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.

This paper is part of a special series of publications regarding gasoline toxicology testing and gasoline risk management; this article covers regulations, standards, and industry practices concerning gasoline risk management. Gasoline is one of the highest volume liquid fuel products produced globally. In the U.S., gasoline production in 2013 was the highest on record (API, 2013). Regulations such as those pursuant to the Clean Air Act (CAA) (Clean Air Act, 2012: § 7401, et seq.) and many others provide the U.S. federal government with extensive authority to regulate gasoline composition, manufacture, storage, transportation and distribution practices, worker and consumer exposure, product labeling, and emissions from engines and other sources designed to operate on this fuel. The entire gasoline lifecycle-from manufacture, through distribution, to end-use-is subject to detailed, complex, and overlapping regulatory schemes intended to protect human health, welfare, and the environment. In addition to these legal requirements, industry has implemented a broad array of voluntary standards and best management practices to ensure that risks from gasoline manufacturing, distribution, and use are minimized.

Significant efforts have been made to characterize the toxicological properties of gasoline. There have been both mandatory and voluntary toxicology testing programs to generate hazard characterization data for gasoline, the refinery process streams used to blend gasoline, and individual chemical constituents found in gasoline. The Clean Air Act (CAA) (Clean Air Act, 2012: § 7401, et seq.) is the primary tool for the U.S. Environmental Protection Agency (EPA) to regulate gasoline and this supplement presents the results of the Section 211(b) Alternative Tier 2 studies required for CAA Fuel and Fuel Additive registration. Gasoline blending streams have also been evaluated by EPA under the voluntary High Production Volume (HPV) Challenge Program through which the petroleum industry provide data on over 80 refinery streams used in gasoline. Product stewardship efforts by companies and associations such as the American Petroleum Institute (API), Conservation of Clean Air and Water Europe (CONCAWE), and the Petroleum Product Stewardship Council (PPSC) have contributed a significant amount of hazard characterization data on gasoline and related substances. The hazard of gasoline and anticipated exposure to gasoline vapor has been well characterized for risk assessment purposes.