LDEQ records show frequent emergencies at Dow Plaquemine facility

Dow Chemical’s industrial complex in Plaquemine, three days after a fire and multiple explosions erupted at the plant on July 14, 2023. (Wes Muller/Louisiana Illuminator)

Dow Chemical’s plant in Iberville Parish has had 10 emergency incidents over the past four years that resulted in unauthorized releases of pollutants. Half occurred at the facility’s Glycol 2 unit where a recent explosion caused a fire that burned for nearly two days.

A review of Louisiana Department of Environmental Quality (LDEQ) records dating back to 2019 show most of the accidents involved power outages or valve failures.

In a Nov. 3, 2019 incident, a drum exploded at Dow’s Glycol 2 unit and released nearly 29 pounds of ethylene oxide — the same chemical involved in the July 14 explosion that sent a large mushroom cloud into the night sky and caused a fire to burn for nearly two days.

A preliminary state report noted that water sampling a day after the most recent explosion showed ethylene oxide levels at 39 parts per million (ppm) and then 0.1 ppm when retested at a different on-site laboratory. A LDEQ inspector provided no explanation for the discrepancy between results from the two labs in the report.

Ethylene oxide is used to make a broad range of consumer and industrial products, including detergents and disinfectants. It can cause cancer in humans and is highly volatile and reactive with many other compounds.

Hazardous chemical found in water after Dow plant explosion

Susan Buchanan, a professor of environmental health at the University of Illinois, said it’s possible the chemical evaporated during the time it took Dow to run the second test on the water samples. Buchanan researches the hazards of exposure to ethylene oxide and other toxic substances.

Ethylene oxide has come under scrutiny relatively recently as the U.S. Environmental Protection Agency lowered the amount that industrial facilities can release into the atmosphere. Research has shown there is virtually no amount of ethylene oxide emissions that are safe to people living nearby those facilities, Buchanan said.

“It’s really hard to get it low enough to where it’s safe to the people living nearby,” she said. “Any level can trigger one of the steps that can result in cancer. There’s no cutoff below where you’d say you’re completely safe from cancer.”

In Louisiana, the threshold at which facilities must report an unauthorized release of ethylene glycol to LDEQ is 10 pounds. All five accidents at Dow’s Glycol 2 unit resulted in unauthorized releases of the chemical.

On Nov. 6, 2022, the facility accidentally released 10,302 pounds of ethylene, 765 pounds of ethylene oxide and 11,774 pounds of methane into the atmosphere when the Glycol 2 unit lost power after a circuit breaker tripped. Air monitoring conducted at the facility’s fence line detected “no actionable readings.” The reportable quantities for ethylene and methane are 100 pounds and 1,000 pounds, respectively.

On June 10, 2020, Dow’s Glycol 2 unit lost power and released more than 26 pounds of ethylene oxide into the atmosphere over a 16-minute period. The amount far exceeded that allowed under Dow’s permit, which is 2.97 pounds per hour. LDEQ performed air monitoring at the facility’s fence line and detected nothing.

On Jan. 27, 2020, Dow’s Glycol 2 unit released 251 pounds of ethylene oxide after a worker mistakenly switched off an auxiliary pump. All air monitoring was “non-detect” for the incident, according to LDEQ’s incident report.

Since November, the Glycol 2 unit operated for several months with what appears to be a faulty alarm on a water scrubber, a control device that absorbs pollutants from a gas stream before the gas is vented to the atmosphere. In Dow’s semi-annual report to LDEQ, the company noted that daily emissions warning alarms were set incorrectly on one of its water scrubbers.

Other units at the Dow facility have also experienced emergency incidents.

On Dec. 28, 2022, Dow’s Polyethylene C unit released over 17,000 pounds or nearly 3,000 gallons of a liquid called Isopar E, a petroleum chemical used as a fuel and industrial solvent. A worker accidentally left open the bleed line on a storage tank, causing the chemical to leak into a containment area and vaporize for over two hours. The reportable quantity for Isopar E is 100 pounds.

On Jan. 16, 2021, Dow’s Polyethylene D unit accidentally released 6,388 pounds of ethylene into the atmosphere due to the electronic failure of an emergency vent valve within a reactor. The reportable quantity for ethylene is 100 pounds. Dow said it performed community air monitoring and detected nothing.

On Aug. 29, 2020, Dow’s Polyethylene A unit emitted 898 pounds of ethylene into the atmosphere after a pressure safety valve prematurely activated at a pressure below its threshold. Records of the incident do not indicate what might have triggered the valve.

On May 4, 2020, Dow’s Glycol 1 unit experienced a power trip that led to a control valve leak of liquid propylene chlorohydrin and hydrogen chloride from a 10-inch pipe. Both chemicals are toxic to humans. The release was contained in the plant’s holding pond. Crews were able to recover all of the propylene chlorohydrin, but approximately 9 pounds of hydrogen chloride vaporized into the atmosphere. The amount was below the LDEQ reportable threshold of 5,000 pounds.

On May 21, 2019, Dow’s Polyethylene B plant released 290 gallons of mineral oil after a pressure safety valve on a storage tank failed. The oil overflowed a concrete containment area and onto a concrete working area. The amount exceeded the reportable quantity of 42 gallons.

LDEQ spokesperson Gregory Langley said Dow is still conducting engineering analysis to determine what chemicals were released from the July 14 explosion and in what quantity. He referred additional questions to Dow, which has remained tight-lipped about the incident.

Dow operates under a federal consent decree in Louisiana and Texas that the company signed in January 2021 due to previous violations of the Clean Air Act. Under the settlement with the Environmental Protection Agency, Dow had to install and operate instruments and monitoring systems to ensure gasses sent to its flares are efficiently combusted. The company also must conduct air quality monitoring that is designed to detect the presence of benzene at the fence lines of the four covered plants and pay a civil penalty of $675,000 to LDEQ, according to a Justice Department press release.

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by Wesley Muller, Louisiana Illuminator July 27, 2023

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Wes Muller traces his journalism roots back to 1997 when, at age 13, he built and launched a hyper-local news website for his New Orleans neighborhood. In the years since then, he has freelanced for the Times-Picayune in New Orleans and worked on staff at the Sun Herald in Biloxi, WAFB-9News CBS in Baton Rouge, and the Enterprise-Journal in McComb, Mississippi.