Granite countertops, like many natural stones, contain trace amounts of radioactive elements such as uranium, thorium, and potassium. These elements emit low levels of ionizing radiation in the form of gamma rays and, to a lesser extent, radon gas. However, the levels of radiation emitted by granite countertops are generally considered to be very low and not significant enough to pose a health risk to humans.
The United States Environmental Protection Agency (EPA) and other health organizations have conducted studies on granite countertops and concluded that the levels of radiation they emit are within safe limits. The radiation exposure from granite countertops is typically much lower than what people are exposed to from natural background radiation, such as cosmic rays from space and radon gas that can be present in the air.
In the vast majority of cases, granite countertops do not pose a cancer risk due to radiation exposure. However, if you are concerned about radiation levels, especially if you live in an area with high radon levels, you can have your home tested for radon to ensure that it is within safe limits. Additionally, proper ventilation in homes can help mitigate any potential radon concerns. If you have specific health concerns or questions, it's best to consult with a health professional or radiation expert for personalized advice.