AUGUSTA, Maine  — A Maine company that severed an underground propane line that caused a deadly propane explosion was cited for violating the state’s Dig Safe law, but no criminal charges are warranted, officials said Friday.

The propane line was ruptured by a Manchester company that was installing safety posts in a parking lot about 5 feet from the building, officials said.

A 500-gallon propane tank was refilled three days before the blast, and the building manager evacuated the building and opened windows after noticing that there were propane fumes and that the tank was empty again, the state fire marshal’s office reported in its conclusions about the September propane blast.

The explosion happened when the building manager and firefighters returned to the building to look for the source of the propane leak.

The blast, which leveled the building, was so powerful it blew a vehicle across an intersection and damaged nearby homes, leaving many homeless. One firefighter was killed and a half-dozen others were injured. Also injured was the building’s maintenance manager, who remains hospitalized.

The company responsible for severing the propane line was installing posts in the parking lot to protect an exterior air conditioning unit, officials said.

Although propane lines aren’t expressly covered by Maine’s Dig Safe program, the Maine Public Utilities Commission cited the company, Techno Metal Posts, for failing to notify dig safe officials before the excavation.

Company officials didn’t immediately return a message from The Associated Press.

A bill introduced in the Maine Legislature would add language that specifically addresses underground gas lines.