Section 791.1 - Scope and authority(a) This part establishes procedures and criteria to be used in determining fair amounts of reimbursement for testing costs incurred under section 4(a) of the Toxic Substances Control Act (TSCA) ( 15 U.S.C. 2603(a) ).(b) Section 4(c) of TSCA requires EPA to develop rules for the determination of fair and equitable reimbursement ( 15 U.S.C. 2603(c) ).