On April 25, 1979, a group of scientists who worked at the Argonne National Laboratory wrote to Senator John Glenn, the Chairman of the United States Senate Subcommittee on Energy, Nuclear Proliferation and Federal Services. They were concerned about information being leaked, in particular by the government's tacit acknowledgement that Morland's bomb design was substantially correct, something that could not otherwise have been deduced from unclassified information. These included the affidavits by the United States Secretary of Defense Harold Brown and government expert witness Jack Rosengren. Copies of the letter were sent to major newspapers, but with a cover note explaining that it was for background information and not publication. After about four weeks, the Glenn subcommittee forwarded it to the DOE, which classified it.