While there is no absolute proof that cancer will not occur from a one-time exposure, all the evidence indicates that repeated exposure over a long period of time is necessary before cancer develops. There is a tendency to believe that if only small amounts of a chemical are needed to cause poisoning, then the chemical is highly hazardous. This is not necessarily so. A highly toxic chemical can have a low health hazard if it is used with proper precautions and care. On the other hand, it is possible that a chemical of low toxicity may present a high health hazard if it is used carelessly or inappropriately.
Toxicity is a measure of the poisoning strength and is an unchanging characteristic of a chemical.
Hazard is not the same. It is a variable feature of a chemical. Hazard is the likelihood that a chemical will cause poisoning, given its poisoning strength and the amounts and manner in which it is used, stored and handled. The toxicity of a chemical cannot be changed, but the hazard it presents can be controlled and minimized. OSH Answers Search Help OSH Answers Search is designed to help you specifically target items about Occupational Health and Safety that are explained in the OSH Answers portion of our site.