A GHS-consistent approach to health hazard classification of petroleum substances, a class of UVCB substances.

The process streams refined from petroleum crude oil for use in petroleum products are among those designated by USEPA as UVCB substances (unknown or variable composition, complex reaction products and biological materials). They are identified on global chemical inventories with unique Chemical Abstract Services (CAS) numbers and names. The chemical complexity of most petroleum substances presents challenges when evaluating their hazards and can result in differing evaluations due to the varying level of hazardous constituents and differences in national chemical control regulations. Global efforts to harmonize the identification of chemical hazards are aimed at promoting the use of consistent hazard evaluation criteria. This paper discusses a systematic approach for the health hazard evaluation of petroleum substances using chemical categories and the United Nations (UN) Globally Harmonized System (GHS) of classification and labeling. Also described are historical efforts to characterize the hazard of these substances and how they led to the development of categories, the identification of potentially hazardous constituents which should be considered, and a summary of the toxicology of the major petroleum product groups. The use of these categories can increase the utility of existing data, provide better informed hazard evaluations, and reduce the amount of animal testing required.

Asphalt fume dermal carcinogenicity potential: II. Initiation-promotion assay of Type III built-up roofing asphalt.

Clark et al. (accepted for publication) reported that a sample of field-matched fume condensate from a Type III built-up roofing asphalt (BURA) resulted in a carcinogenic response in a mouse skin bioassay, with relatively few tumor-bearing animals, long tumor latency and chronic skin irritation. This mouse skin initiation/promotion study was conducted to assess possible mechanisms, i.e., genotoxic initiation vs. tumor promotion subsequent to repeated skin injury and repair. The same Type III BURA fume condensate sample was evaluated in groups of 30 male Crl:CD1® mice by skin application twice per week (total dose of 50 mg/week) for 2 weeks during the initiation phase and for 26 weeks during the promotion phase. Positive control substances were 7,12-dimethylbenz(a)anthracene (DMBA, 50 µg applied once) as an initiator and 12-O-tetradecanoyl-13-acetate (TPA, 5 µg, applied twice weekly) during the promotion phase. During the 6 months of study with the asphalt fume condensate, eight skin masses were observed when tested for initiation, five of which were confirmed microscopically to be benign squamous cell papillomas. Only two papillomas were observed when tested for promotion. There was no apparent relationship between skin irritation and tumor development in this study. These results are more indicative of genotoxicity rather than a non-genotoxic mode of action.