Huge explosion and fire rocks Texas chemical plant; at least one person killed A shelter-in-place order was issued for residents and schools of Crosby, Texas.

A massive explosion tore through a chemical plant in Crosby, Texas, Tuesday, killing at least one person, injuring two others and promoting a shelter-in-place order for the surrounding community as firefighters worked for hours to extinguish a fire there, officials said.

The explosion occurred at the sprawling KMCO plant just after 11 a.m., sending a large plume of smoke over the area, about 9 miles east of Houston.

One person was killed in the blast, according to the Harris County Sheriff's Office.

Two people believed to be workers at the chemical plant were taken by emergency helicopter to local hospitals. Their conditions were not immediately released.

The Harris County Fire Marshals Office initially said one person was unaccounted for. It was not clear if that was the person who died.

"Our hearts and prayers go out to the individuals involved, as well as our first responders, employees, and our community," John Foley, the company's president, said in a statement. "The wellbeing of our people, neighbors and the environment remain our top priorities."

The blast shook homes in the neighboring area and a woman a mile from the plant was knocked to the ground, according to ABC station KTRK. People 20 miles away reported feeling the explosion, the station reported.

Harris County Sheriff Ed Gonzalez issued an order for schools and homes within a mile to shelter in place.

Gonzalez tweeted that a preliminary investigation indicates a fire started in a transfer line to a tank containing a colorless, flammable gas called isobutylene. He said the blaze then spread to a storage building.

There was no immediate word on what other chemicals were burning, but the plant primarily manufactures antifreeze products, according to KTRK.

Workers at the plant said they were warned of a leak and were ordered to evacuate just moments before a series of explosions erupted followed by the massive blast.

"Just run, that’s it," plant worker Randy Villalobos told KTRK. "It was scary. Very scary. Everybody that was around me was running."

Villalobos said he and about 20 other workers immediately ran to an exit gate only to find it locked.

"Everybody that was around me was running," Villalobos said. "We had to cross underneath a gate because the gate was locked at the time."