A proposal to bring down four hydroelectric dams near the California-Oregon border cleared a major regulatory hurdle Thursday, setting the stage for the largest dam demolition project in U.S. history to save imperiled migratory salmon.

The Federal Energy Regulatory Commission action comes after the demolition proposal almost fell apart last summer, but then a new agreement and additional funding revived it. Thursday’s ruling will allow the utility that runs the dams, PacifiCorp, to transfer its hydroelectric license jointly to the nonprofit Klamath River Renewal Corporation, Oregon and California.

Regulators still must approve the actual surrender of the license. Dam removal could start in 2023.