The Fairfield Health Department announced the results for soil samples taken at eight public schools in town.
Five were deemed safe, but three sites showed levels of either arsenic or another toxin that exceeded criteria.
Those sites include Jennings Elementary School's soccer field, Mill Hill Elementary School's walkway to the lower playground and Riverfield Elementary School's baseball fields and playground area.
The state's Department of Health says the levels found at these three sites would not cause health effects, but the town will go ahead with remediation.
The report also says PCBs and asbestos were not detected at any of the locations tested.