42 U.S.C. § 9671

As used in this subchapter— (1) Insurance The term “insurance” means primary insurance, excess insurance, reinsurance, surplus lines insurance, and any other arrangement for shifting and distributing risk which is determined to be insurance under applicable State or Federal law. (2) Pollution liability The term “pollution liability” means liability for injuries arising from the release of hazardous substances or pollutants or contaminants. (3) Risk retention group The term “risk retention group” means any corporation or other limited liability association taxable as a corporation, or as an insurance company, formed under the laws of any State— (A) whose primary activity consists of assuming and spreading all, or any portion, of the pollution liability of its group members; (B) which is organized for the primary purpose of conducting the activity described under subparagraph (A); (C) which is chartered or licensed as an insurance company and authorized to engage in the business of insurance under the laws of any State; and (D) which does not exclude any person from membership in the group solely to provide for members of such a group a competitive advantage over such a person. (4) Purchasing group The term “purchasing group” means any group of persons which has as one of its purposes the purchase of pollution liability insurance on a group basis. (5) State The term “State” means any State of the United States, the District of Columbia, the Commonwealth of Puerto Rico, Guam, American Samoa, the Virgin Islands, the Commonwealth of the Northern Marianas, and any other territory or possession over which the United States has jurisdiction.