Two appropriations: CERCLA as amended by SARA (Superfund program) and OPA (Oil Pollution Act) authorize the U.S. Government to recover all response costs associated with cleaning up hazardous waste sites and oil spills. A large portion of EPA's response costs consists of payments to response action contractors. In order for these costs to be adequately supported in cost recovery litigation against the potentially responsible party, a defendable, logical and supportable accounting methodology must be in place that can assign costs to specific sites. The site-specific portion of the contract costs are accounted for by EPA on a site-specific basis. However, contractors' non-site-specific costs are accounted for in a general account and must be allocated to the sites in order to be recovered. This guidance provides a logical and equitable methodology for the distribution of these non-site-specific costs to the total of all sites with and without Superfund site spill identifier numbers (SSIDs) or OPA incident specific site I.D.s and program-wide non-site activities. This effort is called Annual Allocation. This document has been prepared by the Program and Cost Accounting Branch (PCAB) of the Financial Management Division. It provides instructions to contractors on how to perform the annual allocation.