Safety First
The superintendent who covered for Dave had plenty on his plate, too. But his job was to do what the commanders at B-4 directed him to do, and on Monday afternoon he was told to babysit several additional jobs until Dave came back to work. “Just make sure all the jobs are secure and the subs see your face so we have a presence. No big deal,” was the wording used by Jeff.
By 5:00 Monday afternoon all the subs had locked up and gone. The covering superintendent arrived at the Hansen job at 5:40 and walked up to the front door. It was locked. Everything seemed OK. “It’s been a long day, and I left my jobsite keys in the truck … I don’t need to go inside. Everything looks fine,” he thought and left.
The reaction had started even before the painter and flooring subs left the job on that particular Monday. They didn’t know it, but a postgraduate science lesson had been set in motion. It was just a matter of gravity, time, and temperature.
The actual fire was estimated to have started between 1 a.m. and 2 a.m., according to the investigation team. By the time the call was placed to the fire department by a late-night police patrolman, 80 percent of the house was engulfed in flames. It took the fire department just under 10 minutes to reach the site and another two minutes to start pumping water onto the bonfire, but it was too late. The house was gone. Their mission now was to control the blaze to keep it from damaging neighboring properties.
Mop-up, as firemen call it, was still going on at 7:00 the next morning. No one at B-4 Builders had been contacted before that due to the fact that the office number was the only phone contact listed on the job sign out in front of the project. The principals of B-4 had unlisted numbers. No one was going to contact them at home during their private time. Several neighbors were awakened by all of the commotion on that early Tuesday morning and had told firemen on the scene that the home was unoccupied, but nearly complete.
What happened? The spontaneous combustion was caused by stain-soaked rags that were left in a plastic 5-gallon bucket. The painter or flooring sub had collected all of the rags from the day’s work and placed them in an open bucket, and left the pail and its contents inside the house.
Several rags were tossed on top of one another in that bucket, and the weight created friction on the lower layers of cloth, which caused the volatile elements of the stain solvents to heat up and smolder. Because the bucket had not been closed and airtight, an oxygen source was present, and the fumes ignited. The bucket quickly melted and spread the fire to the exposed wood floor sheathing. It also ignited recently stained and lacquered trim that was suspended on sawhorses directly near or above the bucket. The approximately 1,200 lineal feet of trim materials acted like kindling, causing the fire to escalate as concentrated heat, quickly consuming the dining room flat ceiling and within three to five minutes engulfing the entire roof structure in flames.
Dave was a neatnik, and if he had returned to the job that day he probably would have noticed the rags and the bucket and removed them to safety. He made it a habit to always clean up trash and never leave debris or containers inside the job at the end of the workday. Not one of the tradespersons on that project or in the B-4 organization knew about spontaneous combustion or its causes before this fateful occurrence. It’s simple, basic science that everyone in the building industry should know about and watch out for.
Any rags, paper towels, clothing, packing material, etc. that have been tainted by paint, stain, solvent, cleaners, or any kind of organic liquid should be considered susceptible to spontaneous combustion. Remember the grain elevator explosions in the early ’80s? Those were caused by grain dust, oxygen, and summer heat. The same thing can occur with airborne wood dust, shavings, and sawdust, especially in a warm environment. All job rags should be placed in a sealed metal bucket, soaked with water, and placed in a non-combustible area. Talk to your employees and subs about this at your next safety meeting.
