The series of three incidents began on Jan. 22, 2010, when an alarm sounded, leading operators to discover that 2,000 pounds of methyl chloride, a flammable gas, had been leaking unnoticed for 5 days. The next morning, workers discovered a leak in a pipe carrying oleum, producing a fuming cloud of the sulfur trioxide. The phosgene release occurred later that day, and the exposed worker died the next day in a hospital. Phosgene was used as a chemical weapon in World War I. A different type of hose, more costly than the one used at the facility, could have prevented the incident, according to the report. Better maintenance of the existing hoses might have prevented it as well.
CSB Chairman Rafael Moure-Eraso said the three incidents particularly concerned CSB personnel, given DuPont’s longstanding reputation for a commitment to safety. Noting the company started as a gunpowder manufacturer in 1802, and became a major chemical producer within 100 years, 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.”
Continued Moure-Eraso, “DuPont became recognized across industry as a safety innovator and leader. We at the CSB were therefore quite surprised and alarmed to learn that DuPont had not just one but three accidents that occurred over a 33-hour period in January 2010.
DuPont officials say they are reviewing the 172-page draft report. “Safety is a core value at DuPont and is our most important priority,” said DuPont spokesman Dave Hastings. Our goal is zero, meaning we believe all incidents and injuries are preventable. We are fully committed to being a good neighbor and operating our facilities safely and in full compliance with all safety, health and environmental requirements.”
Hastings said the company already has taken steps to improve safety at the facility based on its internal investigation of the 2010 incidents. These steps include:
- Performing an intensive operations safety review at each unit in addition to the normal safety processes and programs.
- Strengthening the process hazards review system to expand and improve employee participation.
- Improving maintenance and inspection system for hoses.
- Identifying and eliminating settings in the computerized maintenance system that could prevent maintenance work orders from being timely generated.
- Initiating a new system for alarm management.
According to the company, two of the processing units involved in the January 2010 incidents have been taken out of service over the past 18 months for business reasons. The Spent Acid Recovery (SAR) Unit has been permanently shut down and is being dismantled as part of a pre-existing business plan. The phosgene processing facility within the Small Lots Manufacturing (SLM) Unit has not operated since the January 2010 incidents, and all phosgene has been removed from the plant.
DuPont’s Belle facility occupies more than 700 acres along the Kanawha River, eight miles east of Charleston, the state capital. The plant produces a variety of specialty chemicals.
CSB: DuPont Knew About Safety Issues
Alarmingly, DuPont management appears to have known about safety hazards and shortcomings at the facility, based on information obtained by CSB during its investigation.
CSB Board Member John Bresland noted that the phosgene hose that burst in front of a worker, leading to his death, was supposed to be changed out at least once a month. The hose that failed had been in service for 7 months. The CSB investigation also found the type of hose involved in the accident was susceptible to corrosion from phosgene and that there were better, safer alternatives available.
Johnnie Banks, who led the CSB investigation team, said that documents obtained during the CSB investigation showed that as far back as 1987, DuPont officials realized the hazards of using the braided stainless steel hoses lined with Teflon, or PTFE. An expert employed at DuPont recommended the use of hoses lined with Monel, a strong metal alloy used in highly corrosive conditions.
Banks said 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.” DuPont, however, never switched over to the safer Monel hose.
Lives Saved Versus Cost of Improvements
Internal DuPont documents released with the CSB draft 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. However, the documents show the company calculated the benefit ratio of potential lives saved compared to the cost and decided not to make the safety improvements.
“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?” wrote an employee in 1988.
The need for an enclosure was reiterated in a 2004 process hazard analysis conducted by DuPont. DuPont management granted four extensions 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 management systems springing from all three accidents: Maintenance and inspections, alarm recognition and management, accident investigation, emergency response and communications and hazard recognition.
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, said Banks, who added, “But this activity was not sufficient to prevent the accidents from recurring.”
The report makes numerous safety recommendations. Among them, DuPont was urged to enclose all of its phosgene production and storage areas so that any releases of phosgene will be contained.
The CSB draft recommends that the DuPont Corporation 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 practices for the safe handling of phosgene and other highly toxic materials in compressed gas cylinders. The draft report concluded that the most comprehensive guidelines are those from the National Fire Protection Association (NFPA).
The draft report recommends that organizations such as the Compressed Gas Association (CGA) and the American Chemistry Council (ACC) adopt the more stringent guidelines of the NFPA for the safe handling of phosgene and other highly toxic gases.
The report also recommends that OSHA update its compressed gas safety standard to include modern safeguards – such as secondary enclosures for units using phosgene, mechanical ventilation systems, emergency phosgene scrubbers and automated audible alarms – for toxic gases such as phosgene.
“Adoption of the CSB recommendations by OSHA, the Compressed Gas Association and the American Chemistry Council would greatly increase the safe handling of toxic gases nationally, and will protect workers from the deadly exposures,” said Moure-Eraso.
The CSB draft report recommends 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, and that the Belle facility ensure that its computer systems will provide effective scheduling of preventive maintenance to require, for example, that phosgene hoses get replaced on time.
There is a 45-day comment period on the draft report that ends Aug. 22. Following a review of the comments and recommendations, the board will approve a final version of the report.
“These kinds of findings would cause us great concern in any chemical plant,” said Bresland, who is a one-time lab technician for DuPont. But they are particularly troubling at a DuPont facility “with its historically strong work and safety culture. In light of this, I would hope that DuPont officials are examining the safety culture company-wide.”