A landfill fire occurs when waste disposed of in a landfill ignites and spreads. In landfills that do not cover their waste with daily cover, biological decomposition creates substantial heat and can cause material in the landfills to spontaneously combust. In the U.S. 40% of landfill fires are attributed to arson.
Landfill fires are especially dangerous as they can emit dangerous fumes from the combustion of the wide range of materials contained within the landfill. Subsurface landfill fires also, unlike a typical fire, can not be put out with water. They are similar to coal seam fires and peat fires. Oxygen intrution control is the best method to prevent and fight subsurface landfill fires. "Fuel quenching", by allowing landfill gas build-up, can work well, especially in conjunction with maintenance of the daily cover of soil or material places on landfills.
Nearby streams can be threatened by leachate pools which may form if water is used to extinguish fires in landfills. There is also the danger that the landfill's membrane, a barrier placed under most modern landfills to prevent contamination of the underlying ground, will be destroyed or penetrated by the fire itself. Normally this liner prevents harmful liquids contained within the landfill from escaping into the groundwater and nearby streams. Destruction of the liner therefore leads to serious environmental problems.
Notable landfill fires
- On January 26, 1998, in Maalaea, Hawaii, a fire 15 to 20 feet underground. The fire was eventually deemed to be extinguished in a matter of weeks, with injections of more than 1,000 pounds of liquid carbon dioxide. It continued to smolder for 4 months.
- An underground landfill fire that was discovered in December 1996 in Danbury, Connecticut caused a strong odor like rotten eggs due to the high concentration of hydrogen sulfide. The fire lasted for weeks and the town was forced to install a gas recovery system, the cost of which exceeded $1 million.
- In early November 1999, at the Delta Shake and Shingle Landfill in North Delta, British Columbia. the fire burned between 20 and 30 metres (about 100 feet) deep. On November 27, Delta's Mayor declared a state of local emergency. Extinguishing the fire took slightly more than two months and cost more than $4 million (Canadian).
- On September 2, 2007 a large fire at the Fredericton Regional Landfill forced residents to stay indoors because of fears the smoke could be toxic.
^ “Ma’alaea Landfill Fire Sparks State Effort To Develop Guidelines,” Environment Hawai’i, Inc., Volume 9, Number 4, October 1998.
^ U.S. Fire Administration - Landfill Fires
^ T. Sperling, "Fighting a Landfill Fire", Waste Age magazine, Jan. 1, 2001