What Is Radon Gas? A Chicago Homeowner's Complete Guide

What is Radon?

Radon is a radioactive noble gas that occurs naturally as uranium in soil and rock breaks down. It is colorless, odorless, and tasteless, making detection impossible without specialized tools.

Health Risks of Radon

The U.S. Environmental Protection Agency (EPA) categorizes radon as a Group A human carcinogen. It is identified as the second-leading cause of lung cancer in the United States, accounting for about 21,000 deaths each year.

Why Chicago and Northern Illinois Are High-Risk Zones

Illinois sits in EPA Radon Zone 1 — the highest-risk classification — for the majority of its counties, including Cook, DuPage, Will, Kane, Lake, and McHenry counties. The glacially deposited soils throughout the Chicago metropolitan area contain elevated concentrations of uranium-bearing minerals, which continuously produce radon gas.

As radon migrates upward through soil, it infiltrates buildings through:

• Foundation cracks and construction joints

• Gaps around service pipes and utility penetrations

• Hollow-block masonry walls

• Exposed soil in crawl spaces

• Sump pit openings and floor drains

  
  

Because Chicago homes spend five to six months per year tightly sealed against winter temperatures, radon concentrations build to dangerous levels without adequate ventilation.

EPA Action Level and Illinois Standards

The EPA recommends mitigation when indoor radon levels reach or exceed

4 picocuries per liter (pCi/L).

Illinois also regulates the radon industry under the Illinois Radon Awareness Act (ILCS 420/7.9), requiring all radon measurement and mitigation professionals to be licensed by the Illinois Emergency Management Agency (IEMA). At US Environmental, all of our radon professionals hold current IEMA licenses and follow National Radon Proficiency Program (NRPP) and National Radon Safety Board (NRSB) protocols.

Frequently Asked Questions

Short-term professional testing takes 48–96 hours. Long-term testing runs 90 days or more.

Does my Chicago home automatically have high radon?

Not necessarily, but the regional geology puts all northern Illinois homes at elevated risk. Testing is the only way to know.

Who must be licensed to test for radon in Illinois?

Illinois requires IEMA licensure for all professionals offering radon measurement services.

SCHEDULE TEST NOW

Contact US Environmental today to schedule a professional radon test for your Chicago-area home. Our licensed specialists serve Cook, DuPage, Will, Kane, Lake, and McHenry counties.