The new U.S. tax law could put the restoration of old buildings at risk.

While the federal historic tax credit has been retained, the 20% reimbursement for certain costs related to revitalization projects is now spread over five years rather than one. Developers, preservationists and banks oppose this new policy, fearing that it will reduce the value and prevent these projects from moving forward, the Wall Street Journal reports.

The credit, which was put in place in 1976, has led to the restoration of an estimated 42,000 buildings across the U.S., including the Wrigley Building in Chicago and the Old Post Office in Washington, D.C.

Some states are taking matters into their own hands by implementing state-level historic credits. Maryland, New York and Michigan have all begun to examine the possibility of introducing programs to allow developers to continue to use the credit as an incentive for banks and corporations to invest in historic projects.

But while some have expressed concern over the changes, others have expressed relief that the credit had not been cut altogether, as was discussed in earlier versions of the tax bill.