A 73-year-old woman has been released after being arrested on suspicion of administering an unknown noxious substance.
Emergency services were called to Stall Street in Bath on 29 July, after reports a woman had approached people with a plastic bag, who then fell ill.
One person went to hospital with breathing difficulties and itchy eyes, and was discharged hours later.
"It would appear this was an isolated incident and there was seemingly no intentional attempt to harm anybody," said Ch Insp Scott Hill from Avon and Somerset Police.
"Further enquiries will be carried out" by officers, after the woman was released under investigation.
At the time, a cordon was set up as police tried to determine the substance in the bag.
"In the early stages of this incident it was unclear what had happened," said Mr Hill.
"Emergency services have extensive plans for responding to such incidents and these were carried out to make sure treatment was available to anyone who needed it, and the wider public were kept safe.
"The arrested woman was questioned and property searched as part of our usual enquiries seeking to establish whether any crime had occurred.
"We are aware there has been speculative comments published, particularly on social media, suggesting this incident was a deliberate act seeking to cause harm and therefore wanted to be transparent about the status of our investigation," he added.
