CRESSON, Texas – Officials say the search for a missing worker following an explosion at a Texas chemical plant has been halted while crews clean up chemicals that are leaching from the plant.

Hood County Fire Marshal Ray Wilson said Friday that about half of the 15,000-square-foot (1,400-square-meter) Tri-Chem Industries plant has caved in and remains on fire. The plant is in Cresson, 50 miles southwest of Dallas.

Friday afternoon, crews began clearing away burned and mangled metal, so the search could continue for an employee, missing since the Tri-Chem chemical plant exploded into flames Thursday morning.

On Thursday, family members identified the missing worker as 27-year-old Dylan Mitchell.

"This was a chemical facility that did blending of different chemicals to make specific products," said Hood County Fire Marshal Ray Wilson.

"I’m not sure exactly what chemicals they might’ve been blending at this time," Becker said.

With liquid chemicals on the ground and fires still burning inside the plant Friday, firefighters faced challenges as they tried to find Dylan Mitchell, a father from Weatherford. At one point Friday, they pulled out from searching because chemicals were leaching at the plant.

Wilson says they searched the front half of the building on Thursday and Friday and haven't found the missing worker, who is presumed dead. He didn't know when they would resume the search. The Texas Commission on Environmental Quality and the Hood County fire marshal's office haven't revealed what's in the plant's chemical inventory. Wilson said the plant contains acids that react to heat, pressure and water, which is why they haven't yet turned on the fire hose.

Although there is a fertilizer plant adjacent to the Tri-Chem plant, Wilson said there's "no known threat to their facility."

Dylan's brother, Austin, waited outside the plant for news.

"He's been in my heart since hes been about seven years old," said family friend Sandy Sparger.

"There’s nothing I would rather have than to bring some closure to this family," said Cresson Fire Chief Ron Becker.

Becker was the first emergency responder on scene Thursday, minutes after the plant exploded and caught fire.

"It blew out the back door and part of the roof," said Jesse Bailey, who works next door. "We saw four or five people run out."

"From there on, it started smoking real bad and caught fire," he said. "Then started 'poom, poom, poom,' blowing up. You could hear drums going off in there."

State documents show some of the chemicals stored there can cause skin corrosion and serious eye damage and have "acute toxicity" listed as one of the health hazards.

Investigators have insisted there is no threat to the public right now as far as air quality goes. The wind helped, officials said.