American Chemet Corp., Deerfield, IL, announced plans to expand production capacity for cuprous oxide, a major raw material in marine antifouling paints, at the company's East Helena, MT, operations. The company said it will invest up to $5.9 million in a first phase of the expansion, which is scheduled for completion by the end of 2003. The company said the expansion would effectively double its cuprous oxide capacity. A key factor in the expansion program is a 2001 International Maritime Organization action that will lead to the prohibition of the use of organotin-containing marine antifouling paints on vessels engaged in international shipping, the company said. American Chemet said it is the world's biggest producer of cuprous oxide.