According to the National Fire Protection Agency, the leading cause of dryer fires is the lack of regular maintenance. Clothes dryers account for the largest share of appliance fires. On average there are over 15,000 dryer fires throughout North America.
The most common sources of ignition in dryer fires are lint and household dust. They collect within the dryer cavity close to the dryer’s heating element, which can reach temperatures of 550F°. Forensic testing shows that cotton and wool clothing will ignite at temperatures of 250 F°. Therefore, a dryer fire is virtually imminent if lint from these clothing materials comes in contact with the dryer heating element. A controlled test conducted by Intertek Testing Services, showed that small lint fires regularly occur within the dryer cavity and may extinguish as the lint burns off. If there is substantial amount of lint within the dryer cavity a larger fire can occur and spread throughout the dryer and surrounding area.
A build-up of lint inside the dryer cavity and foreign matter in the duct such as birds nests and other debris can restrict the flow of dryer air. This can cause your dryer to not dry properly and efficiently, which increases the chance of overheating, mechanical failure and ultimately fire.