In 1989, the Town of Clarkstown, New York (plaintiff) entered into an agreement with the New York State Department of Environmental Conservation. The agreement stated that Clarkstown would close its current landfill and hire a private contractor to build a new waste processing facility. To help pay for the cost of the new facility, Clarkstown enacted a “flow control ordinance” which required all solid waste to be processed at the new facility before leaving the municipality for a fee of $81 per ton of waste processed. The fee was paid to the contractor to offset the cost of building the facility. C&A Carbone (defendant) operated a competing waste-processing plant in Clarkstown. While the flow control ordinance allowed Carbone to continue operating, it required them to ship all non-recyclable waste to the Clarkstown facility and pay the $81 fee. In 1991, a tractor-trailer owned by Carbone crashed and police discovered it was illegally transporting solid waste to an Indiana landfill to avoid paying the fee at the Clarkstown plant. The town sought an injunction requiring Carbone to ship its waste to the town facility. In state court Carbone then challenged the flow control ordinance on the grounds that it violated the Commerce Clause. The court ruled in favor of Carbone and placed an injunction on enforcement of the ordinance. The Court of Appeals of New York reversed and ruled in favor of Clarkstown. The United States Supreme Court granted certiorari.