We tend to think that naturally occurring substances are either good for us or at least not harmful. Sometimes neither of these viewpoints is correct. Radon gas may be one of the most extreme example of “natural” that’s quite capable of killing you. What Is Radon? Radon is a radioactive gas that forms when the Earth's crust traps gas from the atmosphere. According to government analysis, radon can be found in every home to some extent. What matters is how much radon is there if it’s found in your house. Some geographical regions have radon-laden soil and rocks, and this can lead to high enough indoor concentrations to cause avoidable lung cancers, while other areas don’t have harmful levels at all. Testing is the only way to know for sure if radon levels in your home are high enough to warrant remedial action. Colorless, odorless, and tasteless, radioactive radon gas is the leading cause of lung cancer in non-smokers, and the second leading cause of lung cancer overall. Anything over 200 Becquerels per cubic meter (Bq/m3) is considered dangerous, and levels can be reduced to less than 100 Bq/m3 with the right ventilation equipment. Even if your neighbour’s home has been tested and found safe without having a radon reduction system in place, that doesn’t mean that your home is safe, too. Indoor radon concentrations can be affected by many things and can vary tremendously from one house to the next.