A North Texas man and his family fear the worst after an explosion destroyed the chemical plant where he worked Thursday morning.

Mitchell Family

Dylan Mitchell, 27, is believed to have been inside the Tri-Chem Industries Plant, located along Texas 171 in the town of Cresson about 20 miles southwest of Fort Worth, Thursday when something sparked a fire and explosion that consumed the building.

Mitchell has been missing since the fire was first reported; two of his coworkers were found and have been hospitalized with injuries.

Mitchell's brother, Austin Mitchell, spoke with NBC 5 Thursday afternoon and said his family is fearing the worst since his brother hasn't been seen since the blast was reported.

"That my brother's dead; that no one can find him. I don’t blame anyone, like any of the responders, because it’s messy. It sucks. I feel hollow," Austin Mitchell said. "It's been this long, he's probably dead."

Austin Mitchell, whose 27-year-old brother Dillon is missing after the blast, spoke with NBC 5 Thursday and said his family was fearing the worst.

One person is missing and two people have been injured in an explosion and large fire at a chemical plant in Cresson, southwest of Fort Worth, Thursday morning, authorities say.

Two other people working at the facility were injured in the fire, including one person who was critically burned on his trunk and hands and flown about 50 miles to Parkland Memorial Hospital in Dallas. A second injured person, whose injuries were not as serious, was taken to Lake Granbury Medical Center.

NBC 5 has learned about 12 people work at the Cresson facility, which opened about a year ago. There were no other injuries reported and it's not immediately clear how many people were working at the facility Thursday.

First responders, including a number of volunteer fire departments from multiple jurisdictions, including a hazmat crew from the Fort Worth Fire Department, were called to the fire at about 9:45 a.m.

Witnesses reported hearing crackling followed by a pop and a "big kaboom" before "big fireballs" began shooting out of the building.

A North Texas man and his family fear the worst after an explosion destroyed the chemical plant where his brother worked Thursday morning. Fears of another blast amid the toxic chemicals prevented crews from battling the ensuing blaze, an official said.

Firefighters arrived to attack the fire but were then ordered to stand down over concerns about subsequent explosions and exposure to toxic fumes. The attack plan was then scrapped in favor of simply allowing the fire to burn itself out.

As the fire continued to collapse the metal building, secondary explosions were seen at about 11:15 a.m. By 1 p.m., most of the roof of the building had collapsed and the fire had burned down to only a few active areas.

Cresson Mayor/Fire Chief Bob Cornett told the Associated Press that investigators believe the fire could have started by a worker dragging his foot along the floor while chemicals were being mixed. In conversations with NBC 5, Cornett clarified the statement to say that while static electricity may have been the cause of the fire, they won't know exactly what sparked the fire and explosion until they've had time to investigate the scene after the fire is out. Cornett added that people working in the plant have special shoes designed to reduce or eliminate static discharge and that theory may not be valid.

Cornett said the earliest rescuers could begin searching for Dylan Mitchell was Friday morning, after the fire had extinguished itself and heavy excavation equipment could be brought to the site.

Jessica Gregg says her son-in-law was burned on his back and legs in an explosion at the chemical plant where he worked. She said he started at the plant just three weeks ago and that they didn't realize how dangerous the job could be.

Jessica Gregg identified the man flown to Parkland as Jason Speegle, her son-in-law, and said he started working at the facility only three weeks ago.

"We were told that this was a hazardous job when he started, but we didn’t understand that it was something that could lead to this," said Gregg, through tears. "My daughter is very upset. We just need prayers. Everybody needs to be praying for them."

Kale Nicodemus, who was standing near the plant when the first explosion erupted, described hearing a noise followed by several "big fireballs" that kept shooting out of the plant.

"Things were blowing out of the roof, like metal lids on buckets. Then, the fire," said Jesse Bailey, who was working next door. "It smells like sulfur."

Witnesses to the chemical plant explosion in Cresson, Texas, March 15, 2018, said they heard crackles and pops followed by a louder boom before big fireballs started erupting from the building.

With winds from the south to the north, smoke from the fire blew toward DFW, including Fort Worth and Weatherford. The Environmental Protection Agency and other authorities are monitoring air emissions.

The Texas Center on Environmental Quality said they are assisting first responders and coordinating with Hood County, EPA responders, and Fort Worth hazmat for response actions needed to address any discharges from the site and air monitoring. The TCEQ said they'll also monitor cleanup efforts. Additionally, the State Fire Marshal's Office has been asked to investigate the cause of the fire.

The chemical plant and a nearby lumber yard were evacuated; no other evacuations reported.

Tri-Chem Industries offers commercial chemical blending services for customers in Texas, Louisiana and the Gulf Coast region, according to its website. Cornett told The Associated Press that Tri-Chem Industries mixes chemicals that are primarily used by the oil and gas industry to drill disposal wells. He said he doesn't know how many of the chemicals stored at the plant were hazardous, but that "what was burnt and exploded was quite toxic."[[476965643,R]]

A spokesman for the TCEQ, the state agency responsible for coordinating the cleanup, declined to produce a list of the plant's on-site chemicals, telling an AP reporter to file a public information request. In recent years, Texas leaders have made it increasingly difficult for the public to find out about the chemicals manufactured and stored at such plants.

After a fertilizer plant explosion in the city of West, Texas, killed 15 people in 2013, Greg Abbott, who was then attorney general and is now governor, ruled that state agencies could withhold information about hazardous chemicals because of "ongoing terroristic activity."

NBC 5's Kevin Cokely, Brian Roth, Cody Lillich and Don Peritz, along with the Associated Press, contributed to this report. Check back and refresh this page for the latest update. As this story is developing, elements may change.