Sinclair Refinery in Sinclair, Wyoming has agreed to pay a $378,000 penalty, update process equipment operating procedures, perform required training to workers, improve maintenance of equipment and perform integrity tests on pressure vessels and piping that will reduce the possibility of an accidental release of hazardous chemicals at the refinery.Hazardous substances of concern used at the refinery include large quantities of propane, butane, and flammable hydrocarbon mixtures. under the clean air act, facilities that utilize hazardous and flammable substances above specified thresholds must develop and submit a risk management plan to assist with emergency preparedness, chemical release prevention, and minimization of releases that occur. In June 2010, EPA inspectors found that the facility had not adequately implemented those regulations.