General Radon Information

South Dakota specific radon and radon level information can be found throughout this site. You will be able to find information about certified radon inspectors in South Dakota, as well as detailed radon level information for every county in South Dakota.

Radon - You can't see it. You can't smell it. You can't taste it... While most people are aware that air pollution can be hazardous to their health, many do not know that the air they breathe inside their own homes could be killing them. Millions of homes and buildings contain high levels of radon gas. Many do not even know it is present. When radon decays and is inhaled into the lungs, it releases energy that can damage the DNA in sensitive lung tissue and lead to lung cancer. In fact, prolonged exposure to high levels of radon is the second leading cause of lung cancer in the United States, contributing to between 7,000 and 30,000 lung cancer deaths each year. Smokers are at higher risk of developing radon-induced lung cancer.

Since the late 1980's, radon levels have been measured throughout the state of South Dakota. This data has been collected and compared to geological formations to yield zone classifications, which are based upon being able to predict the likelihood of finding certain ranges of radon concentrations when conducting short-term radon measurements. The eastern portion of the state is Zone 1 (Highest Potential - greater than 4 pCi/L) with the balance being Zone 2 (Moderate Potential - from 2 to 4 pCi/L). There are no Zone 3 (Low Potential - less than 2 pCi/L) areas in South Dakota.

Radon levels are often related to geography. Much of North and South Dakota, western and southern Minnesota, and northern Iowa are underlain by deposits of the Des Moines, James, and Red River glacial lobes. Included within this region are clay and silt deposits of glacial lakes Agassiz, Souris, Dakota, and Devil's Lake, which generate some of the highest radon levels in the area. Des Moines lobe tills are silty clays and clays derived from the Pierre Shale and from Tertiary sandstones and shales which have relatively high concentrations of uranium and high radon emanating power. The lower part of the Pierre Shale has an overall higher uranium content than the upper part, and locally contains black shales such as the Sharon Springs Member. Glacial deposits of the Des Moines and James lobes generate high (> 4 pCi/L) average indoor radon concentrations, have high proportions of homes with elevated indoor radon levels, and have high radon potential.

Southwestern North Dakota and western South Dakota are underlain by unglaciated Tertiary and Cretaceous sandstones, siltstones, and shales, some of which include uraniferous coals and carbonaceous shales. Carbonaceous shales, uranium-bearing coals, and ash clay beds in Tertiary sedimentary units of southwestern North Dakota and western South Dakota, including the Fort Union Formation (and its equivalents) and the White River Group, generate locally very high radon levels, and have overall moderate to high radon potential. Uranium deposits occur locally in Paleozoic and Mesozoic marine sedimentary rocks surrounding the Black Hills, particularly in sandstones of the Lower Cretaceous Inyan Kara Group in the southern Black Hills. Granites in the core of the Black Hills have moderate radon potential.

Radon is harmlessly dispersed in outdoor air, but when trapped in buildings can increase the risk of lung cancer, especially at elevated levels. It typically enters a home the same way air and other soil gases enter the home, through cracks in the foundation, floor or walls, hollow-block walls, and openings around pipes, sump pumps, and floor drains. It can also be present in some construction materials and in water from underground sources including private wells. Any home, regardless of age, energy-efficiency, or foundation type, could have a radon problem. The only way to know whether or not a particular home has a problem is to test THAT home.

If your home has high radon levels, there are ways to reduce the concentrations. Even very high levels can be reduced to acceptable levels. There are several methods that can be used to lower radon levels in your home. Some techniques prevent radon from entering your home while others reduce radon levels after it has entered. EPA generally recommends methods which prevent the entry of radon.

One method that prevents the entry of radon into your home is called active soil depressurization. This system consists of pvc pipe connected to the soil either through a hole in the slab, a sump lid connection or beneath a plastic sheet in a crawl space. Attached to the pipe is a quiet, continuously operating fan that discharges the radon to a safe location outside of the home.

* Average installation cost: $1,200

* Average operating cost in South Dakota:$3.00/month

* Expected life span of fan: 11 years

* Fan replacement cost: $145 - $300

For more information on radon or request for a speaker to talk about radon contact Barb Regynski (email DENRINTERNET@state.sd.us ) at (605)773-3151.

1-800 Numbers

* South Dakota Radon Information Line 1-800-GET-DENR (1-800-438-3367)

* National Radon Information Line 1-800-SOS-RADON (1-800-767-7236)

* Radon FIX-IT Program 1-800-644-6999