Used tires, with too much wear to be safe on vehicles or unrepairable
punctures, are among the largest & most problematic sources of waste, due to
the large volume produced & their durability. Municipal trash haulers will
usually not accept them. Most heavily populated areas contain specific dumps
where huge piles of literally millions of discarded tires are kept, often in a
constant state of legal antagonism with the municipal authorities. Although
tires themselves are not considered hazardous waste, these dumps sometimes catch
fire & may burn for months before they can finally be extinguished, creating
enormous volumes of toxic air pollution, oil, & heavy metals. Some such fires
have become Superfund cleanup sites.
Ironically, those same characteristics which make waste tires such a problem
also make them one of the most re-used waste materials, as the rubber is very
resilient & can be reused in other products; it also yields much energy when
burned under controlled conditions.
Retreadded or recapped tires used to be very common, particularly in the
trucking industry; the rubber tread of a tire would wear off long before the
carcass, consisting of the fabric plies, sidewalls, & beads, was no longer
usable, & therefore good carcasses were simply overlaid with another tread &
returned to service. Since the tread is attached in the same way as with a new
carcass, such a tire is as reliable as a new one; in fact usually more so, since
each individual used carcass is inspected, which is not the case when
constructing new tires. With the advances in tire technology leading to longer
tread life & the changes in the relative economics of raw materials & labor,
this is no longer economically advantageous for automobile tires.
While salvaged tires make cheap toys which can be used variously for pets,
animals in captivity or human children, e.g. the ubiquitous "tire swing", they
can also be deliberately torn apart to re-use the rubber. According to the US
Environmental Protection Agency, every year Americans discard approximately 290
million automobile & truck used tires. Since 1989, when only 10 percent of
scrap tires were recycled or reused, the United States significantly increased
its tire reclamation efforts to slightly more than 80 percent. In 2003, tire
reclamation looked like this:
130 million were used as fuel
56 million were recycled or used in civil engineering projects
27.5 million were recycled into other products or projects; for example, rubber
lumber, stall mats for horses, roof pads, sports mats, shower tiles, truck bed
mats, & commercial flooring
12 million were ground up & used in rubber-modified asphalt for roads &
athletic tracks
9 million were sent to other countries, where they are used to make retreads
In addition to the 290 million scrap tires, 16.5 million used tires in the US
are given new temporary life as retreads.
Because of safety issues, new tires must be manufactured primarily from virgin
rubber, however, with recycled rubber making up only 5 to 15 percent of the
finished product.
Furthermore tire strips are used as a severe instrument for punitive
flagellation, which leaves dark bruises.
Mulches made from old tires have become available on the market for individual
or industrial agricultural or horticultural use, either as loose pieces
mimicking shredded wood, or in sheets of such pieces loosely adhered, for use as
walkways, edging, tree rings, stepping stones. Both types of product are also
marketed as excellent ground material for playgrounds, being longer lasting &
more forgiving that the usual materials used, e.g. s&, gravel, or shredded
wood or bark. Although the materials are extremely resistant to environmental
breakdown & essentially last forever, the possibility of whether toxic agents,
especially heavy metals, do leach out & possibly contaminate soil,
particularly where food crops are grown, is currently under investigation.
