Tobacco use, particularly smoking, causes a range of adverse health effects, is directly implicated in a number of serious diseases, and can increase adverse effects of other chemical, physical and biological agents. Chemicals and other agents in workplaces can cause, if not controlled, disease, incapacity and early death. In the workplace it is clear that adverse effects can be produced by the synergistic interaction of tobacco smoking and other hazards. The majority of interactions of harmful tobacco smoke constituents with toxic chemicals occur when the latter are airborne, although interactions of smoking with ingested and/or absorbed harmful agents have also been reported.