the problem summarised

The current yearly production of rubber / elastomers is approximately 20 million tonnes. Nearly 40% of this is natural rubber, the remainder being mostly oil-based synthetic materials.

By far the largest application for these materials is in vehicle tyres. Over 1 billion tyres are manufactured annually using approximately 10 million tonnes of elastomer materials, including most of the natural rubber produced.

Once vulcanised elastomers have reached the end of their working lives they must be recycled or disposed of. It is estimated that between 750 million and 1 billion tyres are scrapped globally, weighing some 6 to 10 million tonnes. Approximately 550 million tyres weighing about 5.7 million tonnes are recorded as being scrapped annually in Europe and the United States of America alone.

Whilst tyres are often regarded as the primary target area for elastomer recycling, the waste from other products cannot be ignored, particularly the material scrapped during product manufacture (flashing, webbing, trim, etc).

Assuming that tyres form 60% of all rubber scrapped, then the global figure for rubber scrapped could be between 10 and 16 million tonnes.

Recycling rubber is not simply a case of melting the material down and reusing it, as can often be done with materials such as aluminium and glass. Reversing the vulcanisation process can be likened to returning a cooked pastry back into a reusable dough. Because of this difficulty, scrapped rubber, and in particular scrapped tyres, have traditionally been landfilled or stockpiled. The estimated quantity of stockpiled and landfilled tyres in the USA and Europe is in excess of 21 million tonnes with a further 2 to 3 million tonnes being added yearly.

The United Kingdom Environment Agency has reported a number of problems associated with the landfilling of tyres. If disposed of in large volumes, tyres in landfill sites can lead to fires. They also tend to rise to the surface, effecting long term settlement and possibly causing problems for future land use and reclamation. Tyres buried in landfill sites are a fire hazard and ignition can cause serious air pollution as well as the pollution of underground water supplies. A fire started in 1989 in a dump with 10 million tyres in Powys in Wales is still burning. The Environment Agency report also indicates that the effects of the long term leaching of organic chemicals are not known.

As a direct response to this problem, the European Landfill Directive bans the burying of whole tyres landfill sites and will include shredded rubber in 2006. The landfill site operators have also responded by dramatically increasing the disposal costs of tyres.

A number of organisations in Europe and in the USA are currently examining alternative approaches to dealing with waste rubber / elastomeric materials.

some statistics

Just a few of the many statistics published on, and by, the tyre and rubber industry. This list will be added to as more statistics become available.

6.5 million tyres were recalled by Bridgestone/Firestone in 2000

270 million -- number of scrap tyres generated in the U.S. in 1998

Approximately 290 million scrap tyres were generated in the US in 2003. (approximately 900 million globally)

500 million -- estimated number of scrap tyres currently in U.S. stockpiles

35 -- number of U.S. states that had banned whole tyres from landfills by 2000. Europe banned whole tyres from landfills in 2003 and tyre rubber in 2006.

59 -- number of tyre fires in the U.S. between 1996 and 1998

14 million -- number of tyres consumed in a 1990 tyre fire in Hagersville, Ontario, the largest tyre fire in history, which burned for 17 days and drove some 4,000 people from their homes.

75 -- percentage of recycled rubber in a retreaded tyre

100,000 -- number of barrels of oil that could be saved each day if Americans properly inflated their automobile

It takes five to eight years for a rubber tree to mature to the girth, at which it can be tapped and its economic life will then be 20 to 30 years.

Scrap tyres pose three environmental threats: they are an extremely difficult to extinguish fire hazard; they trap rainwater which can breed mosquitos that spread diseases; and they are bulky, virtually indestructible hazards that often work their way back up to the surface of landfills after burial.