Why changing coal types could endanger a warship

Why did the type of coal used aboard Maine matter?

Bunker design depended on the coal's properties; combustible dust from bituminous coal required greater care around ammunition spaces.

Coal bunkers were arranged around the properties of the expected fuel, including how much dust it produced. Filtration and the distance between bunkers and ammunition spaces therefore mattered to safety. Coal dust could burn and ignite nearby ammunition. Anthracite allowed somewhat closer positioning, while bituminous coal required greater caution and separation.