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AFFTON, Mo. – Residents are back home and streets around the Manor Chemical company plant are back open Thursday following a massive at the plant earlier that afternoon.

A large plume of smoke could be seen for miles. Firefighters and first responders evacuated people who lived within a half-mile of the facility, located in the 6900 block of Heege Road.

Neighbors reported hearing continuing explosions in the area.

Firefighters were staying back because of the dangerous situation. They got to the scene immediately but approached the scene at around 4 p.m. and set up a “hose perimeter” to help contain the extremely hot fire.

An expert in HAZMAT situations told FOX 2 that the firefighters’ presence on the scene now is a good sign. It means that the area is probably safe enough for them to work on. Firefighters likely know what is in chemical drums at the plant and where it is safe to go.

The Manor Chemical company started in 1972. They specialize in automotive, paint/coatings, labeling, printing, industrial manufacturing, and dry cleaning. They are a wholesale distributor and sell chemicals in drums that range up to 55 gallons.

It is not clear what was going up in smoke. The company distributes drums of their products but the amount and type of chemicals in the drums are not known at this time. Portions of a building, as well as plastic drums and other materials, are on fire.

The Red Cross is in the area to help people evacuated from the area.

Affton Fire Protection Chief Nick Fahs said Thursday night they believe the fire started because of an electrical spark. One firefighter was injured but he was taken to a local hospital and is okay.

Fahs said he has never had to battle a fire like this before.

“We could hear that tanker venting, that it was obviously heat pinging on it, it’s either going to crack open, melt, or explode, so when we heard that venting sound in an active fire situation it certainly put a panic in all of us and we needed to evacuate that neighborhood and from the chief’s point of view, we didn’t need any firefighters getting close to that,” Fahs said.

More than 100 firefighters from 13 fire department agencies, with about 62 trucks, helped battle the fire. It took about an hour and a half of active firefighting to get the fire under control.

Fahs said other agencies brought a drone to help battle the fire from above, which helped firefighters know which areas were safe to enter to battle the blaze. He said the three employees that were in the facility at the time of the fire and they were able to escape safely.

Fahs said the three employees helped the firefighters look through the drone video to tell them which chemicals were in each container as the blaze went through the facility.

The entire facility was destroyed.

He said Affton Fire Protection District doesn’t have a drone but this experience is making him want one for the district.

Fahs said he rode to the fire with his assistant chief.

“When we got in the car, he’s like, ‘This is always the facility that makes us nervous’ because there’s so many chemicals and when the doors went up, I could see a mushroom cloud about 450 feet in the air,” Fahs said.