The Japanese government lobbied hard for a global pact that limits mercury use and to name the resulting treaty after Minamata, the site of a homegrown industrial disaster from the 1950s when the toxic metal poured into a river, poisoning thousands.

But a year after the Minamata Convention on Mercury was agreed to in Kumamoto Prefecture, Japanese industries from smelters to cement makers are digging in to fight the storage costs and emission curbs the still-pending treaty would impose.

The international pact, so far only ratified by the United States as other nations take time to iron out domestic regulations, would require countries to ban nearly all exports of the poisonous material.