Respondent is the operator of an aerosol and non-aerosol product manufacturing and packaging facility. The Facility, including its chemical storage tanks, is located less than 0.1 mile from the nearest neighboring commercial/industrial facility. There are several commercial facilities within a 1,000 foot radius of the Facility. Respondent manufacturers and packages into personal-sized containers a number of common cosmetic and home-use fragrance aerosol products using various aerosol propellants, including pure difluoroethane and blended combinations of difluoroethane-isobutane, difluoroethane-propane, and difluoroethane-isobutane-propane. On April 1, 2013, EPA conducted an inspection at the Facility to evaluate Respondent’s compliance with the requirements of the CAA’s risk management program. During the inspection, EPA observed four horizontal ASTs (two 2,550 gallon with maximum 16,878 lbs. capacity each and two 1,990 gallon with maximum 7,983 lbs. capacity each) situated in an outdoor Propellant Storage and Transfer Yard (“Tank Yard”).