49 C.F.R. § 176.138
Deck stowage
(a) [Reserved]
(b) Class 1 (explosives) may not be stowed within a horizontal distance of 6 m (20 feet) from any source of heat and any possible sources of ignition. With the exception of division 1.4 (explosive) materials, Class 1 (explosives) materials may not be stowed within a horizontal distance of 12 m (39 feet) from the bridge, accommodation areas, and lifesaving appliances.