The accident at DuPont’s facility, located east of Houston – Texas, USA, killed four workers and injured a fifth when methyl mercaptan, a toxic chemical used in the company’s insecticide and fungicide manufacturing process, was released.
On 11th November 2014, one worker was overwhelmed by methyl mercaptan and later died. The gas was unexpectedly released when a drain was opened on a vent line, according to OSHA. Three co-workers who attempted a rescue died before the leak was brought under control two hours later.
OSHA in May 2015 cited the company for 11 violations at the factory, including not training workers to use the building's ventilation system, and issued $99,000 in a fines.
Following a second inspection, OSHA found eight violations at the Texas plant and fined the company $273,000, citing an "indifference" to creating a safe workplace. The company didn't properly inspect equipment, implement operating procedures or an have equipment safety plan, according to OSHA documents.
"DuPont promotes itself as having a 'world-class safety' culture and even markets its safety expertise to other employers, but these four preventable workplace deaths and the very serious hazards we uncovered at this facility are evidence of a failed safety program," Dr. David Michaels, an OSHA assistant director, said in a statement.
During recent audits by OSHAs on Du Pont facilities, following were the ratings given and severe repercussions have come out of the ratings.
• PSI – failed to document and maintain design specifications and materials of construction for process piping (Serious)
• PHA – process hazard analysis did not address potential employee exposure to hazardous chemicals and temperatures resulting from the atmospheric discharge from pressure relief devices (Serious)
• RAGAGEP – did not document that atmospheric discharge piping from pressure relief devices relieved to safe location and complied with the ASME Boiler and Pressure Vessel Code, Section VIII (Serious)
• Operating Procedures – did not develop and implement written operating procedures for each operating phase (Serious)
• MI – did not establish and implement written procedures to maintain the on-going integrity of process equipment such as lined piping (Serious)
• MI – did not perform inspections and test on process piping (Willful)
• MI – inspection data did not include t-min/t-required and corrosion rate values as stipulated in RAGAGEP such as API 570 and DuPont Corporate MI procedures (Willful)
• MI- did not ensure that the frequency of inspections and tests of process vessels was consistent with applicable manufacturer’s recommendations and good engineering practices (Willful)
• MI – Did not perform inspections and tests on a specific process line (Repeat)
CSB brings out the below four major design issues as part of their investigation on this accident. CSB yet to release its complete investigation report. We can expect a detailed report with investigation video soon so as to know more details about this incident, its root causes and learnings.
• First: The process included several interconnections between the methyl mercaptan supply line and a chemical vent system, which allowed a toxic leak into an unexpected location, where workers were exposed with fatal consequences.
• Second: The chemical vent system - which was intended to safely remove harmful vapor from process vessels – had a design shortcoming that allowed liquid to accumulate inside. This liquid regularly caused pressure buildups in the vent. The liquid needed to be manually drained by operators to prevent safety issues from interconnected equipment, such as reactors.
• Third: The vent drain that operators had to use was open to the atmosphere, meaning that workers were exposed to whatever chemicals were drained from the vent system.
• Fourth: The building was designed in such a way that even had ventilation fans been working on the day of the accident, it would likely not have effectively protected workers from chemical exposure. And we found that those ventilation fans were not, in fact, working at the time of the accident.
“Now let me say that DuPont has long been regarded as one of the industry’s safety leaders. In fact, DuPont has been viewed as an industry leader in processing hazardous materials for most of the last two centuries. After the Bhopal tragedy in 1984, the DuPont La Porte facility changed its production of methyl isocyanate - or MIC - the same chemical involved in the Bhopal accident, to an inherently safer method so that the highly hazardous chemical was no longer stored in large quantities but was used as it was produced. Such action has contributed to DuPont’s reputation as a leading light in safety, its slogan is: “Zero” safety incidents. The company markets its safety programs to other in the chemical industry.
But we have found that not only DuPont, but the industry as a whole must do much better. Complex process-related accidents with tragic results are taking place across the country at companies of all sizes. This problem includes major corporations such as DuPont, not just smaller companies that some refer to as outliers. It is clear that the current process safety regulatory system is in need of reform, and that companies themselves must do more”. – comments by Rafael Moure-Eraso, Chairperson of the CSB.