A health hazard: Any organism, chemical, condition, or circumstance that may cause injury or illness.
A physical hazard is an agent, factor or circumstance that can cause harm with contact. They can be classified as type of occupational hazard or environmental hazard.
Risks:
Risk is the possibility of a harm arising from a particular exposure to a chemical substance, under specific conditions.
Crossing the street presents the hazard of getting hit by a passing car. But risk is the likelihood of harm actually occurring.
Explanation: