What is PA-12 and Why is it Worrying Automakers?

DETROIT — Who knew that an obscure chemical called PA-12 would be so important to the auto business?

It's a key ingredient in nylon used to make plastic auto parts, pipelines and other items. The resin is made by only a handful of companies, and an explosion at a German plant last month took a major global supplier off line.

Now that it's in short supply, companies that make everything from cars to sporting goods are trying to figure out what to do. The shortage could cause auto plants to shut down within weeks and crimp the flow of vehicles to your local dealer.

Here's more about the resin and why it's so important.

Q: What is this stuff?

A: In the chemical business it's called a polyamide resin, a form of nylon that can be molded into plastic pipes, tubes and hoses to carry vapors, fuel and other liquids. A single molecule has 12 atoms of carbon and one atom of nitrogen. The rest is hydrogen. It melts at 302 degrees Fahrenheit and then can be molded into many shapes, says Sadhan Jana, a professor of polymer engineering at the University of Akron in Ohio.

Q: Why is it so important?

A: Few, if any, plastics can do what PA-12 does. The chemical, which came out in 1979, contains little nitrogen. Plastics with less nitrogen absorb less moisture. When nylon absorbs moisture, it weakens and can deteriorate, causing leaks. So tubing made of PA-12 can carry gasoline, brake fluid and other liquids without decomposing, says Jana. It also resists ethanol, which now makes up 10 percent of U.S. gasoline.

Q: Where is it used?

A: In fuel lines, brake lines, pipelines — even the handles of certain power tools. PA-12 also is used in plastics for car seats and a number of consumer and sporting goods.

Q: Why is PA-12 in such short supply?

A: Not many companies make it, and because of heavy demand from the auto and other industries, PA-12 already was in short supply before the March 31 explosion and fire at the Evonik Industries plant in western Germany. Evonik also made 70 percent of the world's supply of cyclododecatriene, or CDT, a critical building block used by other companies to make PA-12. Other suppliers already were cranking out as much as PA-12 as they could.

"Not many companies produce it, and that's what's led to all this mess after the explosion," says Jana.

Q: Are there any substitutes?

A: Yes, but Jana knows of none as durable as PA-12. DuPont CEO Ellen Kullman, a former General Motors board member, said Thursday that her company is working with automakers to develop alternatives.

Any substitute plastic would have to go through rigorous testing to make sure it would work for a specific automotive part, Jana says. Those tests could take months. Italian automaker Fiat SpA says it switched all of its parts away from PA-12 last year to PA-6,6, a similar nylon resin.

AP Business Writer Colleen Barry contributed to this report from Milan, Italy.