When a midnight fire damaged the Bradley family’s home on Mill Road last month, Julien Bradley described the cause of the blaze as spontaneous combustion, linked to a pile of oily rags left inside the house by workers.
After the story appeared in the Press, some readers expressed surprise that a fire could start without any electrical spark or open flame to ignite it. But according to Fire Chief Rick Sicard, the state fire marshal’s office says spontaneous combustion has ignited more than 400 fires a year in Massachusetts over the past five years. While oily rags are a common cause, they are not the only one.
A chemical process
Spontaneous combustion begins with the chemical process of oxidation, which produces heat. Something that can burn—oily rags, damp hay, or soft coal, for example—begins to oxidize. If heat from the process escapes into the open air, all is well. But if the heat is trapped within a pile of rags or a haystack, the temperature can rise quickly and set the surrounding material afire.
Retired firefighter Warren Harrod and Peter Warren, Harvard’s former fire chief, both remember a fire that destroyed a house on Littleton Road about 10 years ago. That blaze also started with oily rags left from refinishing a floor. Because the house was not yet occupied, the fire was far along before it was spotted, Peter Warren recalled in a telephone interview.
The old rectory for Holy Trinity Catholic Church, which was across the street from the current rectory, also suffered damage from a fire that started with oily rags, the former fire chief said.
In 2012 Harvard firefighters helped to extinguish a blaze that destroyed a three-story building on Main Street in Ayer. The owner was turning the first floor into a restaurant, and he had just finished applying linseed oil to the new bar, according to Nick Laggis. Laggis, who owns the men’s clothing store next to the site of the fire, lost the entire stock of his store to smoke damage.
Even after they are laundered, sheets or towels with a residue of massage oil can catch fire inside a dryer, according to a website by West Bend Mutual Insurance. Chief Sicard confirmed that and added that he has also seen piles of bark mulch or wood chips combust spontaneously.
“It’s not an uncommon thing,” Peter Warren said of spontaneous combustion. He recalled at least one barn fire in Harvard that resulted from heat building up in damp hay. Such fires were not unusual, he said, “in the old days.”
‘Get them out of the house’
The first step in preventing a fire, Sicard said, is to check the label of any paint, stain, or cleaning product you use for warnings about spontaneous combustion. The right way to dispose of oily rags, he said, is to spread them flat outdoors and let them dry in the open air. Then put them in a tightly closed bucket filled with water.
Warren agreed wholeheartedly. “Get them out of the house!” he said. “If I even use turpentine, I leave the rags out in the open.”
