Hazardous Materials (HazMat) Transport Practice Test 2026 - Free HazMat Practice Questions and Study Guide

Class 8 covers corrosive materials—substances that can destroy exposed skin and that can also corrode container metals. The defining criteria are that they cause skin burns or destruction within about four hours of contact and they corrode steel or aluminum at a rate of roughly a quarter inch per year. Describing class 8 this way matches the reality that these materials pose two hazards at once: they injure people on contact and they can degrade the integrity of the packaging. That’s why corrosive liquids or solids, capable of that level of metal corrosion and skin damage, are categorized as corrosives. Other hazard types involve gases (like flammable or toxic gases) or radioactive materials, which are different classes and don’t meet the corrosive criteria described for Class 8.