The Texas Commission on Environmental Quality is TCEQ is proposing to quadruple the acceptable threshold for exposure to ethylene oxide. Photo: Wikimedia Commons.

What is ethylene oxide?

November 11th, 2019

The Texas Commission on Environmental Quality is TCEQ is proposing to quadruple the acceptable threshold for exposure to ethylene oxide. Photo: Wikimedia Commons.

Ethylene oxide is a flammable, colorless gas used to sterilize medical equipment and make products like plastics, antifreeze, detergents and adhesives.

And, like benzene, it’s known to cause cancer. Breathing air contaminated with it can increase your risk of breast cancer and various lymphoid cancers.

The Environmental Protection Agency concluded in late 2016 that ethylene oxide is, in fact, at least 30 times more carcinogenic than previously understood.

But even short-term exposure can damage your eyes, skin, nose, throat, lungs, brain and neurological system. Children are especially at risk, because ethylene oxide can damage your DNA.

How does ethylene oxide affect our region?

Texas is home to at least 24 chemical and plastics manufacturers that release ethylene oxide into our air. Every year, they account for nearly half the entire country’s emissions, about 50 metric tons of it.

These industrial facilities inflict a staggering, disproportionate burden on communities of color and lower wealth. Twelve facilities are located right on the Ship Channel, including in Pasadena, La Porte and Channelview.

The impacts of long-term daily exposure to air pollution can go unaddressed in these communities because of limited financial resources and inadequate access to health care. These communities can also lack air monitoring that tracks their exposure to chemicals like ethylene oxide.

“Many families ... are dealing with generational cancer,” Harris County Commissioner Adrian Garcia, whose precinct includes Ship Channel communities, told the Houston Chronicle. “Children are being diagnosed with the same cancer the parents were diagnosed with.”

The most recent National Air Toxics Assessment shows there are more than 100 census tracts in Texas facing upper-bound cancer risk above the national average of 30-in-1 million. There are 15 tracts in at least three counties — Harris, Jefferson and Webb — facing an extreme, unacceptable risk above 100-in-1 million because of ethylene oxide.

“Ethylene oxide is of grave concern for Houstonians,” Houston Health Department Director Stephen L. Williams wrote to the Texas Commission on Environmental Quality (TCEQ) in September 2019. In one of our region’s highest-risk census tracts in La Porte, the cancer risk attributable to ethylene oxide is 312 cases per 1 million people, the Houston Chronicle reported.

What can we do about it?

Fully aware of these risks, though, TCEQ is proposing to quadruple the acceptable threshold for exposure to ethylene oxide — even though state law requires the agency to control air pollution to protect public health and welfare.

TCEQ says that ethylene oxide is much less potent than what the EPA concluded. That echoes claims by the American Chemistry Council, which represents companies that produce or use ethylene oxide.

In response, nine environmental groups, including Air Alliance Houston, Environment Texas, Environmental Integrity Project and Public Citizen, filed comments in September 2019 urging TCEQ to reconsider. “No one should have to get cancer just from breathing,” the groups wrote. “TCEQ must recognize the best available science ... instead of rubber-stamping industry attempts to undermine public health protections.”

But TCEQ isn't recognizing the best available science, using a scientifically flawed model that the American Chemistry Council lobbied for it to use, Chemical & Engineering News reported.

The difference is that TCEQ assumes that people in the worker study who had the lowest exposure to ethylene oxide represent the baseline for the entire population, Elena Craft, a toxicologist who is senior director of climate and health at Environmental Defense Fund, told C&EN. The EPA assumes that some people are not exposed to it, and those who aren’t represent the baseline.

Craft wrote in September 2019 that TCEQ’s “many problematic decisions result in a factor that ignores cancer incidence, breast cancer risk and increased risk from childhood exposures." That is convenient for companies who wish to ignore the effects of their pollution and try to avoid common-sense pollution control measures.

If TCEQ adopts the higher threshold, it could pave the way in Texas for the construction of new plants or expansion of existing facilities that make or use ethylene oxide.

It could also lead to a challenge of the EPA’s methodology, Craft said, since Michael Honeycutt, TCEQ’s top toxicologist, chairs the EPA’s Science Advisory Board. And Honeycutt has already fought EPA efforts to put stricter controls on pollutants like ozone and mercury.

As the Sierra Club’s Neil Carman told C&EN: “We don’t need more ethylene oxide pollution. We need less.”

Tresaugue is senior communications manager for the Environmental Defense Fund.


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