Turning tires to energy is one way to deal with the billions of tires that usually end up in landfills around the world.

And it's become more popular in the last decade—industrial-scale plants popping up in China, the United States, and Canada.

The process is especially valuable in Turkey, which imports most of its oil and gas, and it contributes at least $8 million a year to Turkey's economy, according to ERA Environmental Technologies.

(Turkish) It simply looks like a tire, but is a rich resource.

Automakers produced three billion tires worldwide last year.

The key ingredient in most of those tires is synthetic rubber made from petroleum.

Basically, tires are poisonous for the environment.

Pollution from car tires washes into waterways in the Pacific Northwest, and scientists say it's killing salmon populations.

And down the line, they eventually release chemicals into groundwater and air if they are left to break down in landfills.

So what can we do with them?

I'm strongly in favor of anything but just landfilling them. That makes no sense whatsoever.

But what you wanna do is, as responsibly as possible, get the most value out of this.

Tires can be burned to create energy, but experts say they can also be highly toxic.

What I think is happening is it's all the other stuff that's put into the tire in addition to the petroleum, like the sulfur.

It's when you burn that that you start to get this increase in toxicity.

That's where the problem is — not the petroleum, per se. It's all the other junk that's incorporated in the petroleum to make it into a tire.

So what about finding new uses for old tires?

They can be used to produce cement, or ground into crumbs and shaped into mats, like the ones used in playgrounds.

In India, one startup company turns tires into fashionable sandals.

Still, energy's becoming the main destination for the thousands upon thousands of tires we throw away yearly.

The tire-fueled power plant in Turkey recycles 20,000 tons every year.

(Turkish) We both contribute to the country's economy by generating electricity, and we also eliminate the environmental damage of the tire, one of the world's most dangerous wastes.

First, machines use magnets to separate the thin metal wires from inside the tires.

The rubber that's left is heated to produce something called pyrolytic oil.

The oil can then be burned to generate electricity.

It's still not the most environmentally friendly process overall.

But it does mean that these hunks of rubber, coated in fuel and fueled with byproducts, that could have sat in landfills releasing harmful chemicals for decades,

are instead powering Turkish homes and contributing to the economy.

It's really great material. I mean, after all, a little bit of it's lost by erosion on the surface of the tire.

And at some point, there isn't enough tread to use it before, but most of the tire is still there.

So let's use all of that technology that created such a great material in the first place. Let's use it again.