WAXAHACHIE (CBSDFW.COM) – The cause of a major chemical fire in Waxahachie remains under investigation Tuesday and smoke can still be seen rising from the burned-out buildings.

State and federal agencies were still at the central Magnablend plant Tuesday, one day after black smoke was visible for miles across North Texas. The groups are checking the chemical list and talking with employees who may have witnessed what went wrong.

Scott Pendery, Magnablend CEO, said employees witnessed some type of spark while mixing chemicals Monday. “What I’m hearing In talking to folks is there was a spark which would lead to think it was an electrical issue. I can’t explain why or how that occurred.”

There is still no word on what caused the fire or which chemicals were in use when the facility caught fire

The company says that 80 percent of their business is in the oil and gasoline business which includes making products used in fracking.

The biggest concern is the water runoff, and getting that properly vacuumed up and tested.

But EPA tests so far have found no significant hazard in the air or water.

Pendery stresses his company hasn’t had any major issues in 33 years and they’re not backing down from responsibility.

“We’ve been a good steward and a good neighbor and a good employer here and I want everyone to understand that. We won’t waiver from that its tragic and truly an accident we’ll figure out exactly what caused it and remedy it.”

Cleanup at the facility could take quite a while because of all the chemicals and possibility of fires flaring up along the way.