(a) All surface vessels must employ management practices that will minimize leakage of oil and other harmful pollutants into the bilge.

(b) Surface vessels equipped with an oil-water separator must not discharge bilgewater and must only discharge oil-water separator effluent through an oil-content monitor consistent with paragraph (c) of this section. All surface vessels greater than 400 gross tons must be equipped with an oil-water separator. Surface vessels not equipped with an oil-water separator must only discharge bilgewater consistent with paragraph (d) of this section.

(c) The discharge of oil-water separator effluent:

(1) Must not contain oil in quantities that:

(i) Cause a film or sheen upon or discoloration of the surface of the water or adjoining shorelines; or

(ii) Cause a sludge or emulsion to be deposited beneath the surface of the water or upon adjoining shorelines; or

(iii) Contain an oil content above 15 ppm as measured by EPA Method 1664a (as defined at 40 CFR 136.3) or other appropriate method for determination of oil content as accepted by the International Maritime Organization (IMO) (e.g., ISO Method 9377) or U.S. Coast Guard; or

(iv) Otherwise are harmful to the public health or welfare of the United States.

(2) Must not contain dispersants, detergents, emulsifiers, chemicals, or other substances added for the purposes of removing the appearance of a visible sheen. This performance standard does not prohibit the use of these materials in machinery spaces for the purposes of cleaning and maintenance activities associated with vessel equipment and structures.

(3) Must only contain substances that are produced in the normal operation of a vessel. Oil solidifiers, flocculants or other additives (excluding any dispersants or surfactants) may be used to enhance oil-water separation during processing in an oil-water separator only if such solidifiers, flocculants, or other additives are minimized in the discharge and do not alter the chemical make-up of the oils being discharged. Solidifiers, flocculants, or other additives must not be directly added, or otherwise combined with, the water in the bilge.

(4) Must not occur in port if the vessel has the capability to collect and transfer oil-water separator effluent to an onshore facility.

(5) Must be minimized within one mile of shore.

(6) Must occur while sailing at speeds greater than six knots, if the vessel is underway.

(7) Must be minimized in federally-protected waters.

(d) The discharge of bilgewater (i.e., wastewater from the bilge that has not been processed through an oil-water separator):

(1) Must not occur if the vessel has the capability to collect, hold, and transfer bilgewater to an onshore facility.

(2) Notwithstanding the prohibition of the discharge of bilgewater from vessels that have the capability to collect, hold, and transfer bilgewater to an onshore facility; the discharge of bilgewater:

(i) Must not contain dispersants, detergents, emulsifiers, chemicals, or other substances added for the purposes of removing the appearance of a visible sheen. This performance standard does not prohibit the use of these materials in machinery spaces for the purposes of cleaning and maintenance activities associated with vessel equipment and structures.

(ii) Must only contain substances that are produced in the normal operation of a vessel. Routine cleaning and maintenance activities associated with vessel equipment and structures are considered to be normal operation of a vessel.

(iii) Must not contain oil in quantities that:

(A) Cause a film or sheen upon or discoloration of the surface of the water or adjoining shorelines; or

(B) Cause a sludge or emulsion to be deposited beneath the surface of the water or upon adjoining shorelines; or

(C) Contain an oil content above 15 ppm as measured by EPA Method 1664a (as defined at 40CFR 136.3) or other appropriate method for determination of oil content as accepted by the International Maritime Organization (IMO) (e.g., ISO Method 9377) or U.S. Coast Guard; or

(D) Otherwise are harmful to the public health or welfare of the United States.

(iv) Must be suspended immediately if a visible sheen is observed. Any spill or overflow of oil or other engine fluids must be cleaned up, recorded, and reported to the National Response Center immediately.