Proposed changes to US federal emissions regulations could force manganese alloy producers Eramet Marietta Inc and Felman Production LLC to undertake multimillion-dollar upgrades to their facilities.

The US Environmental Protection Agency is proposing amendments to national emissions standards for hazardous air pollutants that would affect Eramet's Marietta, Ohio, ferro-manganese smelter and Felman's Letart, West Virginia, silico-manganese facility.

• [Editor:Sophie]