The Wyoming Department of Workforce Services (DWS) (WY-OSHA) has cited a refinery for seven (7) violations stemming from a September 2013 incident. 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. WY-OSHA monetary penalties go entirely to the local school district where the violations occurred. The OSHA investigation found that an explosion and subsequent fire occurred in the #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. The following citations were issued by OSHA as a result of the September 27th incident: