At the end of 2003, the US generated approximately 290 million scrap tires. Historically, these scrap tires took up space in landfills or provided breeding grounds for mosquitoes and rodents when stockpiled or illegally dumped. Fortunately, markets now exist for 80.4% of these scrap tires-up from 17% in 1990. These marketsboth recycling and beneficial usecontinue to grow. The remaining scrap tires are still stockpiled or landfilled, however.
In 2003, markets for scrap tires were consuming 233 million, or 80.4%, of the 290 million annually generated scrap tires:
- 130 million (44.7%) are used as fuel
- 56 million (19.4%) are recycled or used in civil engineering projects
- 18 million (7.8%) are converted into ground rubber and recycled into products
- 12 million (4.3%) are converted into ground rubber and used in rubber-modified asphalt
- 9 million (3.1%) are exported*
- 6.5 million (2.0 %) are recycled into cut/stamped/punched products
- 3 million (1.7%) are used in agricultural and miscellaneous uses
Another 16.5 million scrap tires are retreaded. After any retreading has been performed, 290 million scrap tires are generated. About 27 million scrap tires (9.3%) are estimated to be disposed of in landfills or monofills. (Source: Rubber Manufacturers Association, 2004.)
*Many scrap tires are exported to foreign countries to be reused as retreads, especially in countries with growing populations of automobile drivers such as Japan and Mexico. According to Mexicos National Association of Tire Distributors, as many as 20% of tires sold in Mexico are imported as used tires from the US and then retreaded for reuse. Some foreign countries also import tires to be shredded and used as crumb rubber, or to be used as fuel. Unfortunately, not all exported tires are reused or recycled. The downside of exporting scrap tires is that the receiving countries may end up with a disproportionate amount of tires, in addition to their own internally-generated scrap tires.
Markets and Uses for Scrap Tires
Over 75% of scrap tires are recycled or are beneficially used for fuel or other applications.
Scrap tires are used in a number of applications. From 1990 through 2003, the total number of scrap tires going to market increased from 11 million (24.5%) of the 223 million generated to 233 million (80.4%) of the 290 million generated.
The three largest scrap tire markets are:
Many uses have been found for recycled tires including whole tires, tires chips, shredded tires, and ground rubber. Retreading also saves millions of scrap tires from being disposed of as scrap each year.
Even with all of the reuse and recycling efforts, almost one quarter of scrap tires end up in landfills each year. Landfilling scrap tires can cause problems due to their uneven settlement and tendency to rise to the surface, which can harm landfill covers. To minimize these problems, many states require chipping or grinding of tires prior to disposal. Sometimes scrap tires are also incorporated into the landfill itself as part of daily cover, or in a landfill cap.
In recent years, the placement of shredded scrap tires in monofillsa landfill, or portion of a landfill, that is dedicated to one type of materialhas become more common. Monofills may be used where no other markets are available and municipal solid waste landfills do not accept tires. Monofills are preferable to above ground storage of tires in piles, due to fire hazards and human health hazards.
State landfill regulations:
- 38 states ban whole tires from landfills.
- 35 states allow shredded tires to be placed in landfills.
- 11 states ban all tires from landfills.
- 17 states allow processed tires to be placed into monofills.
- 8 states have no restrictions on placing scrap tires in landfills.
Source: Rubber Manufacturers Association, 2003
Stockpiles and Illegal Dumping
In 1994, the estimated number of scrap tires in stockpiles in the US was 700 to 800 million. Since that time, millions of tires have been removed from stockpiles primarily due to aggressive cleanup through state scrap tire management programs. 275 million tires were estimated to be in stockpiles (Source: Rubber Manufacturers Association, 2004.)
- A tires physical structure, durability, and heat-retaining characteristics make these stockpiles a potential threat to human health and the environment. The curved shape of a tire allows rainwater to collect and creates an ideal habitat for rodents and mosquitoes.
- Prone to heat retention, tires in stockpiles also can ignite, creating tire fires that are difficult to extinguish and can burn for months, generating unhealthy smoke and toxic oils. Illegal tire dumping pollutes ravines, woods, deserts, and empty lots. For these reasons, most states have passed scrap tire regulations requiring proper management.
To help state and local governments reduce the economic burdens and environmental risks associated with scrap tire piles on their landscapes, US EPA Region 5 and Illinois EPA, with input from members of the national Scrap Tire Workgroup, have collaborated to create the Scrap Tire Cleanup Guidebook. The guidebook brings together the experience of dozens of professionals in one resource designed to provide state and local officials with the information needed to effectively clean up scrap tire piles. The guidebook discusses starting a cleanup program, working with contractors to clean up sites, and implementing prevention programs that will reduce scrap tire dumping.
To order, send an email to email@example.com and ask for publication #530-R-06-001.
Scrap tire piles are not treated as hazardous waste. However, once a tire fire occurs, tires break down into hazardous compounds including gases, heavy metals, and oil which may then trigger Superfund cleanup status.
Based on a survey of state agencies conducted by the Rubber Manufacturers Association in 2001, 91% of all scrap tires stockpiled in the US are concentrated in eleven states. For additional information, see the 2003 RMA study on scrap tire markets .
Tire piles/dumps can be found in big cities, small towns, and the countryside. Cleaning up these nuisance piles is time consuming and expensive. In an effort to limit dumping and stockpiling, most states have passed scrap tire regulations requiring proper management.
Many states have cleaned up large numbers of tire stockpiles. Minnesota, Wisconsin, and Maryland are three states which report having cleaned up all scrap tire stockpiles.
State and Local Governments
Scrap tires, as a solid waste, are regulated primarily by state governments. Currently, 48 states have laws or regulations specifically dealing with scrap tires. While each state has its own program, some common features include:
- Source of funding for the program;
- Licensing or registration requirements for scrap tire haulers, processors and some end users;
- Manifests for scrap tire shipments;
- Limitations on who may handle scrap tires;
- Financial assurance requirements for scrap tire handlers; and
- Market development activities.
Local municipalities help educate the public about illegal dumping and enforce anti-tire dumping laws. Local agencies are also usually responsible for tire pile cleanup.
Some local jurisdictions encourage proper disposal by allowing local citizens to drop off limited numbers of tires at recycling centers, or conduct tire amnesty days where any local citizen can bring a limited number of tires to a drop-off site free of charge. State scrap tire programs may provide financial help to fund such events.
Tire pileslegal or illegalpose two major health threats: pests and fire.