Question: what are the two major categories of chemical hazards?
Answer: Explosive (exploding bomb)
Flammable (flame)
Oxidizing (flame above a circle)
Corrosive (corrosion of table and hand)
Acute toxicity (skull and crossbones)
Hazardous to environment (dead tree and fish)
Health hazard/hazardous to the ozone layer (exclamation mark)