The United States Consumer Product Safety Commission estimates that in 1998 clothes dryers were associated with 15,600 fires, resulting in 20 deaths and 370 injuries. Fires can occur when lint builds up in the dryer or in the exhaust duct. Lint can block the flow of air, cause excessive heat build-up, and result in a fire in some dryers. To help prevent fires, clean the dryer vent and exhaust duct periodically.