The threat of radiation not only found around nuclear reactors. Sources of radioactive compounds exist everywhere, including foundation cracks that can release radon gas and a trigger lung cancer after smoking most number 2.

Radon is a radioactive chemical element with the symbol Rn, atomic number 86 and half-life of 3.8 days. This element includes the noble gases because they do not react with other elements and their existence can not be detected directly by the senses.

The threat of danger is no higher than cigarette smoke, but the U.S. Environmental Protection Agency (EPA) noted 21,000 people per year died from lung cancer induced by radon gas. That is, radon is the second largest cause of lung cancer after smoking, so should not be underestimated.

“Radon gas is colorless, odorless and not directly trigger the symptoms. You could just breathe it in large quantities without ever realized before,” said Kristy Miller of the EPA, as quoted by HealthDay.

Home foundation cracks are one source of radon gas that needs to watch out for in your neighborhood. Stone and other material originating within the earth element radium (Ra), which will break down into radon gas if you have cracks or breakage.

Because not detected by the senses, the existence of this gas can only be known with a special tool. EPA recommends routine inspection conducted on older houses or damaged, for example from the cracks in the walls and foundations.

According to Miller, radon gas at levels four picocurry / liter (pCi / L) can still be tolerated by humans without causing negative effects. But if it exceed 4 pCi / L then the house must be renovated to close the crack rocks that allow for the release of radon gas.