FILE PHOTO: A worker drives a forklift past aluminum rolls at a factory in Huaibei, Anhui province, China March 2, 2019. Picture taken March 2, 2019. REUTERS/Stringer

BEIJING (Reuters) - China will impose an extra 5% tariff on imports of copper scrap and aluminum scrap from the United States from Dec. 15, according to a list of retaliatory tariffs published by the Ministry of Finance late on Friday.

Beijing had already levied a 25% tariff on copper scrap from the United States, one of its biggest suppliers, in a previous round of duties and twice hit U.S. scrap aluminum with a 25% tariff in 2018.

The tariffs saw China’s copper scrap imports from the United States fall by 80% year-on-year in the first half of 2019 to around 52,022 tonnes, customs data show, while aluminum scrap imports were down 16% to 229,837 tonnes.

China, the world’s biggest metals consumer, is tightening restrictions on imports of scrap metal, regardless of its origin, as part of an environmental campaign against foreign solid waste.