DEER PARK, Texas (AP) — At least two workers at a Houston-area oil refinery were killed Thursday after hydrogen sulfide leaked at the plant, setting off urgent warnings for nearby residents to stay indoors before authorities later determined that the public was not in danger.
Nearly three dozen other people were either transported to hospitals or treated at the scene, Harris County Sheriff Ed Gonzalez said. Hours after the leak began, Gonzalez said the area was still unsafe for investigators to enter and that officials may not be able to get inside until Friday.
The plant is operated by Pemex, Mexico's state-owned oil company, and located in the suburb of Deer Park.
Gonzalez said that the gas release happened during work on a flange at the facility, which is part of a cluster of oil refineries and plants that makes Houston the nation's petrochemical heartland.
Pemex said in a statement that investigations were underway and that operations had been “proactively halted” at two units with the aim of mitigating the impact.
City officials issued a shelter-in-place order but lifted it hours later after air monitoring showed no risk to the surrounding community, Deer Park Mayor Jerry Mouton said. Hydrogen sulfide is a foul-smelling gas can be toxic at high levels.
“Other than the smell, we have not had any verifiable air monitoring to support that anything got outside the facility,” Mouton said.
Television news crews showed multiple ambulances and emergency vehicles at the scene. Gonzalez had originally posted on the social platform X that one person was transported to a hospital by helicopter, but officials later said at a news conference that no one was airlifted.
The leak caused the second shelter-in-place orders in Deer Park in the span of weeks. Last month, a pipeline fire that burned for four days forced surrounding neighborhoods to evacuate.
