Noting the company started as a gunpowder manufacturer in 1802, and became a major chemical producer within 100 years, Dr. Moure-Eraso said, “DuPont has had a stated focus on accident prevention since its early days. Over the years, DuPont management worked to drive the injury rate down to zero through improved safety practices.”
Dr. Moure-Eraso continued, “DuPont became recognized across industry as a safety innovator and leader. We at the CSB were therefore quite surprised and alarmed to learn that the DuPont Belle plant had not just one but three accidents that occurred over a 33-hour period in January 2010.”
CSB board member and former chairman John Bresland noted the CSB finding that the phosgene hose that burst in front of a worker was supposed to be changed out at least once a month. But the hose that failed had been in service for seven months. Furthermore, the CSB found the type of hose involved in the accident was susceptible to corrosion from phosgene.
Team Lead Johnnie Banks said, “Documents obtained during the CSB investigation showed that as far back as 1987, DuPont officials realized the hazards of using braided stainless steel hoses lined with Teflon, or polytetrafluoroethylene (PTFE). An expert employed at DuPont recommended the use of hoses lined with Monel, a metal alloy used in corrosive applications. The DuPont official stated: ‘Admittedly, the Monel hose will cost more than its stainless counterpart. However, with proper construction and design so that stresses are minimized…useful life should be much greater than 3 months. Costs will be less in the long run and safety will also be improved.’”
In fact, the Monel hose was never used.
Internal DuPont documents released with the CSB report indicate that in the 1980’s, company officials considered increasing the safety of the area of the plant where phosgene is handled by enclosing the area and venting the enclosure through a scrubber system to destroy any toxic phosgene gas before it entered the atmosphere. The analysis concluded that an enclosure was the safest option for both workers and the public. However, the documents indicate the company was concerned with containing costs and decided not to make the safety improvements. A DuPont employee wrote in 1988, “It may be that in the present circumstances the business can afford $2 million for an enclosure; however, in the long run can we afford to take such action which has such a small impact on safety and yet sets a precedent for all highly toxic material activities.[sic]”
The need for an enclosure was reiterated in a 2004 process hazard analysis conducted by DuPont, but four extensions were granted by DuPont management between 2004 and 2009, and at the time of the January 2010 release, no safety enclosure or scrubber system had been constructed. CSB investigators concluded that an enclosure, scrubber system, and routine requirement for protective breathing equipment before personnel entered the enclosure would have prevented any personnel exposures or injuries.
The CSB investigation found common deficiencies in DuPont Belle plant safety management systems springing from all three accidents: maintenance and inspections, alarm recognition and management, accident investigation, emergency response and communications, and hazard recognition.
CSB Team Lead Banks said, “The CSB found that each incident was preceded by an event or multiple events that triggered internal incident investigations by DuPont, which then issued recommendations and corrective actions. But this activity was not sufficient to prevent the accidents from recurring.”
The CSB recommended that the DuPont Belle facility revise its near-miss reporting and investigation policy to emphasize anonymous participation by all employees so that minor problems can be addressed before they become serious. The CSB report also recommends the Belle plant ensure that its computer systems will provide effective scheduling of preventive maintenance to require, for example, that phosgene hoses get replaced on time.
For the DuPont Corporation, the Board recommended the company require all phosgene production and storage areas company-wide have secondary enclosures, mechanical ventilation systems, emergency phosgene scrubbers, and automated audible alarms, which are at a minimum consistent with the standards of the National Fire Protection Code 55 for highly toxic gases.
Industry groups have established various good practices for the safe handling of phosgene and other highly toxic materials in compressed gas cylinders. The report concluded that the most comprehensive guidelines are those set forth by the National Fire Protection Association, or NFPA.
The Board recommended that an industry group, the Compressed Gas Association (CGA) adopt the more stringent guidelines of NFPA Code 55 for the safe handling of phosgene and other highly toxic gases.
The American Chemistry Council (ACC), a prominent chemical industry trade association, was urged to revise its Phosgene Safe Practices Guidelines Manual. The Board recommended the manual advise against the use of hoses for phosgene transfer that are constructed of permeable cores and materials that are subject to corrosion by chlorides. And the ACC was urged to include guidance for the immediate reporting and investigation of all potential near-miss phosgene releases.
Chairman Moure-Eraso said, “Adoption of the CSB recommendations by OSHA, the Compressed Gas Association and the American Chemistry Council will greatly improve the safe handling of toxic gases nationally and will protect workers from deadly exposures.”
Public comments made on the draft report may be found at www.CSB.gov. Among the revisions made to the report as a result of comments were to better define thermal expansion in a phosgene hose; to note that phosgene operations were shut down permanently at the Belle plant after the accident; the timing of the oleum leak and the relative size of holes in the oleum piping; and that a Compressed Gas Association standard had been updated after, not before, the Belle plant phosgene accident; and the addition of a reference to EPA’s Chemical Accident Prevention Program and the fact that EPA, in addition to OSHA, has a requirement that companies initiate incident investigations within 48 hours.
The CSB is an independent federal agency charged with investigating serious 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 regulations, industry standards, and 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. Visit our website, www.csb.gov.
For more information, contact CSB Communications Director Hillary Cohen, 202-446-8094 (cell), or Sandy Gilmour, 202-251-5496 (cell).