Only 15 of the 173 large-scale nonferrous metal producers in the province were included on a list of firms that complied with industry standards, and many smaller plants had expanded illegally and were discharging pollution without a permit, the MEE said.
By June, Yunnan Luoping Zinc & Electric, a major metals producer in the province, had still not disposed of nearly 100,000 tonnes of hazardous slag identified during last year's inspections, and another 100,000 tonnes of waste had accumulated at another site, the ministry added.
Yunnan Luoping Zinc could not immediately be reached for comment, but it announced in August that it had resolved all its outstanding environmental problems after signing agreements with waste recycling and transportation firms this year.