NaHS, Piping Bulletins Issued by Safety Board

Safety bulletins concerning the removal of hazardous materials from chemical process piping and the proper handling of sodium hydrosulfide (NaHS) were released last week by the Chemical Safety & Hazard Investigation Board. The two bulletins grew from lessons learned during accident investigations by the independent federal board. The piping bulletin addresses the need to ensure that materials are completely purged from process piping before beginning any maintenance activities. The second bulletin examines accidents in which liquid sodium hydrosulfide is exposed to acid or heat and, as a result, large amounts of dangerous hydrogen sulfide gas are produced. The safety board notes that 32 workers have died and 176 have been injured since 1971 in NaHS-caused accidents. The safety board bulletins provide a breakdown of chemical use, past accidents, chemical characteristics, health hazards, proper and safe designs recommendations, and emergency response considerations. The bulletins are available at http://www.csb.gov.