Large barn fire in Virginia caused by spontaneous combustion, authorities say

Credit: Loudoun County Fire and Rescue Fire Marshal’s Office

A fire that destroyed a large barn in Loudoun County was caused by spontaneous combustion, according to fire officials.

The Loudoun County Fire and Rescue Fire Marshal’s Office (LCFR-FMO) said the fire was reported just before 4:30 p.m. on Tuesday at a barn located behind a house on Lincoln Road in Purcellville.

According to fire officials, crews arrived at the scene and found significant smoke and fire showing from the barn, which was approximately 40 feet by 80 feet big.

The fire was quickly extinguished, and no injuries were reported in the incident.

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Officials said the cost of the damages to the barn and its contents are estimated to be $532,000

According to fire investigators, the fire was caused by the spontaneous combustion of mulch and potting soil from a flowerbox.

"Spontaneous combustion can happen when a decomposing, organic material such as mulch generates enough heat to ignite without an outside source," said LCFR-FMO Chief Keith H. Johnson. "Because of this, a large or compacted area of mulch can create sufficient heat to spontaneously combust. Remember, in all cases, mulch fires are more likely to start when the weather is hot, and it has been dry for an extended period."

As a result of the fire, officials shared the following tips with residents and business about how to prevent mulch fires:

  • Maintain at least 18 inches of clearance between the edge of the mulch bed and combustible building materials, such as exterior vinyl siding and decks.
  • Keep landscaped mulch beds moist if possible. 
  • Recognize that hot and dry spells, along with windy conditions allow mulch fires to start more readily. 
  • Ensure proper clearance to electric devices, such as lights, by following the manufacturer’s instructions.
  • Use non-combustible materials such as river rock, pea gravel or crushed rock for the first 18" around the base of a building with combustible siding and around gas and electrical meters.
  • Consider using brick or non-combustible exterior siding when building or renovating a structure.
  • Use only approved receptacles to dispose of matches, cigarettes, and cigars such as sturdy metal or ceramic containers filled with sand, located away from the structure.  
  • Immediately report any smoke or fire by calling 9-1-1.    

Officials warn that fires that start in landscaping mulch or organic planting materials can spread quickly into shrubbery, up exterior walls and into a home or building.