46 C.F.R. § 35.30-10 Cargo tank hatches, ullage holes, and Butterworth plates—TB/ALL.
Title 46 - Shipping
No cargo tank hatches, ullage holes, or Butterworth plates shall be opened or shall remain open without flame screens, except under the supervision of the senior members of the crew on duty, unless the tank opened is gas free.
Title 46: Shipping
PART 35—OPERATIONS
Subpart 35.30—General Safety Rules
§ 35.30-10 Cargo tank hatches, ullage holes, and Butterworth plates—TB/ALL.
