Hydrogen Sulfide is a highly toxic chemical compound that is found in a wide variety of oil processing operations. High concentrations of H2S may be present in crude oil, molten sulfur, tank and pit-bottom sludge and produced water, all of which may release H2S when agitated, heated, or depressurized. Typical operational activities where personnel may be exposed to H2S include drawing samples, handling and testing samples, gauging tanks, and when opening lines and equipment.
The Chemical Safety Board (CSB) conducts investigations into serious incidents that occur in the chemical and process industries. The following quotation is taken from the web site of the United States Chemical Safety Board.
The CSB is an independent federal agency charged with investigating industrial chemical accidents. Headquartered in Washington, DC, the agency's board members are appointed by the President and confirmed by the Senate.