Maine’s largest affordable housing developers are at a loss.

Ten projects that would add more than 400 sorely-needed units to the state’s low-income housing stock are fully permitted and ready to go.

But none can break ground because of a new federal rule designed to boost American manufacturing.

The Build America Buy America Act, signed by President Joe Biden in late 2021 as part of the Infrastructure Investment and Jobs Act, requires all building projects using certain government funds to source 95% of their construction materials from the United States.