A Senate subcommittee hearing has been scheduled for April 23 on a bill to create a Manhattan Project National Historical Park that includes Hanford's B Reactor.
The Energy and Natural Resources Subcommittee on National Parks will consider the bill, said Sen. Maria Cantwell, D-Wash.
A companion bill in the House has its first hearing Friday before the House National Resources Subcommittee on Public Lands and Environmental Regulation.
Historic facilities at Hanford, and in New Mexico and Tennessee, would be part of the new national park.
Similar House and Senate bills were not passed before the end of the last congressional session.
The bill has bipartisan support in the House and Senate.