What are the reporting requirements for discharges of oil?

If a discharge of oil reaches waters of the United States, it is reportable to the NRC under 40 CFR Part 110, which was established under the authority of the CWA. Discharges of oil must be reported if they "(c)ause a film or sheen upon or discoloration of the surface of the water or adjoining shorelines or cause a sludge or emulsion to be deposited beneath the surface of the water or upon adjoining shorelines."