The Report on Carcinogens (RoC) is a congressionally mandated, science-based, public health document that identifies and discusses agents, substances, mixtures, or exposure circumstances (hereinafter referred to as "substances") that may pose a hazard to human health by virtue of their carcinogenicity. For each listed substance, the report contains a substance profile which provides information on (1) the listing status, (2) cancer studies in humans and animals, (3) studies of genotoxicity (ability to damage genes) and biologic mechanisms, (4) the potential for human exposure to these substances, and (5) Federalregulations to limit exposures. Eight substances have been added to this 12th ed. of the report, which now includes 240 listings. The industrial chemical formaldehyde and a botanical known as aristolochic acids are listed as known human carcinogens. Six other substances captafol, cobalt-tungsten carbide (in powder or hard metal form), certain inhalable glass wool fibers, o-nitrotoluene, riddelliine, and styrene are added as substances that are reasonably anticipated to be human carcinogens. Figures. This is a print on demand report.