It is a possibility that one of the modified 16-Inch AP projectiles,
which the Japanese used for bombs, might have penetrated the 4-1/4-Inch STS armored deck and initiated a fire followed by a detonation of the smokeless powder magazines.
This seems rather improbable,
though, considering the small charge of explosive (less than 70 pounds of TNT) in this type of bomb, and the fact (pictures 46-208) that the initial fire was definitely above the waterline and of large-scale proportions.

この部分ですね。