When vehicle manufacturers and brake material suppliers

The Occupational Safety and Health Association (OSHA) also states that it is safe to have asbestos fiber content in people's work environment of no more than 0.2 per square meter, and to minimize asbestos dust generated during daily brake repair work. Try to avoid work that may cause dust to be released (such as hitting brake pads, etc.).

But in addition to health hazards, there are another important issues with asbestos brake pads. Because asbestos is adiabatic, its thermal conductivity is particularly poor. Usually, the brakes are used repeatedly to accumulate heat in the brake pads. After the brake pads become hot, its braking performance changes, and the same friction and braking force are generated. It will require more brakes. This phenomenon is called “brake atrophy”. If the brake pads reach a certain heat, it will cause the brake to malfunction.

When vehicle manufacturers and brake material suppliers decided to develop new and safer alternatives to asbestos, new friction materials emerged almost simultaneously. This is the "semi-metal" mixture type and the non-asbestos organic type (NAO) brake pad to be discussed below.