Multi-state lawsuit challenging EPA failure to act on petition requesting that the agency regulate ozone pollution from sources in upwind states.

Settlement of consumer protection claims raised by a multi-state coalition of state attorneys general against Volkswagen for selling vehicles equipped with “defeat device” software intended to circumvent emissions standards and concealing this software from regulators and the public.

Letters and testimony providing recommendations on federal legislation amending the Toxic Substances Control Act (TSCA) to revise the process and requirements for evaluating and determining whether regulatory control of a chemical is warranted.

Multi-state intervention to join EPA’s defense of Clean Power Plan against challenge mounted by other states and industry petitioners.

Multiple states joined as defendant-intervenors in support of EPA in lawsuit challenging New Source Performance Standards (NSPS) for carbon dioxide emissions from new and modified power plants.

Multiple states intervened in lawsuit to defend EPA standards regulating mercury and other air pollutants from the power sector.

Multiple states intervened in lawsuit to defend EPA rules concerning regulation of greenhouse gas emissions from stationary and mobile sources.

Multi-state lawsuit challenging the adequacy of EPA’s 2006 revision to the National Ambient Air Quality Standards (NAAQS) regulating soot pollution under the Clean Air Act.

Multi-state challenge to EPA decision to remove fossil fuel-fired power plants from list of sources regulated under CAA section 112 (hazardous air pollutants) and to establish new performance standards for mercury emissions from these plants under CAA section 111.

Multi-state action against EPA for failure to set NSPS standards for oil refineries.

Multi-state litigation under Clean Air Act alleging violations of New Source Review permitting process to reduce sulfur dioxide emissions in coal-fired power plants.

Multi-state challenge to 2002 EPA rule amending and expanding the routine maintenance, repair and replacement exceptions to the New Source Review program.

Multi-state lawsuit challenging the Department of Energy (DOE)’s failure to create energy efficiency standards for consumer appliances according to the timeline established by the Energy Policy and Conservation Act (ECPA).

Multi-state challenge to 2002 EPA rule amending the New Source Review (NSR) program and narrowing the definition of “modification” to exclude certain sources from NSR requirements.