Surveillance systems: what to include and why.

There is no question that exposure to specific substances is associated with an increased risk of developing specific neoplasms. Exposure to soot by chimney sweeps was found to be responsible for scrotal cancer by Sir Percival Pott over 200 years ago. More recently we have obtained evidence of the adverse effect of asbestos fibers, benzene, vinyl chloride, arsenicals, beryllium, and other substances that have been addressed frequently in recent literature. NIOSH publishes a handbook entitled "Pocket Guide to Chemical Hazards," which contains 450 chemicals with varying degrees of toxicity, and these represent but a small number of the substances we deal with daily. In this article, the symptoms of short-term overexposure are set forth. What is not presented here, or contained, to a very limited degree, is the risk of low-level exposure over a long period of time. The reason this kind of information is not presented is because we have limited information on this question. In most instances we just do not know what the risks are of long-term exposure or low-level exposure. But we should know this and, the fact is, we do know how to find out.