49 CFR 176.600
General stowage requirements.
(a)Each package required to have a POISON GAS, POISON INHALATION HAZARD, or POISON label, being transported on a vessel, must be stowed clear of living quarters and any ventilation ducts serving living quarters and separated from foodstuffs, except when the hazardous materials and the foodstuffs are in different closed cargo transport units.#
(b)Each package required to have both a POISON GAS label and a FLAMMABLE GAS label thereon must be segregated as a Division 2.1 (flammable gas) material.#
(c)Each package bearing a POISON label displaying the text “PG III” or bearing a “PG III” mark adjacent to the poison label must be stowed away from foodstuffs.#
(d)Each package of Division 2.3 (poisonous gas) material or Division 6.1 (poison) material that also bears a FLAMMABLE LIQUID or FLAMMABLE GAS label must be stowed in a mechanically ventilated space, kept as cool as reasonably practicable, and be protected from sources of heat and stowed away from potential sources of ignition.#