DENVER — Colorado Congressmen Ed Perlmutter and Mark Udall are objecting to plans by the Department of Energy to digitally copy and then destroy 500 boxes of records from the former Rocky Flats nuclear weapons plant.

The Democratic lawmakers and a community group say the records are critical to understanding the plant’s history and cleanup. They say electronic formats change and paper files are permanent records.

The Energy Department has said that personal information in the records, including Social Security numbers, make the documents a risk for identity theft.

The federal government has spent $7 billion to clean up the site 15 miles north west of Denver and turn it into a wildlife refuge.