What is radon?

Radon is a naturally-occurring gas produced by the radioactive decay of the element radium. Radon itself is radioactive because it also decays to form the element polonium. Polonium is also radioactive - it is this element, which is produced by radon in the air and in people's lungs, that can hurt lung tissue and cause lung cancer.

Radon is ubiquitous (usually in small amounts) in rock and soil and can be carried in water, air, and in natural gas. Some rock types have the potential to produce higher-than-average amounts of radon gas.

As of the late 1990s, USGS research on radon has mostly been limited to its presence in groundwater. The Environmental Protection Agency (EPA) is the best starting point for information about air quality and radon in buildings.

Related Content

Filter Total Items: 1

Should I be concerned about radon in my house?

You can get an idea as to how concerned you should be about radon in your house by learning about the geology of the site and its radon potential. If your house is in an area with a high potential for radon, then chances are that your house may have an indoor radon problem. However, the way a house is built can increase the risk - so even in areas...
Filter Total Items: 3
Date published: May 11, 2017

High Levels of Radon Found in Some Wells Across Pennsylvania

A new U.S. Geological Survey study has discovered high levels of radon in wells across certain areas of Pennsylvania.

Date published: March 6, 2017

USGS Finds Elevated Levels of Arsenic, Radon, Methane in Some Private Wells in Lycoming County, Pennsylvania

Tests of 75 private drinking water wells in Lycoming County, in north-central Pennsylvania, found water from most of the sampled wells contained concentrations of radon that exceeded a proposed, nonbinding health standard for drinking water. Smaller percentages of the wells contained concentrations of arsenic or methane that exceed existing drinking water standards.

Date published: June 12, 2001

Radon in Blue Ridge Ground Water Among Highest In Nation

Radon concentrations in ground water from homeowners’ wells in the Blue Ridge area of the New River watershed, in parts of North Carolina and Virginia, were among the highest measured in the nation in a new report from the U.S. Geological Survey. Radon is a radioactive gas, and radon in air is the second leading cause of lung cancer.

Filter Total Items: 2
Larger image shows a USGS scientist standing in the lab, while the inset shows the outside of the lab
November 30, 2000

The New Lab

USGS physical scientist Lee-Gray Boze and research engineer Junbong Jang depressurize one of the test chambers that make up the Pressure Core Characterization Tools in HyPrCAL, the new USGS pressure core analysis facility.  Inset photograph shows the new laboratory in Woods Hole, Massachusetts. Credit: USGS.

map showing different colors for amounts of radon in groundwater in NY wells

Radon samples in New York groundwater wells

Radon samples in New York groundwater wells