In 2002, the Defendant began construction on a glass furnace expansion project at its glass manufacturing facility located in Elmira, New York. The furnace expansion was a major modification under the Prevention of Significant Deterioration of air quality (PSD) regulations at 40 C.F.R. 52.21, which caused a significant net emission increase of nitrogen oxides (NOx), sulfur dioxide (SO2) and particulate matter of 10 microns or less (PM-10). Specifically, the Defendant failed to obtain a preconstruction PSD permit for the furnace expansion that includes a requirement to apply the best available control technology with respect to NOx, SO2 and PM-10 emissions from the furnace.