The Ontario Building Code | Radon
(1) In addition to all other requirements, a buildingin the following designated areas shall be designed and constructed so that the annual average concentration of radon 222 does not exceed 200 Bq/m3of air and the annual average concentration of the short lived daughters of radon 222 does not exceed 0.02 working levels inside the building:
(a) the City of Elliot Lake in the Territorial District of Algoma,
(b) the Township of Faraday in the County of Hastings, and
(c) the geographic Township of Hyman in the Territorial District of Sudbury.