Regulationcurrent
49 CFR 178.255-4
-4 Closures for manholes and domes.
Current as of 2026-08-18 Government source
eCFR editorial compilationAuthoritative but unofficial
View source (a)The manhole cover shall be designed to provide a secure closure of the manhole. All covers, not hinged to the tanks, shall be attached to the outside of the dome by at least 1/8 inch chain or its equivalent. Closures shall be made tight against leakage of vapor and liquid by use of gaskets of suitable material.#
(b)[Reserved]#