Section 153.219 - Access to double bottom tanks serving as dedicated ballast tanks(a) Except as prescribed in paragraph (b) of this section, access openings to double bottom tanks serving as dedicated ballast tanks must not be located within a cargo containment system.(b) Each access opening to a double bottom tank that is a dedicated ballast tank and that is located within a cargo containment system must be:(1) Enclosed in an access trunk extending to the weatherdeck;(2) Separated from the cargo containment system by two manhole coverings; or(3) Approved by the Commandant (CG-ENG).CGD 78-128, 47 FR 21207, May 17, 1982, as amended by CGD 82-063b, 48 FR 4782, Feb. 3, 1983