The Palo Alto City Council voted unanimously Monday to put a measure on the Nov. 4 ballot to take fluoride, a cavity-fighting chemical, out of the city’s water. Councilman Bern Beecham made the motion.

A monthslong initiative headed by Palo Alto psychologist Susan Willis gathered enough valid signatures to put the issue up for a public vote, but a 1995 state law requiring Palo Alto and other cities to fluoridate their water had put the initiative’s legality into question.

“We should be able to vote on whether to continue putting into our water an unapproved chemical with an excess of contaminants,” said Jeff Green, with Citizens for Safe Drinking Water, a national organization that fights fluoridation. “Many other cities have taken positions against fluoridation and have not been preempted by state law.”