Industry sues US EPA over ethylene oxide rule

A battle over the cancer risks of ethylene oxide air emissions from chemical plants has landed in court.

The chemical maker Huntsman Petrochemical and two industry trade groups, the American Chemistry Council and the Louisiana Chemical Association, filed lawsuits on Feb. 21, challenging the US Environmental Protection Agency’s recent decision to maintain a 2020 regulation that limits ethylene oxide emissions from organic chemical manufacturing.

The 2020 regulation relies on a controversial 2016 hazard assessment conducted by the EPA’s Integrated Risk Information System (IRIS). The rule requires chemical manufacturers to reduce ethylene oxide emissions from equipment leaks, vents, and storage tanks to protect communities near industrial facilities.

Industry wants the EPA to use a less-protective risk assessment conducted by the Texas Commission on Environmental Quality (TCEQ).

In December, the EPA rejected the TCEQ’s assessment. The agency concluded that there is no scientific basis for changing its preference to use hazard assessments developed under IRIS. “The IRIS assessment continues to provide sound scientific conclusions that are consistent with the latest scientific knowledge,” the agency said.

The EPA also criticized the Texas determination for excluding scientific evidence that links ethylene oxide to an increased risk of breast cancer in women.

Ethylene oxide is a hazardous air pollutant emitted during the production of solvents, pesticides, and plastics. It is primarily used as an intermediate to make ethylene glycol. The carcinogenic gas is also widely used to sterilize medical equipment. In the US, facilities with the largest ethylene oxide emissions are concentrated in Texas and Louisiana.

Environmental groups have been fighting for years to strengthen health protections for people living near industrial plants that emit ethylene oxide. Through litigation by such groups and communities affected by the pollution, the EPA was forced to update its regulations in 2020.

Those groups are now pushing the EPA to close a loophole that exempts facilities from controlling ethylene oxide emissions during events such as severe storms or loss of power. They also want the agency to require plants to monitor air pollution at their fencelines.