[Code of Federal Regulations] [Title 46, Volume 1] [Revised as of Octobery 1, 2004] From the U.S. Government Printing Office via GPO Access [CITE: 46CFR35.30-10] [Page 476] TITLE 46--SHIPPING CHAPTER I--COAST GUARD, DEPARTMENT OF HOMELAND SECURITY PART 35_OPERATIONS--Table of Contents Subpart 35.30_General Safety Rules Sec. 35.30-10 Cargo tank hatches, ullage holes, and Butterworth plates --TB/ALL. 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.