Maybe you’re thinking of Letters from Iwo Jima? They shot on location but the island is basically a mass war grave so they couldn’t use much pyrotechnics to avoid disturbing the ground.

Empire of the Sun was mostly shot in Shanghai and Spain. That was the one where they got fined for burning old tires for the special effect smoke, which dumped a bunch of toxic smoke on Shanghai.

Yeah I don't know what movie it was - just that the topic was explosions in Japan.