealistically conservative estimate" may overstate the cancer risk for human chloroprene exposure by up to "two orders of magnitude," or about 130 times higher than where Denka believed the cancer risk should have been categorized.

Denka's initial RFC was rejected by the EPA in 2018 on the basis that Denka "had not presented sufficient new information developed since 2010 to justify the request."

The company argued that it attempted to do just that in its second request via a 2018-20 study, funded by Denka, assisted by the U.S. EPA and known as the Ramboll 2021 PBPK model.

This study was conducted by Hopewell, Va.-based Ramboll Environ and concluded in 2021.

Denka said this model for risk-based assessment uses more advanced methods for evaluating potential effects on human health.

Gwinn called the EPA's 2010 IRIS study "accurate, reliable, and unbiased" and claimed that it does, in fact, use the "best science available."

The high levels of chloroprene—reportedly recorded around the plant at 24.3 micrograms per cubic meter in January 2022 (about 120 times the 0.2 micrograms per cubic meter benchmark set by the EPA in 2010)—were first tabulated in 2011 when the plant was under DuPont as part of the EPA's National Air Toxics Assessment, according to the EPA.

While the 0.2 micrograms per cubic meter threshold has been established by the EPA, the IUR benchmark has not been used by the federal organization to set any actual rules, Denka told Rubber News last year.

Denka said in 2017 that the only ambient standard for IURs applicable to chloroprene is a Louisiana mark, an eight-hour benchmark of 857 micrograms per cubic meter.

Denka itself wrote that achieving the EPA threshold of 0.2 micrograms per cubic meter is not possible.

With high stakes for the country's only neoprene production plant as well as the residents of St. John the Baptist Parish, the fight over hazardous waste emissions continues into 2023, essentially the 13th year of the chloroprene emissions and classification dispute.