By law, the parties responsible for the use, transportation, storage, and disposal of hazardous substances and oil are liable for costs. This liability applies to the cost of containment, cleanup, and damages resulting from a release related to their own activities. EPA's goal is to identify the responsible parties and ensure that they pay these costs.

Unfortunately, the responsible party sometimes cannot be identified or simply refuses to cooperate with the response effort. In such instances, EPA and other participants in the National Response System will step in to ensure that the emergency is dealt with in a timely and appropriate manner. During and after the cleanup, EPA continues to search for the responsible party and seek payment for the costs incurred. However, in some cases, the responsible party is never identified.

Congress established two funds to cover the costs of federal cleanup activities when the responsible party does not or cannot pay: the Superfund and the Oil Spill Liability Trust Fund. Congress also directed that a percentage of the Superfund be used by the Local Governments Reimbursement (LGR) Program to help offset costs involved with the clean up of hazardous substance releases.