Denka Company



Denka is a chemical company headquartered in Tokyo, Japan. Founded in 1912 in Hokkaido, it is the world’s largest manufacturer of neoprene, which is used to make a variety of products such as adhesives, beer cozys, gaskets hoses and wetsuits. It also makes cement and plastics like styrene. The company’s most controversial asset is a neoprene factory named the Pontchartrain Works facility, built by Dupont in 1968 in the town of Reserve, Louisiana. The 2018 U.S. National Air Toxics Assessment found that cancer risks in St. John the Baptist parish were as high as 1,505-in-1 million, 50 times higher than the U.S. national average. In a one mile radius around the plant, the population is 94 percent Black. The company was forced to withdraw claims that U.S. government risk levels for chloroprene were 156 times too high after a peer-review of company research showed major flaws. Later it emerged that Dupont sold the plant in order after learning that the government was likely to impose strict controls on the plant.


 Basic chemicals, Agrochemicals, Petrochemicals, Pharmaceuticals, Construction materials


Offense Group: safety-related offense

Primary Offense: workplace safety or health violation

Level of Government: federal

Action Type: agency action

Agency: Occupational Safety & Health Administration

Number of Records
Total Penalties
$11,408 (October 12, 2021)
Individual Records & Summaries
Click here for violation data on Denka Company
Information in this section is drawn from the Violation Tracker database produced by the Corporate Research Project of Good Jobs First in Washington DC. It is the most comprehensive source of data on business violations of laws and regulations in the United States. For specific examples of misconduct, please click on the links.


Article Archive
Videos & Podcasts
Mary Hampton and other members of the Concerned Citizens of St. John the Baptist speak out against the pollution they are impacted by coming from the DuPont/Denka plant - Video by Julie Dermansky
Denka Performance Elastomer plant La Place, LA - Video by Julie Dermansky


Chemist Wilma Subra speaking about the DuPont Denka Plant in Cancer Alley - Video by Julie Dermansky


Protest at Denka AGM in Tokyo. June 19, 2020.
Taylor, Gerard and Nagra: "Cancer Rate Spike near Denka Chemical Plant in Louisiana"
New concerns about chloroprene emissions as EPA monitoring ends in Reserve


The Denka manufacturing plant in Reserve violated the Clean Air Act at least 50 times.



Recent & Ongoing Campaigns
Group calls for shut down of Denka plant in Reserve

1012 Industry Report | May 25, 2021

In a request filed last week, the Concerned Citizens of St. John urged the Inter-American Commission on Human Rights to investigate cancer risks, recommend air pollution limits and join the group’s calls to shut down the Denka Performance Elastomer plant in Reserve, reports

Amid global uprising for racial justice, Concerned Citizens of St. John renew demand for Denka Co. Ltd. to adhere to EPA guidelines for toxic chemical emissions in predominantly Black community

University Network for Human Rights | June 19, 2020

Denka’s neoprene facility in St. John Parish, Louisiana continues to emit dangerous levels of the carcinogen chloroprene, nearly five years after the U.S. Environmental Protection Agency (EPA) found that residents living near the Denka facility face the highest risk in the country of developing cancer from air pollution due to chloroprene emissions.

David v. Goliath: The October March to save lives in Louisiana’s ‘Death Alley’

The Rev. William Barnwell | The Lens | October 10, 2019

Rise St. James and the Concerned Citizens of St. John Parish can—along with many supporters—claim significant successes since our “Big March,” May 30th to June 3rd, 2019, in opposition of the petrochemical plants along the Mississippi from New Orleans to Baton Rouge.

The Big March to Save Lives in Death Alley

The Rev. William Barnwell | The Lens | July 29, 2019

In spite of the important coverage the Lens has given to the cancer-causing emissions of petrochemical plants in St. James and St. John Parishes, most Louisiana readers must learn what’s going on from the national press.

Residents of America’s Cancer Town confront chemical plant owner in Japan

Gavin Blair & Oliver Laughland | The Guardian | June 26, 2019

Residents of Reserve, Louisiana, have traveled to Tokyo to confront the executives and shareholders of a Japanese company which runs a chemical plant they say is responsible for a spike in cancers and a litany of other diseases in their home town – the town at the highest risk of cancer due to airborne toxicity ....

