The city's municipal building was locked down for about 1 1/2 hours Friday when a woman brought a backpack with a white substance on it into the police department's reception area on the Second Street level.
Authorities said the white, grainy substance tested negative for anthrax.
They asked anyone who discovers a suspicious substance to not move it, but call 911 immediately.
According to Deputy Police Chief Lawrence A. Wallace, the woman, who was not identified, arrived in the reception area about 10:30 a.m. and asked someone to look at the substance.
"That immediately caused a problem at City Hall. We had to lock down City Hall due to our protocol, because of the ventilation system," Wallace said. "The HazMat Team was called (in). It took a while, but eventually the substance was tested in the field and it proved to be negative."
Michael Vendette, who coordinates both the Chautauqua County Hazardous Materials Team and its Counter-Terrorism Task Force, said there was not a large quantity of the powdery material.
"We went in and we secured that bag, and we decontaminated the reception area as a precaution. Then we moved to her vehicle," Vendette said. "We could not find the source (of) the powder. We really did not find any major amount of powder, just some suspicious looking powder in the back (of the car)."
The municipal building includes Police Headquarters and city Fire Station One. Wallace said the city was covered despite the lock down, during which no one could enter or leave the building.
"The fire department has other fire stations so they were able to handle that, and . . . of course, the police cars were on the road already, so, those cars just took double duty," he said.
Vendette said there would be further testing of the substance.
Wallace urged residents not to overreact if they discover a suspicious substance, but to minimize their exposure and call authorities.
No one was hurt in the incident, and no charges were placed.