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 Rocky Flats Stewardship council, which has provided local government and community oversight of Rocky Flats since the plant closed in 1989, said it has "deep concerns" about the decision.

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

The documents aren't in the formal administrative record, which outlines the $7 billion cleanup of the site about 15 miles northwest of Denver. Most of the 6,200-acre site is being turned into a national wildlife refuge.

The documents set for destruction were housed at the Front Range Community College library in Westminster until September. Gary Morrell, librarian for the Rocky Flats Reading Room at Front Range, said the documents include community studies, state health records, geologic information, aerial radiological surveys, monitoring data and accident and incident reports.

Morell said he believes there are a limited number of documents with personal information.

Udall and Perlmutter said the decision to purge the records comes as Rocky Flats employees try to gather information on work-related illnesses.

In nearly four decades, some 70,000 plutonium triggers for nuclear bombs were made at Rocky Flats. Production was halted in 1989 because of chronic safety problems, prompting a raid by FBI agents.

The Cold War ended before production could resume. In 1993, the DOE announced that the facility's mission was over.

State and federal regulators signed an agreement in 1996 on the cleanup, including demolition of what was dubbed "the most dangerous building in America" because of leaks, spills and a fire that drove radiation levels off the charts.

Thousands of acres of open space buffered the industrial complex made up of about 800 buildings.

The wildlife refuge will not include any of the 600 acres of land where the actual plutonium trigger work took place. That area will remain closed to the public.