Brake Pad Partnership FAQ


Q: What does SB 346 do?
A: SB 346 requires that, in order to improve and protect the state’s aquatic environment, the use of copper in brake pads sold in California be reduced to no more than 0.5% by 2025. The bill also creates limits and monitoring requirements for other brake pad materials.
Q: What do brakes have to do with the environment?
A: The answer has to do with two things: how brakes work and what they’re made of. Both disc brakes and drum brakes use brake pads to generate friction against discs or cylinders that in turn slow and stop a moving vehicle. While the car is stopping, the friction also rubs off a tiny amount of the brake pad’s “friction material.” Eventually the brake pads need replacement. Although some of the “friction material” residue (dust) created by braking remains on the wheel, in the brake cylinder, or on the car, the rest goes onto the roadway or into the air. One of the components of this dust is copper.
Q: Why is copper used in brake pads?
A: Copper performs several functions: it adds structural integrity to the brake pad material, reduces fade so that brakes remain effective through extended braking events, transfers heat efficiently, and helps brakes be more effective in cold weather. Copper also has properties that help prevent brakes from squeaking and shuddering when they are used, which is very important for car customer satisfaction and keeping warranty costs low. Not all brake pads contain copper. Copper content varies from manufacturer to manufacturer and even among pads made by the same manufacturer, but brake pads for new cars and original equipment replacement pads are generally likely to have higher copper content than other replacement pads.
Q: How does brake dust get into our “aquatic environment”?
A: Much of the dust that is emitted into the air is blown onto areas adjacent to the roadway, or is washed into the storm drains when it rains. The dust in the air can stay that way for some time and travel until it’s deposited on land. Copper deposited on soil or plants is much less likely to be washed into storm drains than copper that lands on impervious surfaces. Our urbanized areas are largely covered with impervious surfaces (roofs, pavement, etc.), which serve as highly efficient collectors for debris that gets carried into storm drains. In general, anything that gets into a storm drain ultimately flows into creeks, rivers, and marine waters. In most parts of California storm drains flow directly to creeks, rivers, and marine waters without wastewater treatment.
Q: Why is copper a problem? What is its effect on the environment?
A: Copper is a pollutant of concern in part because of its toxicity to certain sensitive species of algae (phytoplankton) that form the base of the aquatic food web. Most, if not all, of the aquatic species living in California’s near-shore coastal waters and estuaries prey on organisms that are direct or indirect consumers of phytoplankton. Copper also directly damages the sensory capabilities of salmon, making it difficult for them to avoid predators or find their way back to their spawning grounds.
Q: How do you know the copper in runoff is from brake pads? What about other sources like pipes, or pesticides, or naturally occurring copper?
A: Our studies of San Francisco Bay included estimates of copper releases from a comprehensive inventory of non-brake pad sources, including architectural copper, copper in pesticides applied to land in urban areas, copper in agricultural land applications of pesticides, copper in algaecide treatment of surface waters, copper from pressure-treated wood preservatives, copper in marine antifouling paint, copper in pool, spa, and fountain algaecides, copper in fertilizers, copper releases from industrial facilities, copper in industrial runoff and industrial releases to surface waters, copper in industrial air emissions, and copper in domestic water discharged to storm drains. We also took naturally occurring copper into account. These sources were not as important as brake pads in highly urbanized watersheds. Our studies indicated that copper from brake pads accounted for, in some cases, more than half of the human generated copper coming off of highly urbanized watersheds.
Q: Why do we need to deal with copper now?
A: In response to litigation brought by environmental groups, and pursuant to the requirements of the federal Clean Water Act, the Regional Water Quality Control Boards in Los Angeles and San Diego have already imposed severe copper Total Maximum Daily Loads (TMDLs) on municipalities that must be complied with no later than 2028. Similar TMDLs are expected to be imposed on other urban watersheds across the state in the near future. The municipalities responsible for meeting these TMDLs need to give the regulating agencies detailed plans of how they are going to reduce the copper in their watersheds immediately.
Q: Why can’t the copper in stormwater runoff be treated and removed like it is in sewer water?
A: Since much of the copper in stormwater runoff is in a dissolved form, the type of treatment technologies that are most commonly retrofitted into storm drain systems—drain inserts that remove trash and other solids—are not effective in removing it. While land-based stormwater runoff treatment systems like infiltration ponds and rain gardens are better at removing copper, widespread installation of these systems would be prohibitively expensive and could be disruptive to established communities, because these systems require significant amounts of land located near storm drain outlets along creeks, rivers, and beaches. It is estimated that the land acquisition and infrastructure costs for Los Angeles County alone could be over $1 billion. The only technically and economically feasible way to reduce copper in these watersheds is to remove it at its source – vehicle brake pads.
Q: What process led to SB 346?
A: SB 346 is based on the work of the Brake Pad Partnership, a collaborative group of brake manufacturers, environmentalists, stormwater management entities, and regulators that originally came together to understand the impact on the environment of brake pad wear debris. Before the Partnership committed to investing significant state and private resources in technical studies, the Brake Manufacturers Council (BMC) and its members (primarily manufacturers of original equipment friction materials) agreed to introduce reformulated products within five years if the technical studies indicated that copper in brake pads was contributing significantly to water quality impairment. The State Water Resources Control Board and Caltrans together contributed close to $1 million towards paying for the subsequent research into the issue. In late 2007 the Partnership completed a series of interlinked laboratory, environmental monitoring, and environmental modeling studies that indicated that brake pads are a substantial contributor to copper in runoff to the San Francisco Bay. As the technical studies’ results emerged, the Partnership shifted its focus to determining an appropriate mechanism for reducing copper in brakes in California. It concluded that the fairest and most effective way to address the challenge was with legislation – SB 346.
Q: Why is 2025 the deadline for achieving the effective elimination of copper from brake pads?
A: SB 346’s supporters recognize that the brake pad manufacturing industry needs time to do the necessary research and development of copper-free brake pads, and that the vehicle manufacturing industry also needs time to design braking systems for those new materials and incorporate them into their various platforms. However, the proponents also know that municipalities face ruinous costs and penalties if they fail to comply with their copper TMDLs. Setting the deadline in 2025 gives industry a full 14 years to develop and introduce copper-free brake pads (a process many companies have already begun), while also allowing municipalities to meet their TMDLs.
Q: What will the brake manufacturers use instead of copper?
A: Brake manufacturers are not sure what they will use to replace copper in brake friction materials but they know there will not be a one for one substitution. Rather, there will be a mix of constituents to provide the performance characteristics that copper provides. SB 346 clearly states that whatever materials are developed will have to meet all applicable safety standards.
Q: How will we know that copper isn’t being replaced with something that creates its own set of environmental problems?
A: SB 346 prohibits all but de minimis use of cadmium, hexavalent chromium, lead, mercury, and asbestiform fibers in friction materials sold in California after January 1, 2014. SB 346 also includes provisions that link it with California’s landmark Green Chemistry Initiative in order to ensure that copper will not be replaced with materials containing other harmful substances.