'They've been killing us for too long': Louisiana residents march in coalition against 'death alley'

Jamiles Lartey & Oliver Laughland | The Guardian | May 30, 2019

Demonstrators in Louisiana stepped off on a five-day march on Thursday, demanding environmental justice for a region besieged by toxic pollution from chemical plants.

Louisiana’s Cancer Alley Residents Sue Chemical Plant for Nearly 50 Years of Air Pollution

Julie Dermansky | DeSmog | July 27, 2017

If you drive along one of the main streets in Louisiana’s St. John the Baptist Parish, you may encounter a large sign warning about chloroprene in the air. These signs let people know that chemical emissions from the nearby DuPont facility, now owned by Denka, can greatly increase the risk of cancer for those who live around it. 

Major Investigations
& Lawsuits
State Plans To File Lawsuit Against Denka Chemical Plant

Travis Lux | WWNO Public Radio | June 19, 2019

Over the last few years, Denka Performance Elastomer, a chemical plant in St. John the Baptist Parish, has been in trouble with the EPA for potential emissions violations. Now, Louisiana’s Department of Environmental Quality is planning to file a lawsuit against the company.

Chemical companies at centre of Guardian's Cancer Town series face state legal action

Oliver Laughland & Jamiles Lartey | The Guardian | June 12, 2019

Louisiana’s environment agency is poised to sue the two chemical companies associated with America’s only neoprene plant in the town of Reserve, the Guardian has learned. The legal action relates to alleged violations of the Clean Air Act and Louisiana state environmental laws.

This amended lawsuit against LaPlace's Denka chemical plant is allowed back in federal court

Nick Reimann | Nola | May 1, 2019

A lawsuit to reduce or stop production at a LaPlace chemical plant will have another chance in front of a federal judge after being dismissed several weeks ago.

Environmental Impact
Inspectors Find Leaks Of Cancer-Linked Chemical At Louisiana Plant

Andy Szal | | June 29, 2017

Federal regulators suggested that a Louisiana chemical plant repeatedly violated clean air laws by emitting a likely carcinogen into the surrounding environment.

LaPlace chemical plant, criticized for releasing 'likely carcinogen,' cited for 50 potential Clean Air Act violations

Della Hassle | Nola | June 25, 2017

After sending investigators into the Denka Performance Elastomer plant for five days last year to find out why it was discharging troubling amounts of chloroprene into the air, the Environmental Protection Agency has found that the LaPlace chemical manufacturer potentially violated the Clean Air Act about 50 times, according to a report.


Corporate Headquarters
Nihonbashi Mitsui Tower, 1-1, Nihonbashi-Muromachi 2-chome, Chuo-ku, Tokyo 103-8338, Japan
Most Recent Gross Revenue
$3.368 billion (2021) | source
Most Recent Net Revenue
$0.216 billion (2021) | source

Note: List may not be complete.

Major Shareholders

Click here for the latest data.

Political Influence

Open Secrets - Tracks corporate lobbying of US politicians.


Open Secrets Logo Profile of Denka Co

Import & Export Data

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Subsidy Tracker
Subsidy Tracker
Subsidy Tracker is a project of Good Jobs First in Washington DC. It is the most comprehensive source of data on state and federal subsidies in the United States. For more details, click on the links.
Click here for details on subsidies received by Denka
Major Projects
Denka, owner of controversial LaPlace plant, asks regulators to OK higher emissions

Sara Sneath | Nola | March 13, 2020

Denka Performance Elastomer, the owner of a LaPlace plant that is the only one in America to produce the presumed carcinogen chloroprene, is asking the U.S. Environmental Protection Agency to increase the level of that compound deemed safe for public health.

Denka Announces Completion of Acquisition of DuPont's Chloroprene Rubber Business

PR Newswire | November 4, 2015

Denka Company Limited (hereinafter "Denka") announced on November 4 that on October 31, 2015, Denka Performance Elastomer LLC (hereinafter "DPE"), a joint venture Denka has established in the United States with Mitsui & Co., Ltd. (hereinafter "Mitsui"), completed procedures for the transfer ....

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