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Public Radio's Environmental News Magazine (follow us on Google News)

Burning Rubber

Air Date: Week of

Not very many of the quarter-billion tires that Americans dispose of each year are recycled. As Nathan Johnson reports, many end up in huge piles in landfills where they easily catch fire, sometimes by accident and sometimes on purpose.


CURWOOD: Thanks to our passion for automobiles, Americans dispose of more than a quarter-billion tires every year. Some are recycled into rubber mats, or ground up and used to re-pave roads. And others end up scattered on roadsides or dumped in landfills. But a huge percentage of tires end up on fire. Some burn by accident. Others are incinerated on purpose. Nathan Johnson reports.

(Loud noises in an auto shop)

JOHNSON: The last time most drivers see or think about their old tires is when they turn them in, to buy new treads at places like Toscolito's in San Rafael, California.

(Noise continues)

JOHNSON: Here they'll take off your used tires for a buck and a quarter each, and then pay a middleman to haul them off. But every now and then, some of our old tires come back to haunt us.

REPORTER: Investigators say lightning struck a loading ramp early this morning and sparks touched off the tires. Firefighters say when they first arrived, heat shattered their windshield.

JOHNSON: Near Modesto, California, recently, a legal pile of 10 million tires caught on fire. Toxic smoke plumes shot up thousands of feet into the sky. Black soot landed on the windshields of cars 100 miles away.

(Flames crackle)

JOHNSON: Fires at tire dumps happen pretty frequently. In the last few years, Michigan, Pennsylvania, and New York all had massive fires. They can burn for months, even years. Tires end up in dumps because there's just not much of a market yet for used rubber. But millions of tires outside of dumps, tires that are legally disposed of, still end up being burned.

(A car door opens; bird song in the background)

JOHNSON: A few blocks from her home in Cupertino, California, Joyce Eden stops her car and points out some wisps of smoke rising from the Hanson cement plant about a mile away.

EDEN: It was only when some of the people in the community became aware of, that the cement plant had burned tires for fuel in a test burn and hadn't notified any of us about it, that I became concerned along with other people in the neighborhood.

JOHNSON: Ms. Eden says the cement company and local air officials promised neighbors that emissions from tire burning at the plant were safe. But she says concerned residents did their own research.

EDEN: Through the force of our knowledge, we were able to get their scientists to admit that, yes, the health risk did go up with burning tires for fuel.

JOHNSON: The Hanson cement plant stopped burning tires for fuel. But many factories and power plants around the country still do burn tires.

(Typing; a phone rings.)

SCHWARTZ: Hello, this is Sy Schwartz.

JOHNSON: Seymour Schwartz is a professor of environmental science at the University of California at Davis, who has compared the emissions from tire burning and coal burning.

SCHWARTZ: There were more than 100 percent increases, and in some cases more than 1,000 percent increases, in PAHs, the polycyclic aromatic hydrocarbons. And those are carcinogenic. There's no debate that there have been large increases in some types and categories of toxic pollutants. But there has been disagreement over the meaning, in terms of whether those increases create additional risk or not.

JOHNSON: Most regulators say there's no reason to worry, and some states actually promote burning as a way to get some value out of what's otherwise a problem. Meanwhile, as the debate over health hazards continues, there's a brisk business in tires as a cheap source of fuel.

(Auto body shop noise)

BURN: That is a state-of-the-art primary tire shredder. In fact, I just bought it last month.

JOHNSON: Michael Burn is president of Total Tire Recycling in Sacramento. It's the largest processor of scrap tires in northern California.

BURN: We bring them in here, we shred them, we chip them, we slice them and dice them, you know.

(Rubber grinding)

JOHNSON: The metal jaws of this shredder grind whole tires into little two-inch chips. Some of these chips are used in making road pavement and other products, but most of them are burned. They're a popular fuel in part because each tire contains the equivalent of seven gallons of oil.

BURN: A tire has more BTUs per ton than coal does. They're shipping in coal, I believe, from Colorado, Utah, and are paying upwards of $40 a ton to ship it here. Well, I can provide them with a ton of tire chips at $10 to $20 a ton, so the cost is half of what they would pay and gives more energy than they get from the coal.

JOHNSON: Environmentalists want government to cut down on incineration and do more to jump-start new markets for used tires. But tires are hard to recycle because the rubber has gone through a process called vulcanization, to give them extra strength.

SERUMGARD: Now what vulcanization does is mixes rubber with other chemicals, principally sulfur, and then subjects that resulting compound to heat and pressure. It's not unlike baking a cake.

JOHNSON: John Serumgard of the Rubber Manufacturers Association says just as you can't unbake a cake to get the flour and eggs out, you can't unvulcanize rubber.

SERUMGARD: In, for example, an aluminum can, you can take aluminum and you can crush it, you can melt it, you can form it into a can, and you can do that any number of times. There are no chemical changes that take place. Unfortunately, with rubber, there are those changes, those physical changes, that occur in processing. Even if we grind it up very small, it's still a vulcanized particle.

JOHNSON: The prospect of de-vulcanizing rubber has tantalized researchers for decades. Its promise is that it would allow tires to be transformed, essentially, back into virgin rubber. Recently, there's been progress on de-vulcanization, but people disagree about when the technology will be ready. According to professor Sy Schwartz at U.C. Davis ...

SCHWARTZ: It's already here. There is the chemical de-vulcanization process called De-Link [spells it out], that is already commercially in use, and is economical.

JOHNSON: But according to John Serumgard at the Rubber Manufacturers Association...

SERUMGARD: There are a number of processes where people claim that they have a de-vulcanization technology. And indeed they may de-vulcanize to some extent. But none of them have yet been capable of being ramped up to commercial-level production. Given the current state of the science, I would say that isn't simply years away. That's probably decades away.

JOHNSON: Whatever the reasons, de-vulcanization is not happening yet on a large scale. In the meantime, a partial solution to the problem of tire trash is to reduce the number of tires we throw away. The first element of the old mantra: Reduce, reuse, and recycle.

(Auto body shop sounds)

JOHNSON: Like most dealers, Toscolito's in San Rafael, California, sells extra-long-life tires, like the Toyo Ultra or the Goodyear Infinitred. These can last 100,000 miles. More than twice the life of an average tire. But you have to know what you're looking for.

LENOL: It was a 205-70-15, and it is a radial. And it's 95T, which implies that it's a T-rated speed-rated tire.

JOHNSON: There is a jumble of letters and numbers on the sidewall of your average tire, so salesman David Lenol says, to compare tread lifes, look for something called a UTQG rating. It's an ugly acronym that stands for Uniform Tire something or other.

(To Lenol): Is the 800 the UT --

LENOL: No, the UTQG rating would be found on the side of the tire. Right here you'd find the tread wear rating at 700.

JOHNSON: So right now, 700, that's the pretty much the highest you can get.

LENOL: Yes, at the moment that is the highest-rated tire you can purchase.

JOHNSON: The rating doesn't exactly correspond to mileage, but a tire with the rating of 700 should last twice as long as one rated at 350. Now, if people switched, or if auto companies began installing these tires on new cars, eventually the number of waste tires could be cut in half. That's more than 100 million tires a year that won't be thrown away or burned. For Living on Earth, this is Nathan Johnson in San Rafael, California.



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