The Lubricating Oils Category includes 34 lubricating oil basestocks (LOBs), also referred to as basestocks or lubricating basestocks. LOBs are derived from the refining of petroleum crude oil, primarily through the application of different processes such as solvent extraction or hydrogenation. The LOB category includes both refinery streams and finished products. The substances in this category are complex petroleum materials that typically boil between 570 to 1,110ºF (300 to 600°C) and are composed primarily of saturated hydrocarbons with carbon numbers ranging from C15 to C50. LOBs are the primary hydrocarbon components of industrial lubricants including engine oils, transmission fluids, hydraulic fluids, gear oils, metalworking oils, greases, heat transfer oils, general-purpose oils, and machine oils. The more intensively refined basestocks (reduced levels of undesirable components/impurities) may also be used as food machinery lubricants, pharmaceutical white oils, laxatives, body lotions, cosmetics, direct food additives, and products used in a number of food-contact applications. 

There are three sources of basestocks for substances in this HPV Category: 1) distillate basestocks derived from crude oil; 2) residual basestocks derived from crude oil; and 3) re-refined oil distillate basestocks. These crude oil and re-refined basestock fractions may then undergo a series of extractive or transforming processes that improve the basestocks‟ performance characteristics and reduce or eliminate undesirable components. The result is groups of lubricating oils based on the degree of processing. These groups are 1) raw or mildly refined LOBs, 2) other LOBs, and 3) white mineral oil. 

To meet the HPV Challenge, the Testing Group has thoroughly evaluated the substances within the Lubricating Oil Basestocks s category and has made all of the reliable human health and ecological hazard data available to the public. Key parameters when analyzing this category for environmental hazards are the distribution of aromatic and saturated hydrocarbons, and for some mammalian endpoints (repeated-dose, developmental, reproduction, and mutagenicity) the content and distribution of polycylic aromatic compounds (PACs) are important.

• The Category Assessment Document (CAD) for Lubricating Oils submitted to EPA by API which includes the final chemical hazard characterization and considers any new testing and analysis carried out for substances within the category.

• The Robust Summary for Lubricating Oils submitted to EPA by the American Petroleum Institute (API) which summarizes the available reliable data on physic-chemical properties, environmental fate and transport pathways, ecotoxicity, and human health toxicity.

• The EPA Screening-Level Hazard Characterization for Lubricating Oils which summarizes EPA’s views on the available data for the category and on the need for additional studies to fill data gaps.

• The API Petroleum HPV Testing Group’s response to the EPA Screening-Level Hazard Characterization for Lubricating Oils.