There are two primary areas of legislative concern with regard to cigarette smoking. The first area of concern has to do with the regulation of tobacco farming, as well as of cigarette manufacturing, labeling, distribution, advertising, promotion, and availability. These issues may be a concern because cigarette smoking is generally acknowledged by health-care officials and by the federal government to be the single most preventable cause of death in this country. Some favor the regulatory authority being assigned to the Food and Drug Administration itself, in order to further the goal of reducing tobacco use by minors. Others believe that regulatory authority belongs with Congress. A second legislative concern involves the protection of non-smokers with regard to second-hand smoke, considered by many to be a serious potential health threat. Generally, such 'clean indoor air' laws declare environmental tobacco smoke or ETS (E-T-S) a known human carcinogen, an environmental toxin, and a serious and substantial health risk for nonsmokers, especially children. Despite this information, tobacco has been typically exempt from health and safety laws enacted by Congress. In attempting to resolve these issues, generally conflicting evidence has been presented. Although considerable research seems to indicate a correlation between second-hand smoke and an increased risk for certain diseases, some parties have presented opposing evidence. Advocates for comprehensive clean indoor air laws suggest that smoking be prohibited in all public places. Currently, most states outlaw smoking in government workplaces, while less than half of the states do so for private workplaces. Some states also forbid smoking in other public places such as schools, health-care institutions, day care centers, and areas of commerce. Despite this progress towards clean air legislation, further progress may be hindered by the wording of certain related statutes, preventing local judicial authorities from putting tighter restrictions on existing state laws or enforcing their own more stringent variations of existing laws. Clean air advocates argue that such clauses may weaken stronger preexisting local laws, prevent passage of stronger future laws, and exceed usual state statutory authority limits.