Why sailing navies treated black powder so cautiously

Was black powder really sensitive enough to justify elaborate magazine precautions?

Yes. A spark, flame, or excessive heat could ignite it, so navies avoided experiments and isolated every plausible ignition source.

Black powder could burn or explode after contact with a small spark or flame. The catastrophic quantity stored aboard a warship made even a low-probability ignition unacceptable. Excessive heat could also produce a dangerous result, which makes casual demonstrations of its sensitivity a poor idea. Magazine design treated prevention as the only dependable defense against losing the ship.