TCEQ officials monitoring air quality after plant ignited and injured worker in Shepherd, Texas

SHEPHERD, Texas (KTRK) -- Most roads were back open Thursday morning as air monitoring continued following a massive fire that injured one worker at a chemical plant in Shepherd, Texas.

Just 24 hours earlier, the fire sent thick, black plume of smoke into the air, forcing areas nearby to issue a shelter-in-place, with one school district electing to hold students.

It all started at about 8:17 a.m. Wednesday, when authorities said they received reports of a possible explosion at Sound Resource Solutions on FM 1127.

The fire raged for hours, but multiple fire agencies used foam to finally contain it by the afternoon, with crews putting out hotspots and remaining on-site through the night. Meanwhile, the Texas Commission on Environmental Quality said it would work with contractors on remediation and cleanup of the site.

TCEQ said the Bureau of Alcohol, Tobacco, Firearms and Explosives was at the plant on Thursday and completed itdon-site investigation.

Officials said they do not feel the fire was tied to anything criminal or set intentionally.

The agency said they have rapid assessment vans at the plant to monitor and isolate chemicals.

Darlene Pillows lives on the south side of the Sound Resource Solutions plant.

When the chemical plant went up in flames, her family begged her to evacuate because she suffered from breathing problems.

"At that time, we didn't know what chemicals, so it was later that we found how much chemicals that was in the air, and apparently, it was nothing that could harm," Pillows said.

She says she returned to her home Wednesday night and didn't notice anything off about the air.

Two retention ponds that took on most of the runoff from the fire are going to have to be drained as part of remediation. That could take days.

As of Thursday, officials' biggest concern is to ensure that all of the chemicals, foam, and ash stay contained to the property ahead of expected rain.

According to preliminary information, the employee was on the forklift when he noticed there were chemicals leaking from a container. When he reportedly went to lift the container, he noticed there was a fire and then an ignition. A full investigation into the incident is underway.

The man was first transported to an emergency room in Cleveland before being transported to the hospital, where he remains, to be treated for first, second, and third-degree burns to his arms, neck, and face.

The employee is said to be in his 20s and has only been employed with the company for about a week, according to the operations manager.

Officials clarified that of the nearly 40 people employed, only 19 employees were working at the time. All employees were said to be accounted for, and no other injuries were reported.

On Thursday, ABC13 returned to the site, where you could still see smoke.

Authorities said flammable liquids, diesel, turpentine, and other chemicals were involved in the fire. Some chemicals are reportedly known to be toxic.

Still, the TCEQ claims no chemicals have been found in the air out of the immediate site of the fire.

READ MORE: Diesel fuel, among several flammable liquids housed at chemical plant on fire in Shepherd, Texas

RELATED: What we know about plant at center of large fire in Shepherd, Texas

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