A full investigation has begun into a chlorine release that occurred when the chemical was being transferred from a railcar to a tank truck at a facility in Glendale AZ in November. The Chemical Safety and Hazard Investigation Board (CSB) said it will begin a full investigation into the release that occurred at a DPC Enterprises facility near Phoenix November 17. The CSB completed another investigation earlier this year into a similar incident at a DPC Enterprises facility in Missouri in 2002.
The Arizona incident occurred when excess vapor in the transfer process was being vented to a scrubber, an environmental control device designed to prevent chlorine from escaping into the air. The scrubber failed to function properly and allowed chlorine gas to escape, according to CSB information. The release caused evacuations from the immediate area and close neighboring streets for hours. Authorities said 14 people, including 10 Glendale police officers, were treated for chlorine-related symptoms, including nausea, throat irritation, and headaches.
An initial investigation by CSB examined the offloading process at the chlorine repackaging plant, and interviewed workers, operators, and plant managers. Information has been gathered from local police and fire departments concerning community notification and emergency response. The CSB team has requested documents relevant to DPC’s process at Glendale, and will be consulting the Chlorine Institute (the industry’s main trade association) and other companies that manufacture or process chlorine on safety practices in chlorine handling. Testing will be performed on the emergency shutdown valves attached to the rail and tank trucks and on the equipment used in the scrubber system that is supposed to prevent overloading and warn operators of impending failure and the potential for a chlorine release.
The CSB completed an investigation May 1, 2003, on a massive chlorine leak at a DPC Enterprises facility south of St. Louis MO that occurred August 14, 2002. Saying that better equipment maintenance and quality assurance programs could have prevented the chlorine release at that time, the CSB called for industry-wide measures to improve chlorine safety, including ways to improve the use of analyses to confirm that hoses are made from the correct materials for use with chlorine.