Where Does the Radiation Come From?

• Radon, an elemental undetectable gas, is released when deposits of uranium decay. Uranium is also an element found in many natural substances, including granite, concrete, and even soil. Radon is odorless and colorless and creates radiation that is often safely used in processes such as medical x-rays. However, radiation in large amounts can be dangerous.
  
  

Why is Radon in Concrete?

• Since it is found in natural materials, it is understandable that radon is found in granite, a natural type of rock. However, you may be confused as to why radon is found in concrete. Many people are unsure what concrete really is. Concrete is a mixture of cement powder, fine aggregate, and coarse aggregate. The fine aggregate used is very commonly clean sand, and the coarse aggregate is usually gravel. Both of these contain some natural uranium and, thus, may produce radon gas.
  
  

Dangers of Radon

• Large doses of radon gas can do a great deal of damage. In its original form, it can harm and even kill the cells of the lungs, making it difficult to breathe. It can even cause lung cancer. In addition, radon gas decomposes into two different elements once inside the human body: polonium and lead. Most people are familiar with the dangers associated with lead poisoning, which include illness and even brain damage.
  
  

Amount of Radon in Concrete

• According to the Environmental Protection Agency (EPA), contained concrete structures, such as counters, release very little radon. There have been cases in which concrete caused radon levels to be within the "danger zone" of 4.0 pCi/L. However, these are usually commercial buildings with concrete ceilings, floors, and other exterior structures. The general consensus among scientists seems to be that counters, whether they are made of granite, concrete, or another natural material, are not a dangerous source of radon or radiation.
  
  

The Real Danger

• Because of unequal air pressure, your home can create a vacuum around the foundation. This vacuum gathers air from the soil near the foundation, which often contains high levels of radon. Sometimes, groundwater supplies can even become contaminated with radon-producing soil. These sources of radon are much more alarming than the trace amounts found in concrete counters.
  
  You should have a radon detector in your home. It may be just as important as a smoke alarm or carbon monoxide detector. However, unless and until your concrete counters cause the alarm to sound, they are most likely quite safe.
  
  Seal your concrete counters with masonry sealant when they are installed, and then reseal them once a year. This will prevent the porous material from harboring bacterial growth, which is far more likely to be the reason that your concrete counters make you ill.