The environmental cost of a scrapped tire, and why reuse matters

A tire is built to shrug off heat, water, sunlight, and tens of thousands of miles of road. That toughness is the problem: it doesn't rot away once you're done with it. So what does a scrapped tire actually cost the environment? More than the landfill picture suggests, and less than some of the numbers you have probably seen.

How many tires does the US throw away every year?

About 264 million tires reached the end of their life in the US in 2023, per the US Tire Manufacturers Association (USTMA), the industry's trade group. It is the best number going, though a trade estimate, not a government count; the EPA stopped running a national scrap-tire program years ago. If you have seen "300 million" instead, that is an older, broader count from the early 2000s, not a contradiction.

79% reused, 19% dumped USTMA reports 79% of 2023's end-of-life tires reached a beneficial end market, up from 71% in 2021. The other one in five (19%, about 874,000 tons) went to land disposal. Source: USTMA 2023 End-of-Life Tire Management Report.

Where do the reused ones go? Mostly two places: tire-derived fuel at about 33%, burned for energy in cement kilns and paper mills, and ground or crumb rubber at about 28%, for playground surfacing, athletic fields, and molded products. Civil-engineering projects take another 6% or so. That is real progress from the tire mountains of the 1990s, but burning a tire for fuel is not the same as keeping it out of the environment.

Why is a pile of tires a hazard?

The big one is fire, and a tire fire is almost impossible to put out. Burn one passenger tire and it gives up more than two gallons of oil. The EPA estimated a fire consuming a million tires can release about 55,000 gallons of oily runoff. Water and foam barely help; crews often end up smothering it with dirt, and the smoke carries benzene, styrene, butadiene, polycyclic aromatic hydrocarbons, and heavy metals. In 1983 the Rhinehart fire in Virginia burned an estimated 5 to 7 million tires for about nine months and became a Superfund site the EPA did not finish cleaning until 2005, at a cost near $11.8 million.

Piles do slower damage too. Each tire holds a pocket of stagnant water that breeds mosquitoes; the disease-carrying Asian tiger mosquito spread to 678 US counties partly through used-tire shipments (CDC). And tire crumb leaches zinc and polycyclic aromatic hydrocarbons into water, worse under sunlight.

The pollution you cannot see: tire particles and 6PPD-quinone

When people picture tire waste, they picture a landfill. The bigger and newer problem is microscopic. Every mile you drive, your tires shed tiny particles onto the road, and rain washes them into waterways.

The most cited figure is a 2017 IUCN study that pinned about 28% of the primary microplastics reaching the oceans on tires, with tires and synthetic textiles together at roughly two-thirds. You will also run into bigger claims: that "tire dust is 78% of ocean microplastics," or that tire wear is "1,000 times worse than exhaust." Both are overstated. The 78% is poorly sourced, and peer-reviewed estimates put tire wear closer to 5 to 10% of the plastic entering the ocean. The inflated version just travels faster than the real one.

The big shift came in 2020, when researchers writing in Science named 6PPD-quinone as the chemical behind mass die-offs of coho salmon returning to urban streams. 6PPD is in nearly every tire, up to about 2% of its mass, added to keep the rubber from cracking. When it meets ozone in the air it becomes 6PPD-quinone, which kills coho at about 95 nanograms per liter, one of the most toxic substances known for a fish, though the sensitivity is very species-specific. Regulators moved fast: California listed 6PPD tires as a Priority Product in 2023, Washington passed a law in 2024, and the US EPA opened a formal rulemaking in November 2024.

So where does a used-tire marketplace fit?

The EPA's own waste hierarchy puts reuse above recycling: reduce, then reuse, then recycle, then energy recovery, then disposal. Keeping a sound tire in service beats grinding a good one into crumb or burning it, because it also spares the oil and materials of the new tire you would have bought instead.

Three caveats, so nobody oversells it:

• Reuse delays scrap, it doesn't erase it. Every tire ends up as waste eventually. Selling a sound used tire buys it years; it does not solve the end-of-life problem.
• We are not a recycler. Our contribution is reuse, keeping good tires rolling longer. Tires that fail inspection are rejected and never listed, so they do not get a second life on the road.
• Grading is a safety tool first. The point of a published standard is to keep unsafe tires off the road. The environmental payoff is a side effect: good tires get used up fully instead of scrapped early out of caution.

The exact bar behind every letter grade is published in full, as the RealTreads Standard. And if you are still weighing whether a used tire can be a responsible choice at all, we wrote a companion piece: Are used tires safe? The stigma versus the real risks.