The laws aim to protect both states' salmon population from the harmful effects of brake dust.
"Rather than outright killing the fish, [the copper] just renders them unable to smell," explained David Baldwin, a research zoologist at the Northwest Fisheries Science Center. "For fish, smell is a really important sensory system."
The laws that the two states have passed are not exactly identical. California's law gives parts manufacturers and automakers until 2025 to reduce the amount of copper found in brake pads to 0.5 percent by weight or less.
Washington plans to begin researching whether or not it's possible in the first place to significantly reduce copper in brake pads in 2015. Copper is typically used as a friction material so replacing it with something else involves a fair amount of testing.
If replacing copper is deemed doable, Washington will give automakers and parts manufacturers eight years to comply with the new law, meaning that it will come into full effect in 2023 at the very earliest.
If both laws are implemented as planned brake pads with less copper will likely be sold throughout the United States. Parts manufacturers estimate that it will cost too much money to provide just two states with them.
