SEATTLE- Washington has become the first state in the nation to pass a law to phase out the use of copper in brake pads. The move could eventually make copper-free pads the industry standard in the U.S., according to the Associated Press. Environmentalists say the metal could pose a hazard to marine life.

Copper is a major source of water pollution because it is present in so many products, including plumbing, paint and building materials.

A study by the nonprofit Sustainable Conservation found that one-third of 530,000 lbs. of copper released from human activity in the San Francisco Bay watershed in 2003 came from automobile brake pads.

Similarly, state ecology officials in Washington estimate 70,000 to 318,000 lbs. of copper are released into Puget Sound each year, with about one-third coming from vehicles.

Brake pads contain as much as 25 percent copper, a metal used because it is good at dissipating heat, Augustine said. Heavier and high-performance vehicles tend to have more copper, but many cars already contain less than 5 percent, he said.

The new law bans brake pads containing more than 5 percent copper starting in 2021. The allowable amount could drop almost to zero in 2023 if manufacturers show it is possible, reported AP. California lawmakers have considered similar legislation, and industry officials expect other states to follow Washington's lead.

One alternative may be ceramic brake pads, which have grown in popularity in recent years, reported AP.

Researchers have yet to document any instances in nature of copper from urban runoff causing widespread problems for aquatic life. But laboratory studies by government scientists have shown that copper at the low levels that have been found in waterways harms young coho salmon's sense of smell, reducing their ability to escape from predators.

"I think this does go a long way toward eliminating a very toxic item in our marine environment," said state Sen. Kevin Ranker, who sponsored the bill.