CSB calls on industry to improve chlorine hose safety
May 9, 2003 12:00 PM
The Chemical Safety Board (CSB) has called for better chlorine hose maintenance and quality assurance programs after investigating last year's accidental release of 48,000 pounds of the chemical at DPC Enterprises in the St Louis MO area.
The CSB recommended that DPC and its hose supplier, Branham Corporation, improve quality assurance programs, such as analyses to confirm that hoses are made from correct materials for use with specific products. The board also recommended that chlorine and hose-manufacturing companies develop a standard for positive identification of hoses.
The CSB investigation reported that DPC installed an unsuitable hose connecting a chlorine railcar to equipment at its Festus MO facility. The hose braiding was made from stainless steel instead of the recommended alloy, Hastelloy C, which looks identical but is resistant to chlorine. While investigators found that a supplier had furnished DPC with the improper hose, they said one cause of the accident was DPC's lack of an effective management systems to prevent such a hose from being placed in service.
Another root cause of the accident was the lack of an effective testing and inspection program for the chlorine emergency shutdown system at DPC, according to the investigation. Emergency shutdown valves failed to close properly once the chlorine leak had begun, greatly extending the duration and severity of the release. Investigators concluded that the valves were inoperable due to internal system corrosion, in turn caused by inadvertent introduction of moisture into the chlorine system. DPC's testing and inspection program was inadequate to uncover the faulty condition of the valves before the accident occurred and should be improved, the CSB said.
As a result of the August 14 incident, sixty-three people sought medical attention and some said they had various lingering affects as a result of the exposure to the chlorine, according to CSB information.
In its report, the CSB also recommended improvements to emergency response and community notification systems. The report found a lack of adequate planning and training for a major release, and noted that emergency breathing equipment stored at the plant became inaccessible once the leak had begun. Ultimately it took three hours for personnel in protective suits to reach the rail car and close manual valves to cut off the flow of chlorine, by which time more than half the contents of the tanker had been released.