On September 25, 2008, the U.S. Environmental Protection Agency, Region 9, made a direct referral requesting that the U.S. Department of Justice (DOJ) file a civil action against Costco Wholesale Corporation (Costco) for violations of the Clean Air Act Stratospheric Ozone Protection Provisions, 42 U.S.C. ? 7671, and the implementing regulations codified at 40 C.F.R. Part 82, Subpart F that Region 9 identified at 13 warehouses in Arizona, California, Hawaii, and Nevada. EPA expected similar violations to be found at other Costco warehouses in the United States, which includes 16 warehouses located in Illinois, three in Indiana, 11 in Michigan, six in Minnesota, seven in Ohio, and two in Wisconsin; there are approximately 429 warehouses located in all the EPA Regions. Under the settlement, Costco must implement a refrigerant compliance management system designed to prevent future violations of ozone protection requirements, and reduce its corporate-wide average leak rate from 24.1% to 19.1% or below in 2017 at 274 warehouses nationwide. The settlement also requires Costco to retrofit or replace commercial refrigeration equipment at 30 warehouses to use non ozone-depleting substances with a global warming potential of no more than 1,825. In addition, Costco must install secondary loop systems, using much less refrigerant than traditional direct expansion systems, and install centrally monitored leak detection systems, at all new warehouses.