The refinery at a Pennsylvania zinc plant is still closed after a fatal workplace explosion that killed two workers. Investigators are still searching to find the cause of the blast.

The plant is in Monaca, 25 miles from Pittsburgh, where two men died of smoke inhalation after the explosion. The company and officials from the Occupational Safety and Health Administration are both looking into the cause of the accident. In an inspection that began in March, OSHA cited the company with 10 violations, two involved workplace noise problems.

Refinery explosions can seriously change the lives of all involved, our thoughts are with the friends and family of the victim.