The Clean Air Act requires the Environmental Protection Agency (EPA) to regulate pollution from new, modified and reconstructed facilities through the New Source Performance Standards (NSPS) program, established in Sec. 111 of the Act. (Confusingly, the New Source Performance Standard provisions of the Clean Air Act also require EPA to set standards for existing sources, as described below.) NSPS are technology-based standards which apply to specific categories of stationary sources. As with many other Clean Air Act programs, EPA establishes a federal standard for a given category of facility, which state environmental agencies then translate into requirements for individual facilities. On March 27, 2012 EPA proposed NSPS for electric power plants. None have yet been proposed for refineries.
Under Section 111(b) , EPA must establish performance standards for new and modified sources. An NSPS requires facilities to attain an emissions level that "reflects the degree of emissions limitation achievable through the application of the best system of emissions reduction which (taking into account the cost of achieving such reduction and any non-air quality health and environmental impact and energy requirements) the Administrator determines has been adequately demonstrated." In setting this performance standard, EPA has some discretion to distinguish among classes, types, and sizes of facilities within source categories. However, the limit EPA sets must take the form of a standard, and it may not prescribe a particular technology itself. The law ostensibly requires EPA to review the technological options available for emissions reduction and, if appropriate, establish a new standard every eight years, but in practice, standards have typically remained unexamined and unchanged for much longer than eight years, often because of resource constraints at EPA.
Under Sec. 111(d) of the Clean Air Act , EPA is required to set standards for existing stationary sources. Again, EPA designates categories and establishes minimum technology-based standards, and states are delegated the authority for establishment, implementation, and enforcement of these performance standards. As with implementation of the National Ambient Air Quality Standards  (NAAQS) program, EPA must approve state plans for meeting the requirements of Sec. 111(d) or implement a federal implementation plan  if the state plan is not satisfactory. Unlike the NAAQS program, Sec. 111(d) appears to allow EPA to give the states broad discretion in establishing their programs.
The definition of "refinery" EPA uses comprises establishments primarily engaged in refining crude petroleum into finished petroleum products, including gasoline, kerosene, asphalt, lubricants, and solvents, among others. Under this definition, there are 147 refineries in the United States.
Petroleum refineries have been subject to new source performance standards for a variety of pollutants since the Clean Air Act was passed in 1970. EPA is required  to establish NSPS for GHGs under the Clean Air Act, as was clarified in the US Supreme Court case Massachusetts v. EPA.
Following other required regulatory steps, in a 2010 judicial settlement , EPA committed to a timeline for promulgating NSPS for greenhouse gases for two existing source categories: power plants  and oil refineries . It held five, broad-based, sector specific listening sessions  on the topic and received comments from numerous stakeholders. The deadline for a proposed refinery rule outlined in the settlement was December 10, 2011. At EPA's request, this deadline was extended to September 30, 2011, and then a further delay was agreed to. It is not clear when EPA will release proposed regulation for refineries, but under the court-approved settlement agreement, the final refinery NSPS were due on November 10, 2012.