HERMISTON -- Test results came back negative for two civilian guards who were examined for exposure to sarin nerve agent at the Umatilla Chemical Depot.

While the results released Tuesday have alleviated concerns about the guards' health, state officials are examining why it took so long to receive the information and notify the community.

Groups like the Oregon Department of Environmental Quality and the Chemical Demilitarization Program also are looking to ensure notification delays won't happen in the future.

Dennis Murphey, administrator for the Environmental Quality Department, said the test results were a relief. "Those were the results we were all hoping to see," he said.

Mary Binder, spokeswoman for the depot, said the urine samples that had been sent to Aberdeen, Md., did not show nerve agent metabolites, which would have been present had the two men been exposed to sarin.

The urine samples were taken Oct. 18, three days after the potential exposure and after blood tests showed possible exposure to the deadly nerve agent.

On Oct. 15, two civilian guards employed by the Army were checking motors on the filter systems connected to the storage bunkers about 11 p.m. at the depot, 35 miles south of the Tri-Cities. Guards check the motors every hour by driving by the filters at the rear of the storage igloos, rolling down a window and verifying the motor is running by sound.

The depot stores 220,604 munitions and containers filled with 7.4 million pounds of deadly nerve and mustard agents.

The guards, whose names have not been released, were checking an igloo containing munitions filled with GB sarin nerve agent that have previously leaked. The two men noticed a metallic taste in their mouths and a sulfuric rotten egg smell. One also developed a runny nose.

Of the three symptoms, only a runny nose is a potential symptom of sarin exposure. The gas is odorless.

As a precaution, blood was drawn from the two guards, but the results were not ready until three days later. It was another day before depot Commander Lt. Col. David "Doc" Holliday notified groups like Umatilla and Morrow counties' emergency management and the Environmental Quality Department.

The initial blood tests showed the guards had depressed levels of cholinesterase which is one indication of exposure to a nerve agent. A second set of blood draws three days later showed the levels had returned to normal.

Binder said Tuesday that cholinesterase levels can be affected by stress or pesticides and that doctors focused mostly on symptoms when they were looking for nerve agent exposure.

Administrators still are looking at what caused the smell and metallic taste, she said. "They're checking everything from the vehicle itself, possibly the catalytic converter," to what was going on in the surrounding area, she said.

Both guards, who had been restricted from working in areas where they might be required to wear gas masks, were relieved of that restriction late last week, Binder said.

She had not heard of any complaints from the union representing the guards. Union officials could not be reached for comment.

Officials also are looking at why the tests and notification took so long. On Thursday, Holliday faced harsh criticism and more than an hour of questioning about the incident at a citizens advisory group meeting.

No changes had been made to the procedure of how officials would handle similar situations in the future, but it was something administrators continued to work on, Binder said.

But Murphey's department still had some questions. It had people looking at how the days that lapsed between the incident and the second blood draw and urine samples might have affected the results.

Murphey's department also was looking at adding a requirement to the storage facility's permit that would require quicker notification of similar incidences in the future.