The compressed air that is used in air brake systems can be hazardous if you get near it when it is being exhausted from the vehicle. Compressed air leaving the vehicle travels at a very high speed and carries moisture, oil, dirt and dust. Plus there is always the chance of an accident in procedures that require you to release the brakes and crawl underneath your vehicle to inspect various items. While you’re inspecting the air brakes, wear a bump cap or hard hat, safety glasses, a visible safety vest, and steel toe boots.