(a) The protective seals on controllable pitch propellers must be maintained to minimize the leaking of hydraulic fluid.

(b) To the greatest extent practicable, maintenance activities on controllable pitch propellers must be conducted when a vessel is in drydock. If maintenance and repair activities must occur when the vessel is not in drydock, appropriate spill response equipment (e.g., oil booms) must be used to contain and clean any oil leakage.

(c) The discharge of controllable pitch propeller hydraulic fluid must not contain oil in quantities that:

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

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

(3) Contain an oil content above 15 ppm as measured by EPA Method 1664a (as defined in 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

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