Presidential hopeful Howard Dean, who accuses President Bush of being weak on homeland security, was warned repeatedly as Vermont governor about security lapses at his state's nuclear power plant and was told the state was ill-prepared for a disaster at its most attractive terrorist target.

The warnings, according to documents obtained by The Associated Press, began in 1991 when a group of students were brought into a secure area of the Vermont Yankee nuclear plant without proper screening. On at least two occasions, a gun or mock terrorists passed undetected into the plant during security tests.

During Dean's final year in office in 2002, an audit concluded that despite a decade of repeated warnings of poor safety at Vermont Yankee, Dean's administration was poorly prepared for a nuclear disaster.

"The lack of funding and overarching coordination at the state level directly impacts the ability of the state, local and power plant planners to be adequately prepared for a real emergency at Vermont Yankee," state Auditor Elizabeth M. Ready wrote in a study issued five months after the Sept. 11 attacks.

Security was so lax at Vermont Yankee that in August 2001, the Nuclear Regulatory Commission staged a drill in which three mock terrorists gained access to the plant. The agency gave Vermont Yankee the worst security rating among the nation's 103 reactors.