2 dead after chemical release at LyondellBasell in La Porte, TX

Two people are confirmed dead in what La Porte officials are calling a "mass casualty" incident at a LyondellBasell chemical plant Tuesday night in unincorporated Harris County.

The La Porte Office of Emergency management confirmed LyondellBasell requested support around 7:30 p.m. Tuesday for an acetic acid leak at the company's 1515 Miller Cut Off Road facility, near the city.

Two people were killed, according to the company and the Harris County Fire Marshal's Office.

Five others were treated at the scene, and two others were hospitalized, according to Fire Marshal Laurie Christensen. The company had previously reported four people being transported for burn treatment in addition to the two dead.

Thirty-one additional people were being decontaminated and monitored for symptoms Tuesday night.

Christensen said that the cause of the incident — which she called a "chemical type explosion" release inside the plant — is still under investigation.

"Please keep the families of these victims and those that are injured in your prayers, the staff that are out here, and the first responders that are out here," Christensen said. "This is going to be a very long night. The investigation is just starting."

The conditions of the two hospitalized people was unknown as of Tuesday night.

Christensen identified the chemicals as methyl iodide, hydrogen iodide, and methyl acetate — a chemical acid used in food-grade vinegar that can cause severe burn, and is harmful if swallowed, toxic if inhaled, and harmful to the skin, she said.

Harris County Pollution Control arrived at the scene to conduct air monitoring, and there did not appear to be offsite impact, according to La Porte OEM.

The agency said the leak was "isolated," and no shelter in place or evacuation order was put into effect.