How Refinery and Plant Fires Happen: What Investigators Look At
These fires usually begin where a fuel meets an ignition source: flammable liquid or gas escapes, or was never fully cleared, and heat, a spark or hot equipment reaches it. Investigators tend to focus on four things: the ignition source, whether hot-work procedures and permits were followed, what was released and why, and the condition of fire-protection equipment. Explosions follow a related but different path and are discussed on the refinery explosion page.
Hot work is where the federal text is most specific, and it lays out a checklist that can later be compared with what actually happened. Under 29 C.F.R. § 1910.252(a), if the object being welded or cut cannot readily be moved, movable fire hazards nearby are to be taken to a safe place; if the hazards cannot all be removed, guards are to confine heat, sparks and slag; and if neither can be done, the welding or cutting is not to be performed. Before cutting or welding is permitted, the person responsible for authorizing it is to inspect the area and designate precautions, "preferably in the form of a written permit." Fire watchers are required in listed conditions, including appreciable combustible material closer than 35 feet to the work, and a fire watch is to be kept for at least a half hour after the work ends. The rule also bars cutting or welding in listed situations, including in the presence of explosive atmospheres, and bars hot work on used drums, tanks or other containers until they are cleaned so that no flammable materials remain, with connected lines disconnected or blanked. If you were on the crew, what you saw of the permit, the fire watch and the area before work began may matter.
The type of fuel matters too, because the federal definition reaches further than the word "flammable" suggests. Under 29 C.F.R. § 1910.106(a)(19), a liquid with a flashpoint at or below 199.4 °F (93 °C) counts as a flammable liquid, and the rule sorts these liquids into four categories by flashpoint and, for the most volatile, boiling point. Under the same paragraph, some liquids heated for use to within 30 °F of their flashpoint are to be handled under the requirements for a more hazardous category. For a family, this means the liquid at the center of a fire may fall under these rules even if no one on site thought of it as especially dangerous.
One agency that may look into a serious fire is the Chemical Safety Board. It describes itself as an independent, nonregulatory federal agency that investigates the facts, conditions, circumstances and cause or probable cause of accidental chemical releases resulting in a fatality, serious injury or substantial property damage. Its page says root causes are usually deficiencies in safety management systems, that it does not issue fines or citations, and that it makes safety recommendations. A board report describes what the board found; it does not by itself establish that any party was legally at fault.
The sequence of events is part of what any legal claim has to show. A worker or family may weigh asking which agencies, if any, have examined the fire, and an attorney can help sort out how those findings fit with the hot-work rules above.