Low levels of hazardous chemical went into Dow's outfall canals after explosion

A Google Earth image showing the stretch of Mississippi River between Dow’s outfall canal and Ascension Parish’s drinking water intake, a distance of about 30 river miles. (Image courtesy of Matt Rota/Healthy Gulf)

Water containing a hazardous compound from the Dow Chemical plant in Plaquemine flowed into the facility’s canals that lead to the Mississippi River after an explosion at the plant two weeks ago, though the company says testing indicates the water quality is normal.

Water sampling showed ethylene oxide was present in the surface water from fire suppression systems used to extinguish fires that burned for two nights, according to records from the Louisiana Department of Environmental Quality. To handle the large volume of water, Dow got a 14-day permit from the agency to reroute the used firefighting water directly into its outfall canals that lead to the Mississippi River, bypassing the facility’s on-site water treatment system.

“Our water management systems incorporate this practice,” Dow spokesperson Glynna Mayers said in an email. “Because a large volume of water from firefighting and fire suppression activities went to Dow’s internal water management system, the company initiated regular water sampling and analysis following the event. Our canal systems do intake and output water from the Mississippi River. Water sampling at internal checkpoints and at the final outfall at the river have indicated water quality is normal.”

By the time the contaminated water reached the outfall, it was so diluted that the chemical could no longer be detected, Mayers said in a phone call.

Dow’s outfall canal is roughly 30 river miles upriver from Ascension Parish utility system’s water intake, where the parish draws its tap water.

The July 14 explosion at Dow’s Glycol 2 unit caused a flaming mushroom cloud that illuminated the night sky and caused fires that burned until about 5 a.m. July 16. No injuries have been reported, and the company has not yet determined the cause of the accident.

The plant produces ethylene oxide, which is used to make a broad range of industrial products and to sterilize medical equipment. The state environmental quality agency classifies the compound as “extremely hazardous” as it can cause cancer in humans and is highly volatile and reactive with other compounds.

LDEQ records show frequent emergencies at Dow Plaquemine facility

An initial post-incident test of water sampling at an on-site lab showed levels of ethylene oxide at 39 parts per million (ppm) — a level that some consider dangerous to animals — though a second test showed a much lower concentration of the compound. The chemical doesn’t occur naturally in water.

Mayers said the first sample may have been inaccurate because it was tested on equipment not typically used for water samples.

A third sample analyzed at a third-party lab indicated ethylene oxide levels at 2.5 ppm. Dow reported this result to the state.

“All sample results were below federal and state water quality reportable standards,” Mayers said.

Scott Eustis, an ecologist with the environmental advocacy group Healthy Gulf, said it’s significant to see any amount of ethylene oxide in water sampling.

“From what I understand, it is highly unusual to find any ethylene oxide in water, and it’s not well studied,” Eustis said. “These readings are therefore likely to change on their own, and without more rigorous sampling, I would doubt if there is a way to tell if the reading was artificially high, or just high, and then decreased over time due to the volatility of the chemical.”

Most studies and information on ethylene oxide focus on the compound’s atmospheric effects, while relatively little is known about its impacts on aquatic environments. The American Chemistry Council, a trade association that represents Dow and other chemical giants, asserts that fish can survive in water with an ethylene oxide concentration of up to 41 ppm.

Eustis cited another study that indicated water contaminated with ethylene oxide at a concentration of 30 ppm caused chronic disease in cattle.

Dow sampled water every four hours as the fire burned and has collected and analyzed more than 140 water samples as of July 27, Mayers said.

Regardless of the water testing, both Dow and environmental groups have largely focused on the air quality following the incident.

“The July 14 event was primarily an air emissions event and air monitoring was consistently conducted on and around the Dow Plaquemine site,” Mayers said.

Ethylene oxide only got into the water when the firefighting system sprayed water to extinguish the long-lasting blaze. Dow has maintained that its air monitoring equipment has so far not detected any impacts to the community — a statement it has repeated many times since the eventand after previous incidents.

Eustis pointed out that Louisiana allows the companies that are responsible for the pollution to do their own environmental testing.

“It’s easy not to find stuff,” Eustis said. “I think what we see every time is we don’t have any context in the news. How often has this facility had these kinds of incidents?”

The Illuminator’s review of state records dating back to 2019 show that Dow Chemical’s plant in Iberville Parish has had 10 emergency incidents over the past four years that resulted in unauthorized releases of pollutants, mostly ethylene oxide. Half occurred at the facility’s Glycol 2 unit.

Ethylene oxide has only come under scrutiny relatively recently as the U.S. Environmental Protection Agency last year lowered the amount that sterilizing facilities can release into the atmosphere.

Some evidence has shown higher rates of miscarriages and breast cancer due to inhalation exposure to ethylene oxide. Other studies on animals noted damaging effects on reproductive organs such as decreased testicular weights and lower sperm concentrations, as well as cancers of the lymphoid, lung and brain, according to the EPA.

Eustis said the compound is likely more harmful than many realize and criticized Dow for not taking more precautions with the community surrounding the plant.

“We’re talking about a community that’s been chronically exposed for decades,” he said. “We should’ve seen at least a voluntary evacuation.”

Even if ethylene oxide is in the water, Eustis said the main known risk to people is still inhalation of the gas coming off the water.

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by Wesley Muller, Louisiana Illuminator August 2, 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.