Two people are dead and at least 35 others were affected after a chemical leak involving hydrogen sulfide occurred at a PEMEX facility in Deer Park, officials said on Thursday.

The extent of injuries is unknown due to officials not being able to make entry into the affected unit, but at least one person was transported from the scene by Life Flight helicopter, officials said.

Deer Park Mayor Jerry Mouton gave reassurance to community members that there was not a chemical leak in the surrounding area, despite the smell of hydrogen sulfide seeping out into the air.

Harris County Sheriff Ed Gonzalez said the scene remains preliminary and fluid, but noted the "situation seems contained to the scene, and no threat to the external community."

In a statement to ABC News Thursday, PEMEX Deer Park said the gas release was reported at one of its operating units at 4:40 p.m. CDT.

The facility said members of its emergency response team, Channel Industrial Mutual Aid (CIMA) and Harris County Emergency Management personnel and other government agencies are on site and responding to the situation.

As officials assess the situation State Highway 225 has been temporarily closed, the facility said.

"Some members of the community may see flaring as we safely contain the situation," the facility said in the statement. "We are closely monitoring air quality and are not detecting any offsite impacts."

Officials from the city of Pasadena, Texas, said in a statement on X that the chemical released was hydrogen sulfide.

The PEMEX facility is a refinery that processes crude oil from several countries to produce gasoline, aviation fuel, diesel fuel and ship fuel.