Washington ? The United States remains “dangerously vulnerable” to chemical, biological and nuclear attacks seven years after 9/11, a forthcoming independent study concludes. And a House Democrats’ report says the Bush administration has missed one opportunity after another to improve the nation’s security.

The recent political rupture between Russia and the U.S. only makes matters worse, said Lee Hamilton, the former Indiana Democratic congressman who helped lead the 9/11 Commission and now chairs the independent group’s latest study.

Efforts to reduce access to nuclear technology and bomb-making materials have slowed, thousands of U.S. chemical plants remain unprotected, and the U.S. government continues to oppose strengthening an international treaty to prevent bioterrorism, according to the report produced by the bipartisan Partnership for a Secure America.