What happened

Operators opened valves and removed a flange on a pressurised Fuel Gas Mix Drum, releasing more than 23,000 pounds of flammable naphtha directly to the ground; more than 3,700 alarms in the preceding 12 hours had overwhelmed operators and delayed a shutdown. The resulting fire killed two brothers, Ben and Max Morrissey, and caused about $597 million in property damage — the deadliest incident at a US BP-operated refinery since Texas City in 2005. This was an accidental industrial incident, not an attack.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.