The official state CDL manual contains all the information you need to know to pass the HazMat endorsement knowledge test. However, times change. Government and industry regulations for dealing with hazardous materials can change over time. Even after you obtain your HazMat endorsement, you'll need to keep up with those changes. (For example, in 2001, the PATRIOT Act became law, requiring HazMat drivers to be fingerprinted and undergo an extensive criminal background check.) Government regulations require training of all drivers involved in transporting hazardous materials. Your employer or a designated representative is required to provide you this training. You can also obtain and study a copy of Title 49 (transportation) of the Code of Federal Regulations (CFR). Also study your state's regulations.