The used tire is almost as iconic to rural Wyoming as the cowboy boot. It can be seen holding down trailer house roofs, serving as side bumpers on roadway cattle guards and inexplicably hanging alone on a barbed-wire fence.

Today, dozens of playgrounds are adorned with brightly painted industrial-sized tires challenging the athletic skills of climbing children. Massive haul-truck tires from coal mines are sliced in half to create sturdy stock watering tanks on the high plains of the Powder River Basin.

With ample access to industrial-sized tires in Wyoming, tire structures seem to have grown exponentially across the state. They appear in the forms of steel-belted windbreaks, random piles on the prairie and even what appears to be an entire horse arena made out of tires.

"We see they are an emerging issue in Wyoming. Obviously, the department is aware of it, and we're looking at how to address it," said Keith Guille, spokesman for the Wyoming Department of Environmental Quality.

The primary concern for illegal tire structures or rogue tire dumps is the possibility of fire, particularly if the tires are not clear of brush and tall grass. A tire fire is difficult to put out once ignited, and it spews toxic chemicals into the air and on the surface - a particular concern for stacks of tires near rural and urban residential areas.

Guille said DEQ will consider a statewide integrated management plan for waste tires, which will likely include meeting with public and private stakeholders to get a handle on how many waste tires are generated in the state and what happens to them.

"It's our vision to open this up to the public, gather some information from the public to see what the solution is," Guille said.

The effort is in addition to new standards issued by DEQ in July for scrap tire management.

The new standards underscored federal law that the generators of scrap tires - the mines, heavy equipment companies and retail tire businesses - are responsible for the proper management of their tires. If a mine's tires are discovered at an illegal dump, that mine is still liable for the cleanup of the tires.

In the new standards, DEQ also advised it would no longer approve tires for use in windbreaks, fences or other exposed applications.

As for fire concerns, local departments say they try to keep up to date on where big tire piles are located, and encourage landowners to take fire prevention measures.

"As long as people clear the grass away from them, I wouldn't see much of a concern," Gillette-Campbell County Fire Chief Don Huber said.

Scope and use

The industrial nature of Wyoming's economy requires a lot of large tires. It's estimated that Wyoming's 13 active surface coal mines in the Powder River Basin alone employ up to 500 haul trucks - not counting rubber-tire dozers, scrapers and other large, "off-road" rubber-footed vehicles - to produce more than 430 million tons of coal annually.

At that scale, the mining industry alone can generate more than 43 million pounds of tire waste each year.

Mines typically send their used tires to tire recyclers. But they also donate them to area ranchers who request them, and mines are also permitted to bury tires in their reclamation projects.

Rio Tinto Energy America, which owns and operates three mines in the Powder River Basin, said it sends its tires to a Wyoming recycling center.

Tires from Rio Tinto's Wyoming operations are either cut in half and made into stock watering tanks or shredded, crumbled and reprocessed into rubberized materials such as playground matting, Rio Tinto spokeswoman Heidi Hockett-Lowe said.

At the company's contractual insistence and cost, all tires that are stored for recycling are treated with mosquito larvicide to address West Nile virus considerations, because tires can collect water and become a breeding ground for mosquitoes.

"Our mine sites have also contributed tires to local ranchers at their request for use as livestock windbreaks," Hockett-Lowe said. "This has been done in the spirit of cooperation with our neighbors and to contribute to livestock winter survival rates."

For several years, Rio Tinto has made those free tires conditional upon the recipients following all related DEQ rules and guidelines.

Commercial uses

Envirotank in Campbell County is a state-permitted facility that handles industrial tires from some 21 different mines in the state, according to owner Michael Bulger. His company slices large haul truck tires in half to build stock water tanks and tanks used in the discharge of coal-bed methane water.

Bulger said sidewalls are also used for erosion control in the construction of ponds, and even as bumpers on docks for boats and ships.

"We're always looking for new uses for tires and ways of reduction," Bulger said.

Bulger said his company was able to work out a compromise with DEQ to drill holes in tires that are stacked - addressing concerns of tires collecting water and contributing to West Nile virus.

Although some people might think that stacks of tires for cattle windbreaks are a real eyesore, Bulger said the structures do help ranchers save their herds.

"If you've ever seen the amount of cattle that can get killed in wind and snowstorms, you'll see it's a usable tool out here," Bulger said.

Bob Doctor, program manager of DEQ's solid waste permitting and corrective action, said the agency's new guidelines not to allow windbreaks or fences serve two main purposes: to discourage waste and potential human health hazards, and to encourage better beneficial use of scrap tires.

Doctor said a good example of a better beneficial use was the Wyoming Department of Transportation's recent use of tire bales from Campbell County for fill and drainage under the South Pass highway.

"Those are the kinds of uses we're looking at," Doctor said. "We are promoting uses like this rather than fast and cheap uses like windbreaks on the prairie."

Contact energy reporter Dustin Bleizeffer at 307-577-6069 or dustin.bleizeffer@trib.com.