Citing concerns over copper leaching into waterways and the environment, Washington State has passed a law phasing out the use of copper alloy brake pads. Copper’s heat dispersing capacity made it a good replacement for asbestos brake pads in the 1990s. Environmental regulators couldn’t point to any one problem caused by copper, but the Evergreen and ever-rainy state of Washington is concerned about what all this metalic dust might due to it’s salmon industry.