46 CFR § 153.545 - Special requirements for liquid sulfur.
(a) A containment system carrying liquid sulfur must have:
(1) A cargo tank ventilation system that:
(i) Maintains the H2S vapor concentration below 1.85 percent by volume; and
(ii) Prevents sulfur buildup within itself; and
(2) An alarm system designed to operate when the ventilation system blower fails.