On September 25, 2023, EPA issued a unilateral order ( Order ) to the Town of Barre, Massachusetts to address exceedances of its copper limits in its NPDES permit. Copper is toxic to aquatic organisms at certain concentrations and chronic exposure to copper can lead to adverse effects on survival, growth and reproduction. The Town was issued authorization to discharge under Small Wastewater Treatment Facilities General Permit on April 1, 2022, with total copper limits of 2.5 ug/l for monthly average concentration and 3.2 ug/l for daily maximum concentration. The treatment plant was not able to meet these limits based on its configuration and operation procedures. The Order requires the Town to continue optimization of current copper removal methods and to submit an annual copper optimization report that summarizes the work done to reduce the copper discharges over the past year. EPA is responsible for implementing the Clean Water Act in Massachusetts, but the Region did work in close coordination with the Massachusetts Department of Environmental Protection in this matter.