Jul 15, 2004
CSB Releases Safety Bulletin Emphasizing Dangers of Working on Piping and Equipment That May Contain Flammable or Chemically Reactive Materials
Bulletin Follows Investigation into January 2004 Huntsman Petrochemical Explosion in Port Neches, Texas
Washington, DC, July 15, 2004 - The U.S. Chemical Safety and Hazard Investigation Board (CSB) today released a Safety Bulletin calling on chemical plant and refinery operators to exercise appropriate caution when performing work on piping and equipment that could contain hazardous materials.
The bulletin, set to be considered by the Board at a public meeting today, results from the CSB's investigation into a January 13, 2004, explosion and fire at the Huntsman Petrochemical facility in Port Neches, Texas, where two employees were seriously burned and significant damage occurred to nearby equipment. The explosion and fire occurred as workers attempted to purge a thousand-foot-long chemical process pipe in preparation for a cutting and welding operation.
Huntsman managers and workers were aware of the importance of completely removing hazardous material before cutting into the piping, and relevant warnings were contained in the company's written operating procedures. In this incident, workers first purged the piping with nitrogen to force out residual chemicals, including a hazardous mixture of peroxide and alcohol that reacts violently when heated. But unknown to the workers, the piping included a 300-foot-long section that was three feet lower than the rest of the piping, and despite the nitrogen purge, a significant amount of the hazardous mixture remained trapped.
The next step in the operation was to use high-temperature steam to purge the piping of what workers believed would be a small amount of residual flammable hydrocarbon vapor. But the steam heated the peroxide that was trapped in the low section of piping. The peroxide then began to decompose, releasing heat and creating intense pressure. The pressure blew out a valve gasket and violently ruptured the pipe. Flammable vapors shot out of the openings and ignited into a large fireball, injuring plant workers.
After the accident, Huntsman found two drains in the low section of the pipe, which could have been used to remove the trapped liquid. Had Huntsman's procedures called for reviewing plant pipe drawings and physically walking the entire line within the work boundaries, the accident would likely have been avoided, CSB said.
CSB's Safety Bulletin points out that chemical plant and refinery operators routinely open piping to perform maintenance, change components, or reroute lines. The Bulletin states, "Safe work practices dictate the removal or mechanical isolation of hazardous material from piping and equipment before commencing work."
Under "Lessons Learned," the Bulletin notes that work involving the opening of chemical process pipes should never be considered routine. The Bulletin recommends that facilities should:
- Physically examine all piping and components between isolation devices such as valves, and be sure piping drawings are current
- Use the drawings to identify key components, such as low-point drains that can be used to remove dangerous chemicals
- Prepare a specific written procedure for removing hazardous material and consider the consequences of working on piping that is not completely purged.
CSB investigators conducted a three-day investigation of the January incident. Huntsman personnel also investigated the event and identified a number of corrective actions.
CSB is an independent federal agency charged with investigating industrial chemical accidents. The agency's board members are appointed by the president and confirmed by the Senate. CSB investigations look into all aspects of chemical accidents, including physical causes such as equipment failure as well as inadequacies in safety management systems.
The Board does not issue citations or fines but does make safety recommendations to plants, industry organizations, labor groups, and regulatory agencies such as OSHA and EPA. Further information about CSB is available from www.csb.gov. For more information, contact Sandy Gilmour (Public Affairs Contractor), 202-261-7614 or 202-251-5496 (cell), or Daniel Horowitz, 202-261-7613.