Hazard communication: the case for category IV "cancer information"

Chemical hazard labeling is changing in order to convey information to a broad spectrum of the public. In addition to standard hazard warnings, supplemental information which includes the enumeration of a wide range of possible adverse effects which may occur under conditions of overexposure is also appropriate. With regard to cancer hazard warnings, known human carcinogens and even confirmed animal carcinogens are fairly easy to identify. The new American National Standards Institute, Inc., guidelines are recommending that cancer hazard warnings be limited to these known human and animal carcinogens. It seems appropriate, however, to extend cancer label statements to encompass information about certain animal tests which are indicative of some degree of carcinogenic activity, but which are not believed to be relevant to human risk in the classical sense when consideration is given to all of the data. This information concerning carcinogenicity test results and their relevance to humans can be added to label text but need not be in the form of a warning.