The clean up of a hydrochloric acid leak that led to a nearly four-hour evacuation of homes and businesses on Monday in Weathersfield moved into its second day.

As the clean-up of nearly 2,400 gallons of the flammable and potentially explosive chemical continued, 21 News has learned that there is an on-going investigation by the EPA into what happened and who, if anyone, should be held responsible.

The leak was discovered just before 7:30 a.m. Monday morning.

Firefighters thought they were responding to a fire and quickly learned it was not smoke, but vapors from the chemical that were leaking from a tanker in back of Predator Trucking.

Captain Raymond Knepper said, "They had a couple of little hot spots that they had to dig up that still remained, but it's being treated and neutralized by the chemicals they need to neutralize it with, and it's going to be covered up with limestone gravel."

The Environmental Protection Agency responded to the scene and performed testing that showed there was no contamination beyond the containment area.

"Nothing got into the sewer systems or anything like that.  The EPA did a complete check of the entire area," said Captain Knepper.

A check of all local hospitals found that no one was treated for exposure in connection with the chemical leak.

However, the investigation is on-going into a faulty valve on the tanker owned by ProFrac out of Texas.  Whether further enforcement is needed or if the company will be cited could take a few weeks to determine according to the EPA.

So the question is does the oil and gas industry have to follow the same regulations as other commercial trucking companies?

Sergeant Barry Thompson, Southington Post of the Ohio State Highway Patrol is in charge of the Commercial Division, said, "They're regulated just like any other commercial motor vehicle would be when going down the highway, whether hauling hazardous materials or not."

ProFrac is conducting its own investigation, but not commenting on where the materials were headed, even though ODNR says the chemical is commonly used in the injection well process, and for oil and gas wells.

"Their tanks have periodic inspections which they must comply with which is set forth in the hazardous material regulations," Sgt. Thompson said.

A spokesperson for ProFrac says they are still trying to determine exactly what happened to cause the leak.