Radon is a colourless, odourless and tasteless radioactive gas that is produced by the breakdown of uranium in soil and rock. Radon is present in outdoor air at low concentrations and is harmless. However, in an enclosed house, radon can build up and create a long-term health risk to occupants. The concentration of radon within a home depends on the radon concentration in the soil below the house, the pressurization of the home (i.e. depressurization pulls radon in through foundation cracks), and the house ventilation rate. Air sealing and insulation weatherization work in a basement or crawlspace (e.g. sealing foundation cracks and gaps) can help reduce radon concentration, though at the same time, air sealing work can lead to a more airtight home that is then prone to more depressurization and poor ventilation (unless addressed). Radon is more of a concern for homes east of the Coast Mountains in the interior of B.C., than it is for homes in coastal B.C. When performing weatherization work in homes within potentially affected areas, basement and crawlspace sealing is recommended before attic or above-grade work. Where radon is a concern, testing should be performed and is relatively inexpensive. Further information can be found on the HealthLinkBC website www.healthlinkbc.ca.