On the whole (and when left whole), tires present few environmental problems. They are inert and pretty much boring when left alone. But the black tire that provides so much fun and freedom for us turns into a living nightmare when on fire - this is where the problems start.
In Saskatchewan, quite a few landfills still burn their refuse in order to reduce the volume of material in the active cell. Although an illegal action, burning is still happening. If a stockpile of scrap tires were to catch fire during this process, a variety of serious, long term problems could occur.
Getting a tire fire going is difficult (lightning has started tire fires) but once ignited, it burns very hot and is very hard to put out. The interior of a pile burns at temperatures in excess of 315°C.
Tires are made of rubber, fibre and steel. The rubber is a combination of natural rubber, petroleum products, chemicals and carbon black. These additives are necessary to improve the handling and wear of natural rubber. When tire piles burn, these chemicals emerge as two things: 1) oily residues that leach into the soil and 2) thick black smoke which contains large amounts of air pollutants. Tire fire emissions can pose significant health hazards to all involved (firefighters, residents, etc.) and include irritation of the skin, eyes, and mucous membranes, respiratory effects, central nervous system depression, and cancer. Long-term environmental and health effects are unknown.
Tires burn so well because of the amount of empty space in a whole tire (75%) and the doughnut shape of the tire. These attributes make a tire great for transport but make a burning tire very difficult to extinguish with water or to eliminate the air supply that fires feed upon.
The most famous tire fire happened in Hagersville, Ontario in 1990. It was the largest tire fire on the planet: fourteen million tires caught fire. It burned for 17 days and drove 4,000 people from their homes. Thirteen years after the fire, it is reported that the pile still smoulders - imagine the money being spent by that municipality and the province to keep it under control.....
The upside to this environmental nightmare is the new-found public awareness and education about the proper handling of scrap tires. The fire 13 years ago spurred the development of tire recycling programs that deal with (and have greatly reduced) the tire piles in many parts of the country.
Source: WasteWatch, October 2003