“Medical facilities currently are not required to take any specific actions to make sure these materials are safe, and many have very sloppy practices, which is remarkable nearly 11 years after 9/11,” the report says, according to a copy of the draft scheduled for release Tuesday and provided to The Washington Post.

The GAO evaluated efforts by the Nuclear Regulatory Commission and the National Nuclear Security Administration to regulate and secure the materials.

The report said the NNSA had completed security upgrades at only 321 of 1,503 medical facilities it identified as high-risk because they store extensive amounts of radiological material. The NNSA said it would not be able to complete upgrades until 2025, leaving important facilities vulnerable.

“Unsecured radiological materials at hospitals across the country could be used by terrorists to build a dirty bomb that would have devastating social and economic consequences,” said Sen. Daniel K. Akaka (D-Hawaii), chairman of the Senate Homeland Security and Governmental Affairs subcommittee on oversight of government management.

“We must strengthen domestic radiological security requirements and accelerate efforts to secure all medical facilities with radiological materials,” Akaka said.

The GAO, the investigative arm of Congress, blamed delays on security requirements that are voluntary and too broad. The report also spelled out numerous examples of poor security.

In one instance, an unidentified big-city hospital kept cesium-137, a highly poisonous radioactive chemical, in a padlocked room, with the combination to the lock written on the door frame in a busy hallway.

At another hospital, the number of people with access to radio­active material could not be monitored because the computer program that tracked comings and goings didn’t count beyond 500.

Fourteen medical facilities refused to participate in the voluntary safeguards, the report said. Four of the unidentified facilities are in big cities.

“The longer it takes to implement the security upgrades, the greater the risk that potentially dangerous radiological sources remain unsecured and could be used as terrorist weapons,” the GAO said.

David McIntyre, a spokesman at the NRC, said in an e-mail that the agency and state regulators have imposed tougher security requirements on facilities with licenses for radiological material since the 2001 attacks. He also said the NRC and the NNSA cooperate in the voluntary security program.

The GAO findings underscore the larger problem of storage and tracking of nuclear materials around the world.