Congress enacted New Source Review (NSR) in 1977 as a permitting program for construction of large new industrial facilities, or major modifications to existing ones. If new construction or a major modification will increase emissions by an amount large enough to trigger NSR requirements, the facility must obtain a permit before it can begin construction and install the best available air pollution control technology. States are key partners in the program. Under the Act, states have the primary responsibility for issuing permits. States are allowed to customize their NSR programs within the limits of Environmental Protection Agency (EPA) regulations. In...