Process Puzzler: Avoid Another Fatal Accident

Readers consider the causes of a deadly fire.

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We’re in the midst of investigating a fatal accident caused by a fire that occurred at a petrochemical storage facility. A farmer living nearby reportedly smelled gasoline for several days before the accident. He says he called the refinery several times but wasn’t taken seriously. The Fluid Catalytic Unit (FCU) that produces much of the refinery gasoline was having an emergency turnaround during this period, so staff were stretched thin. They didn’t see much urgency because of the tank farm’s safety system, which relies on redundant controls with an automatic gauging system and high/high alarms on each tank. Finally, two operators drove out to the tank farm and died in the fire. How should we approach this investigation? Do you have any suggestions for improvements in the tank farm? What do you think killed the two operators?

Install LEL [lower explosive limit] detectors for organic vapors throughout the tank farm. These detectors would have allowed the operators to know of the condition of the atmosphere before entering the area. They also help detect leaks from valves, flanges and other equipment, besides tank overflows.

If the tank farm operators had been informed of the farmer’s concerns, they should have walked into the area, not driven. (So, perhaps the response procedures are not what they should have been or the dead operators ignored them.)
Ron Dettmann, chemical environmental engineer
SABIC Innovative Plastics, Ottawa, Ill.

In my view, the problem is not in the tank level but in the obnoxious vapor control vent system. A flammable gasoline concentration sufficient to ignite accumulated somewhere. It was set off from an ignition source, possibly from the vehicle that the operators who died were in or from static electricity. (One possible cause could be a stone thrown by the vehicle.) I suggest alarm ground monitor stations for hydrocarbons and activated carbon systems on the tank vents to capture fumes.

As for how to approach the investigation, I would look into the plant’s failure to respond to the farmer’s complaint, possible fuel spills in the area or tank leakage, weather conditions at the time of the incident, motivation to check the tank farm and the possible connection to the turnaround. I also would look at improvements to the plant emergency response program. Next, I would inspect the operator training records and review their procedures for handling flammable or explosive chemicals.
Robert Drucker, consultant
Northport, Ky.

If BP’s experience at Texas City teaches us anything it’s that there’s no win-win scenario. Once the Chemical Safety Board (CSB) finished their study it was clear that BP’s problems were systemic. I was working at the BP refinery in Whiting, Ind., while the Occupational Safety and Health Administration (OSHA) was settling on the fines for compliance errors found there — it was something more than $400,000. They’re on a long road to recovery.

Your only successful approach with accidents is to show good progress on resolving problems. Ideally, you should identify these problems, not wait for the CSB or OSHA. Don’t underestimate them! Do so at your own risk.

Try approaching the accident the way a lawyer would: run offense and defense. Define your strengths and weaknesses. Find out what the farmer knows, how often he has complained, and what his experience level is. If he has experience working at the refinery you could be in real trouble. Review the records. How does the refinery respond to these complaints and leaks in the tank farm? If it has a history of ignoring complaints OSHA will see that you pay.

While the accident is fresh, within the first day, draw a preliminary timeline for it. Plant politics can be a minefield, so be careful to sidestep anyone who won’t cooperate. Show people the hard evidence. Don’t be afraid to mention that you’re trying to head off or minimize an OSHA fine. Remind them, subtly, that their jobs are on the line. Talk to all shifts. Speak to contractors who worked at the FCU and the tank farm, even if they weren’t working the day of the accident or even involved in the turnaround. You may pick up some scuttlebutt that leads your investigation to some useful conclusions.
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