Genetically engineered crops are subject to approval by the Animal and Plant Inspection Service of the U.S. Department of Agriculture, which must prepare an Environmental Assessment to be approved for commercial use. Environmental groups brought suit under the National Environmental Policy Act (NEPA) arguing that the assessment was inadequate, and the trial court issued a permanent injunction against the use of the genetically engineered product (alfalfa) until a more extensive environmental impact statement could be prepared.
The Supreme Court decided that environmental plaintiffs are required to show irreparable harm to obtain the injunction. A permissive ruling would have made it much easier for environmental plaintiffs to stop the sale of certain products that are subject to government approval.