As a result, liquid naphtha quickly vaporized and formed a flammable cloud that rapidly ignited. The resulting massive flash fire killed two refinery employees, Ben and Max Morrissey, who were brothers.
In an effort to glean some useful knowledge out of an incredibly tragic event, the Chemical Safety and Hazard Investigation Board (CSB) released a safety video detailing what led up to the disaster. The video, entitled “Alarming Mistakes, Deadly Decisions: Fatal Fire at BP-Husky,” includes an animation of the events leading to the incident.
“This tragic incident unfolded over a period of 24 hours and during that time there were more than 3,700 alarms that sounded. There were many missed opportunities to prevent the fatal flash fire. Our investigation found that the operators did not recognized the serious danger unfolding around them or have the tools and safeguards to effectively manage the highly stressful abnormal situation indicated by the alarm flood,” said CSB Board Member Sylvia Johnson
Vapor Cloud Ignites
After the release on September 20, 2022, at 6:46 p.m., the flammable liquid formed a vapor cloud that reached a nearby ignition source resulting in a flash fire which killed Ben and Max Morrissey.
Contributing to the incident were the refinery’s failure to implement effective preventive safeguards for the overflow of towers and vessels in various pieces of equipment which led to an over-reliance on human intervention to prevent incidents; the refinery’s failure to implement a shutdown or hot circulation through the use of Stop Work Authority or otherwise; the refinery’s ineffective policies, procedures, and practices to avoid and control abnormal situations; the refinery’s alarm system which flooded operators with alarms throughout the day resulting in poor decision making; and the refinery’s failure to learn from previous incidents, according to a final report released by the CSB.
“BP could have implemented more effective preventive safeguards such as high-level interlock that could stop the flow of naphtha to the fuel gas mix drum. Such an interlock would have automatically stopped the liquid overflow event without the need for human intervention,” said William Steiner, CSB investigator in charge.
The video describes a series of cascading, and worsening, events that unfolded at the BP-Husky refinery on the day of the incident.
At 3:20 a.m. on September 20, 2022, a process upset in the refinery’s naphtha hydrotreater unit resulted in a loss of containment at the refinery.
Other Units Shut Down
This led to other refinery units being shut down, and eventually to decisions being made by BP personnel that led to liquid naphtha flowing into, and filling up the fuel gas mix drum, a pressurized vessel which normally contained only fuel gas vapor.
Board operator shown in CSB video making adjustments that helped lead to the fatal incident.
Source: CSB
As the fuel gas mix drum filled with liquid naphtha, the mix drum overflowed into vapor piping that led to downstream furnaces and boilers, which created the potential for furnace fires or explosions. Because of the increasingly abnormal state of the fuel gas mix drum, a board operator in the control room directed several BP to drain the liquid in the mix drum “as fast as you guys can.”
Shortly thereafter, two BP employees released the liquid to the ground by directly opening several valves on the mix drum.
The CSB’s investigation report concluded employees may have believed the liquid was an amine-water solution, not flammable naphtha. As the flammable naphtha released it vaporized and formed a large flammable vapor cloud.
At 6:46 pm, the flammable cloud reached a furnace in the Crude Unit 1 and ignited, resulting in an enormous flash fire that engulfed the two BP employees.
The video notes there was an “alarm flood” during the 12 hours preceding the flash fire. Between 6:50 a.m. and 6:49 p.m. on the day of the incident, board operators at the refinery were overwhelmed by 3,712 alarms, causing delays and errors in responding to critical alarms and communications among BP employees.
Leadership Meeting Results
Additionally, in mid-afternoon on the date of the incident, refinery leadership and process engineering personnel met to discuss the situation and plans for oncoming night shift support.
CSB video shows naphtha cloud reached a furnace in the Unit 1 area in which ignited the fatal fire.
Source: CSB
During the meeting, these personnel discussed shutting down Crude 1 operations or putting Crude 1 in “circulation” in an effort to stabilize Crude 1 Tower operations with the naphtha hydrotreater unit down and the Coker Gas Plant bypassed.
Ultimately, the group decided neither shutdown nor circulation would occur, which allowed the crude oil feed to continue.
Moreover, although one of the participants in the meeting summarized the meeting’s outcome in an email, the email was never sent, and there is no evidence the actions agreed upon in the meeting were ever otherwise conveyed to the night shift refinery coordinator or board operators, either verbally or in writing.
As in the CSB’s final report on the incident, the safety video covers four key safety issues that contributed to the incident:
- Liquid overflow prevention
- Abnormal situation management
- Alarm flood
- Learning from incidents
“The tragic loss of life underscores the importance of putting in place tools that employees need to perform tasks safely, such as stop work authority, and having adequate policies, procedures, and safeguards in place to effectively manage highly stressful abnormal situations,” Johnson said. “Doing so will help prevent a future needless tragedy.”
Click here to view the video.