WEST READING, Pa. (AP) — A Pennsylvania chocolate factory was fined more than $44,000 by the federal workplace safety agency on Thursday for failing to evacuate before a natural gas explosion that killed seven people.

R.M. Palmer Co. did not heed warnings from employees about a natural gas leak, according to the U.S. Occupational Safety and Health Administration, which issued multiple citations to the company.

“Seven workers will never return home because the R.M. Palmer Co. did not evacuate the facility after being told of a suspected gas leak,” OSHA Area Director Kevin T. Chambers, of the agency’s Harrisburg office, said in a written statement. “The company could have prevented this horrific tragedy by following required safety procedures.”

Palmer denied it violated any workplace safety standards and said it would contest the OSHA citations, which the company said are “legally and factually unsupported.”

The powerful natural gas explosion leveled one building and heavily damaged another at the Palmer factory complex in West Reading. Investigators have previously said they are looking at a pair of gas leaks as a possible cause of or contributor to the blast.

About 70 Palmer production workers and 35 office staff were working in two adjacent buildings at the time of the March 24 blast. Employees in both buildings told federal investigators they could smell gas before the explosion.

Workers at the plant have accused Palmer of ignoring warnings of a natural gas leak, saying the plant, in a small town 60 miles (96 kilometers) northwest of Philadelphia, should have been evacuated.