Alcoa Inc’s plans to close its 269,000 tonne-per-year Warrick smelter, announced on Thursday, will bring U.S. aluminum output to its lowest level in more than 65 years as the industry endures tumbling prices amid rising trade tensions with China.

Warrick is the largest currently-operating smelter in the United States and the biggest shoe to drop in a string of recent curtailments and closures, potentially boosting prices and possibly bolstering some U.S. producers’ claims they are harmed by subsidized Chinese production.

The Evansville, Indiana plant’s closure, which will take place by the end of the first quarter, will leave Alcoa with just one active smelter: the 130,000 tonne-per-year Massena West plant, which was saved from closure with $70 million in New York state aid…