Despite the best anti-terrorism planning, soldiers, civilian guards, guns, barricades and barbed wire, bases storing U.S. chemical weapons are still "potentially vulnerable" to terrorist attacks, a new government study says.

Of course, the base that stores the most chemical weapons in the nation is Utah's Tooele Army Depot. It contains 42 percent of the U.S. stockpile.But questions about whether such bases can deter terrorists were raised when the U.S. General Accounting Office, a research arm of Congress, recently reviewed the physical security at bases with chemical arms.

While an unclassified version of its report said bases generally comply with Army security standards, it added, "All nine of the sites we visited were potentially vulnerable to aerial attack. Also, key security officials at four sites believe that their sites are vulnerable to ground attack."

The Tooele depot was among the bases visited, but the report did not say whether it is one of the sites considered vulnerable to ground attack. The Army also declined comment on that.

However, Army Materiel Command spokesman Greg Mahall said, "Security plans for the chemical sites are far-reaching and extensive."There are physical barriers and manpower-intensive measures in effect. They are designed to stop any anticipated threat. Even though the commanders are expressing concern at this time, there is no intelligence agency projecting any threat (from terrorists)."

Officials at Tooele Army Depot referred all inquiries on the topic to the Army Materiel Command at the Pentagon.

Mahall added that while the report says base security officers feel their facilities may be vulnerable to attack, he said they constantly postulate worst-case scenarios to try to protect against them.

"They prepare for the worst, and we feel the measures there address the threats," he said.

Details of exactly why bases are considered vulnerable were not released in the unclassified version of the GAO report. They were, presumably, included in the classified version prepared for the House and Senate government operations committees.

But the unclassified version gives some basic information.

"The potential for a successful terrorist action appears to be greater if the intent is to damage or destroy the chemicals rather than to steal or divert them," the GAO report said.

It also quoted 1985 memorandums from the assistant secretary of defense for atomic energy saying the consequences of a chemical incident likely would not be devastating - but could be.

"He stated that causing a few one-ton containers to split open and leak could cause only a few casualties, maybe none. He also stated that the potential consequences of destroying a chemical storage igloo were less severe than they would be in the case of nuclear weapons.

"But the local effects of a downwind hazard could be devastating."

The report also adds, "Although the sites are potentially vulnerable to terrorist attack, no chemical sabotage or diversion attempts have been made at the storage sites in the past five years. Further, (the Defense Department) postulates that the threat of potential adversaries attacking a . . . chemical weapons facility is low."

The report also outlined a few other problems it found with some security measures at some bases. They include:

- Formal site vulnerability assessment were either not completed or conducted properly. Mahall said a new assessment for Tooele was completed in February. He added that assessments have also recently been completed for all other chemical storage sites.

- "Inadequate assurances exist that civilian security guards can perform in emergencies because . . . their physical fitness has not been tested against specific agility standards," the report said.

Mahall said the Army Materiel Command is putting into effect new administrative procedures to require medical evaluations and agility testing for guards.

He said it will require "such things as doing so many push-ups and sit-ups, and being able to run over distance." He said guards at chemical storage sites "are of all age ranges" and new procedures take that into consideration.

- The GAO also said guards work "excessive overtime hours." Mahall said no overtime work is mandatory. Therefore, the Army feels guards will volunteer only if they are alert enough and feel well enough to do the job.

- The GAO also said vehicles used by many guards were old and often broken down, which hampers their effectiveness. Mahall said the Army recently allowed bases to lease cars from the General Services Administration, which should ensure working cars are always available.

"Tooele has six to 10 leased vehicles," he said. "So once they hit a certain age, they can be turned back in."