Answer to Question #6969 Submitted to "Ask the Experts"

Category: Environmental and Background Radiation — Granite and Stone Countertops

The following question was answered by an expert in the appropriate field:

Q
If you have newly installed granite countertops and a radiation detector sounds off when you walk by, does that mean the exposure is harmful to humans or animals? We are trying to understand if we need to have these countertops removed, but the manufacturer will not reply.
A

Radioactive elements including uranium, radium, thorium, and a radioactive isotope of potassium are naturally present in our world and are found throughout the environment to a greater or lesser degree in all rocks and soils. Although, typically, granites contain more naturally occurring radioactivity than do other types of rocks such as sandstones, granites contain only a few parts per million of such naturally occurring radioelements as uranium, thorium, and radium. While this is sufficient to produce a reading on a sensitive radiation detection instrument, the levels of radiation produced by the natural radioactivity in these granites is well below the level that would result in any harm. So you need not worry about any risk to your health and there is no need to remove the countertops. However, you may wish to check with your state radiation control office, which can give you more information pertaining to your specific situation.

Ron Kathren, CHP

Answer posted on 11 January 2008. The information posted on this web page is intended as general reference information only. Specific facts and circumstances may affect the applicability of concepts, materials, and information described herein. The information provided is not a substitute for professional advice and should not be relied upon in the absence of such professional advice. To the best of our knowledge, answers are correct at the time they are posted. Be advised that over time, requirements could change, new data could be made available, and Internet links could change, affecting the correctness of the answers. Answers are the professional opinions of the expert responding to each question; they do not necessarily represent the position of the Health Physics Society.