Marathon Petroleum Reports Hydrofluoric Acid Leak at Galveston Bay Refinery

Marathon Petroleum Corp's 585,000 barrel-per-day Galveston Bay Refinery in Texas City, Texas, on Tuesday issued a shelter-in-place notice because of a toxic leak, said people familiar with plant operations.

Marathon and Texas City officials ordered workers and nearby residents to go indoors and close windows for over an hour due to a leak of hydrofluoric acid (HF), said the people, who spoke to Reuters on the condition of anonymity. Hydrofluoric acid forms a ground-hugging cloud at room temperature that can lead to severe health problems and even death.

Two workers were taken to a nearby medical facility as a precaution due to a chemical leak at the plant, said Marathon spokesman Jamal Kheiry. He did not disclose the chemical involved.

"The Galveston Bay Refinery's automated response systems today activated mitigation measures in response to a small chemical release," Kheiry said in a statement. "The release has been stopped and air monitoring data indicate no off-site impact."

A Texas City spokeswoman said the city's fire department assisted Marathon with the incident for about an hour and a half beginning at 3:30 p.m. local time (2030 GMT).

The leak came from the 31,500-bpd alkylation unit 3, which uses hydrofluoric acid to convert refining by-products into octane-boosting components added to gasoline, the people familiar with the matter said.

The United Steelworkers union, which represents refinery workers, has sought to end the industry's use of extremely toxic HF because of the risks to workers and nearby residents of exposure.

Water cannons typically are used to spray HF vapor clouds during a release so the acid collects in puddles that can later be cleaned up.A police department spokesman in Texas City, which is 41 miles (66 km) south of Houston, said no injuries were reported from the leak.

(Reporting by Erwin Seba)