The Wyoming Department of Workforce Services (DWS) Occupational Safety and Health Administration (OSHA) has cited Salt Lake City-based Sinclair Oil for seven violations stemming from a September 2013 incident at the Sinclair Refinery in Sinclair, Wyoming. An OSHA inspection following the September 27, 2013 explosion and subsequent fire resulted in seven citations and proposed penalties totaling $201,000. No injuries occurred as a result of the incident.

Joan Evans, Director of the Wyoming Department of Workforce Services said, “the OSHA investigation revealed a variety of violations present that could have been prevented if the required internal inspections had been conducted and the necessary safety procedures had been followed.” Evens added that, "Sinclair has several health and safety related projects and improvements in process. We look forward to the long-term resolution of these issues.”

The OSHA investigation found that an explosion and subsequent fire occurred at Sinclair Refinery’s #4 Hydro-Desulphurization (4HDS) Unit within the Hydrocracker Complex on Friday, September 27, 2013, at 10:10 p.m. Hydrogen embrittlement of a carbon steel control valve in the 4HDS Unit caused a leak of hydrogen which ignited. Hydrogen embrittlement is the process by which various metals become fatigued, brittle and fracture following exposure to hydrogen. The source of ignition is unknown. As a result, the control valve had deteriorated from the inside-out and caused the leak and subsequent explosion.

Monetary penalties go entirely to the local school district where the violations occurred.