Some brake dust can be seen when a brake drum is removed from the car, truck, or other equipment. But there are also many very small dust particles that can't be seen with the naked eye. These invisible particles may be asbestos or other brake lining materials. Breathing these particles can damage your health. Many years after breathing them, they may cause shortness of breath, lung disease, or cancer.
Asbestos is only one of many materials used in brake linings today.
The only sure way to know what is in the dust from a particular brake is to test it in a laboratory. Since some newer brake lining materials are still being tested, caution is necessary. The only practical way to protect your health and those around you is to control the release of brake dust in your garage to the lowest level possible. That Release Brake Dust Into The Air Air Hose. This blows brake dust into the air in your garage, it is one of the worst things you can do, and now it is illegal.