OAK RIDGE - A security test last summer at the Y-12 nuclear weapons plant may have been "compromised" because some plant police had advance information on the exercise, according to a federal report released Monday.

The Oak Ridge test results were "tainted and unreliable," the U.S. Department of Energy's Inspector General concluded.

A guard mans a gate at the Y-12 nuclear weapons plant in Oak Ridge, Tenn., Sept. 11, 2001. Guards cheated in a mock terrorist drill at the plant last summer, and apparently have been doing so since the 1980s, the Energy Department's inspector general says in a report released Monday, Jan. 26, 2004. Investigators found security personnel learned in advance which walls would be breached and which buildings would be targeted, and planned accordingly. Then they used improperly inserted batteries, mud or Vaseline to befuddled the body sensors that simulate fatal gunshots. (Photo/Wade Payne)

Furthermore, investigators said they interviewed "several current and former protective force personnel" who detailed improprieties in Y-12's security tests dating back to the mid-1980s. Guards were told, in some instances, what buildings were to be attacked during mock incursions and whether there would be diversionary tactics used in an exercise.

The IG report is the latest blow to the image of Oak Ridge security, coming on the heels of a scathing assessment by a government watchdog group. The Project On Government Oversight said that Y-12 security forces failed to protect the plant's nuclear assets during a December exercise - raising grave questions about their ability to counter a terrorist attack.

BWXT Y-12, which manages the plant for the federal government, last week named a new security director. The National Nuclear Security Administration, a DOE sub-unit that oversees the weapons operation, also changed security directors in Oak Ridge. Neither BWXT nor NNSA would say whether the leadership changes were results of the security problems.

Steven Wyatt, a spokesman in DOE's Oak Ridge office, declined comment Monday on the IG report. However, the document said that federal officials concurred with findings and were taking corrective actions.

Bill Brumley, the Oak Ridge chief of the NNSA, last year told the News Sentinel that the results of the summer exercise were considered too good to be true, and that he asked the Inspector General to look into the matter.

Eyebrows were raised when the Y-12 protective force won all four of the test exercises in the June security review. Computer simulations conducted before that review had predicted Y-12 police "would decisively lose two of the four scenarios."

While some guards interviewed by the IG said they did not have advance information on the security tests, investigators concluded there was enough evidence to taint the results.

"We found that shortly before the test, two participating protective force personnel were permitted to view the computer simulations of the four scenarios," the IG report said. "We concluded that this action was improper, since it had the potential to adversely impact the realism of the performance test and outcome. In short, the test results were tainted and should not, in our judgment, be relied upon."

During the Oak Ridge inspection, the team interviewed more than 30 current or former security police officers. Investigators said they received information on a "pattern of actions" over an extended period of time that may have skewed the realism of Y-12 security exercises and affected the performance results.

"We found their assertions to be credible and compelling," investigators said in the report.

The Inspector General report also heard allegations that Y-12 guards tampered with laser-based systems used to identify guards disabled during the simulated terrorist exercise. Investigators said some guards obstructed the sensors by applying tape, mud or petroleum jelly to the surface.

Among other allegations: