Kenneth Kandrac, CFI, Cause and Origin Expert
Case Synopsis: An investigation was conducted to determine the origin and cause of a fire, which was discovered on the exterior of an unattached garage positioned 8′ from the occupied dwelling. The 10’ x 18’ garage featured a gable roof and vinyl siding. There was an entry door on the left side and rear with a roll-up door fronting onto the driveway. The garage and property were enclosed by a 6-foot-high solid vinyl fence. The fire was reported during the late morning hours by a neighbor. Arriving fire personal found heavy fire at the rear side of the garage with extension to the interior.
The fire official and police detective determined that the origin of fire was at the left rear corner of the garage. Though the fire was of undetermined cause, they did theorize that leaves around the exterior had ignited. Initial conversations with the property owner revealed that he was not a smoker and had not been in the garage 3-4 days before the fire.
Expert Analysis: Evaluation of fire patterns on the rear wall of the garage showed low burns along the rear wall at ground level. After photographing all interior and exterior walls from several different angles, fire debris was systematically removed. Fire patterns along the rear wall and on a metal storm door clearly showed greater fire intensity at the right rear side extending to the storm door. As debris, such as a stack of metal-framed furniture, was removed, the remains of a five-gallon bucket were revealed. The remaining materials included what appeared to be a pellet fertilizer. The insured then recalled to investigators that a family friend had given him a pail of commercial fertilizer five or six years ago.
Many fertilizers contain varying amounts of Anhydrous Ammonia, Urea, and Ammonium Nitrate. These materials can be volatile and are hydroscopic. Anhydrous Ammonia must be stored in approved containers, kept in a cool, dry, well-ventilated location away from heat, direct sunlight, and hot surfaces. The rear of the garage faced south, and the integrity of the container was unknown; however, it had been exposed to repeated heating, cooling, freezing, condensation and rainwater.
Conclusion: Decomposition of the fertilizer was reported as the cause of the fire, which was subsequently determined to be accidental.Cause and Origin Expert | Kenneth Kandrac