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Scrap Tire Recycling Processes have Come a Long Way
Industrial rubber recycling is almost as old as industrial rubber manufacturing itself.
In 1820, just a year after he started making raincoats with rubberized cloth, Charles Macintosh already needed more rubber than he could import. His research partner, Thomas Hancock, came up with a solution.
Hancock developed a machine to grind up scraps of rubber produced during the raincoat-making process. These shreds were then mashed into larger rubber blocks that could be fed back into the manufacturing process.
Hancock called his machine a masticator because it essentially chewed the rubber scraps into smaller bits, but it was more widely known as a “pickle.”
The days of easy rubber recycling, however, were short-lived.
Vulcanization — the process for weatherproofing rubber that made much of the modern rubber industry possible — also makes rubber recycling more difficult. Once it has been vulcanized, rubber cannot be melted back down and formed into a new product, because vulcanization essentially links all the molecules in a rubber product into one big molecule that will not flow apart so easily.
Recycling still made strong, short-term economic sense well into the 20th Century because rubber, natural or synthetic, was expensive. In 1910, an ounce of rubber cost the same as an ounce of silver. That’s one reason the average recycled content of all rubber products was over 50 percent well into the 20th Century.
By 1960, however, the recycled content of rubber products was down to an average of 20 percent as cheap oil imports and the increasing use of synthetic rubber brought manufacturing costs down. The development of steel-belted radial tires in the late 1960s would just about finish off the rubber recycling industry, as it made slicing and grinding tires for rubber prohibitively expensive. By 1995, only two percent of the rubber used by the tire and rubber industry was recycled material.
Wasting resources often makes sense from a short-term economic perspective, but also often carries long-term risks. Such proved to be the case as more and more tires ended up in landfills and illegal dumps around the state.
Even before the tire recycling business collapsed during the 1960s and early 1970s, scrap tires began accumulating in landfills, illegal dumps, vacant lots, abandoned buildings and roadsides around the nation.
The Rubber Manufacturers Association estimates that between two and three billion scrap tires are in landfills or are otherwise “stockpiled” across the United States. The Ohio EPA estimates that over 40 million scrap tires in large dumps around the state, with perhaps another 60 million more in roadside dumps, rural lots and warehouses around the state.
Even those that were dumped in sanitary landfills created environmental problems. Sometimes landfilled tires work their way back to the surface, causing expensive damage to liners and liquid collection systems and compromising their ability to keep landfill contaminants from mixing with local groundwater and surface water. Like most states, Ohio has banned the landfill disposal of whole tires.
Scrap tires illegally dumped in abandoned buildings and on the landscape present even greater public and environmental health risks.
Fires in large tire piles are hard, if not impossible, to extinguish. Some have taken months to burn out, producing heavy smoke and toxic liquid run-off that can foul local groundwater and surface water. Air, water and soil pollution can actually be made worse if water or foam is used to put out the fire, so some have been consciously left to burn out.
This hazard became undeniable in Ohio shortly after August 21, 1999, when arsonists torched one of Ohio’s largest tire piles — 26 million tires piled over 140 acres at the Kirby Tire Collection and Storage Facility in western Wyandot County.
The fire burned five days, sending up a black column of smoke that could be seen more than 60 miles away. Oil released from the burning tires ran into a nearby creek, killing thousands of fish in the Sandusky River system. State officials estimated that five million tires burned in the blaze. More than 250 firefighters from 21 fire departments battled the blaze, finally bringing it under control by dumping topsoil on it.
Even putting out the fire created environmental problems, according to the Ohio EPA. The 750 tons of topsoil dumped on the Kirby fire became contaminated with oils from the burning tires, according to an article in the July 11, 2003, issue of Solid Waste Report. Ohio is paying a clean-up firm $837,000 to remove the soil and to treat contaminated water.
If some good can be said to have come from the Kirby fire, it moved the Ohio Environmental Protection Agency (Ohio EPA) and the state legislature to accelerate efforts to clear out the state’s illegal tire dumps.
Since 1996, the state legislature had been levying a fee of 50 cents on each tire sold in the state. Most of the money raised by the fee was spent by the Ohio EPA on inspections, regulatory enforcement and clean-up efforts at scrap tire dump sites. Another $1 million went to a Department of Development grant program that helped Ohio schools purchase running track pavement made from recycled tires.
A year and a half after the Kirby fire, Ohio’s legislature doubled the fee. The $1 million-per-year grant program was transferred to the Division of Recycling and Litter Prevention for a program to help Ohio businesses conduct the research and purchase the equipment needed to integrate scrap tires into their production processes. The rest — now around $11 million a year — is focused on the clean-up process. The state’s goal is to have all its major tire piles cleared out by 2010, when the fee expires. By then, the state also hopes to have end-use markets for every newly scrapped tire generated in Ohio.