A bill to deduct from gross tonnage in determining net tonnage those spaces on board vessels used for waste materials.

Deducts from the gross tonnage of every vessel of the United States that space occupied by machinery used exclusively to separate, clarify, or purify a ship's own slop oil mixture or tank-cleaning residue or other waste materials, or tanks used exclusively for the carriage of such slop oil mixture, tank-cleaning residue or other waste materials, including sewage, and space occupied by any tank or tanks used exclusively for the carriage of such slop oil mixture, tank-cleaning residue or other waste materials, but not to exceed a maximum space deduction established by regulation. Provides that the Secretary of the department in which the Coast Guard is operating, in consultation with the Administrator of the Environmental Protection Agency, shall issue regulations to define the slop oil mixtures, cleaning residue, and waste materials, establish the maximum deductions which may be made, and define the manner in which the spaces shall be used and marked.