(CNN) It was after midnight when police officer T. Grahn responded to a call about a makeshift barricade on a street in Arvada, Colorado, a community just northwest of Denver.

Street signs had been pulled out of the ground, and plastic wrap was strung across the road. Grahn noticed a small plastic bottle that looked like trash. Just then someone yelled, "Hey, asshole," and ran away.

Dominic Battista, one of the people who called the police about the roadblock, was helping Grahn clear the road when someone threw a plastic bottle about 15 yards away from them. The bottle "started shrinking and releasing 'a ton' of white colored smoke," according to the Jefferson County arrest affidavit.

Grahn walked toward the smoke bomb, began feeling nauseated, "and the next thing he remembered was waking up to APD officers removing his uniform and attempting to provide him medical assistance."

Battista felt "tightness and strain in his chest," and was treated, the affidavit said.

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