Check the article and photos at the link. It happened in that quantity. Debris blown 22 miles away.
Photos at the link, include hundreds of 14” naval gun rounds, without their detonators certainly but full of HE. Standing there taking the photo? Not me.
Other photos show multiple intact rounds laying around. 4” , 88mm equiv.
Oh yeah, it happened. Must have made a hell of a boom.
If it was 600,000 tons I think it should have been bigger. It would be equivalent of 30,000 tractor trailers with 40,000 pound a piece. But I think I know what they are saying, 600,000 tons of munitions, not explosives. A pound of rifle ammunition has just an ounce or so of explosives in them.