If you're responsible for managing chemicals or other hazardous materials, you'll be interested in an informative article titled simply "What is Hazardous?" that appears in the July issue of Occupational Health & Safety magazine.
The article identifies and explains the six primary hazard categories, then goes on to discuss the delicate relationship between hazard and risk. It also discusses public health hazard categories and begins a discussion of risk management.
Author David C. Breeding, CSP, CET, CHMM, addresses the conundrum surrounding hazardous materials this way: "A material of relatively low hazard can present substantial risk, while a material with a high hazard might present no measurable risk in certain circumstances."
Safety professionals commonly define hazards as anything with the potential to cause harm, while risk is the probability of a negative outcome from exposure to a hazard. These definitions are easily applied to many workplace situations, from extension cord use to machine guards.
Substances are defined as hazardous if they have one or more of the following characteristics: flammable, corrosive, toxic, or reactive. Additionally, substances are defined as hazardous if they are specifically listed by regulation. For example, OSHA, EPA, and DOT publish lists of materials deemed hazardous.
The article is good reading for anyone who works with chemicals or other "hazardous" materials.