U.S. Warns Of Acetylene Risk

The U.S. Chemical Safety & Hazard Investigation Board (CSB) is warning acetylene producers to take special precautions when handling acetylene, a highly explosive gas widely used as a fuel in welding and cutting metals.

The safety bulletin was issued by CSB on Jan. 26, one year after an explosion killed three workers and injured a fourth at the Acetylene Services Co. (ASCO) in Perth Amboy, N.J.

Investigators concluded that a combination of factors resulted in acetylene flowing backward from the company's production generator through water pipes and out of an open drain valve into a shed. The gas built up to a dangerous level and likely was ignited when it reached the hot surface of the shed's propane space heater, according to CSB.

Three workers shoveling snow near the shed—constructed of wood panels built around six recycled-water tanks—were killed in the powerful blast, and a fourth worker was seriously injured.

"The tragic accident at ASCO points to how important it is to have comprehensive operating procedures, to train workers in those procedures, and to have effective measures in place to prevent the backflow of flammable gases," says CSB member Gary L. Visscher.

"CSB is urging acetylene producers and handlers to review the safety bulletin and examine their systems and safety procedures to prevent this kind of accident from occurring again," Visscher says.

The bulletin urges operators to maintain up-to-date operating procedures; use checklists; relocate vents to safe, outside locations; test critical valves; and ensure that enclosures, such as sheds that contain hazardous materials, meet national fire code standards.

CSB recommended that ASCO implement an effective process safety management program and include written checklists that are understood by workers.