fast facts 

Indoor Air Quality - 

 Radon 

September 2008 

Office of Compliance 

advancing safety, health, and workplace rights in the legislative branch 

www.compliance.gov 

indoor levels of radon by state and 

country. 

There are several common units of 

measurement for the amount of 

radioactivity in a substance. The 

terms “REM” or “Sieverts” are 

often used. But in the case of radon, professionals will use picocuries per liter of air (piCi/L) as 

the unit of measurement when 

talking about the concentration of 

radon gas in air or water. 

When radon decays, it emits an 

alpha particle which travels less 

than 10 centimeters (1⁄2 inch) in air 

and about 60 micrometers in tissue. However, as it travels, it ionizes many other molecules until it 

loses its energy. Fortunately, alpha particles can easily be blocked 

by the layer of dead skin that covers our bodies. However, if radon 

gas gets into the body and decays, 

live cells have fewer defenses and 

can be killed or suffer cellular 

changes that could lead to cancer. 

People can be exposed to radon 

gas by inhaling it either from the 

air or as it is released from running 

water, perhaps from a bathroom 

shower or kitchen faucet. 

Several agencies have occupational and public health standards 

for exposure to radon gas. The Occupational Safety and Health Administration (OSHA) has a workplace exposure limit of 100 piCi/L 

for 40-hours over 7 consecutive 

work days (29 CFR 1910.1096(c)

(1)). The EPA has set a standard 

for radon gas in the air in homes at 

4 piCi/L and in water at 300 piCi/L. 

In the workplace, industrial hygienists might use an Alpha Track to 

conduct short- and long-term analyses of radon gas levels. In the 

home, similar devices might be employed by investigators. Homeowners can purchase commerciallyavailable test canisters. These are 

placed in various areas of the building or home, usually one on each 

level. After the conclusion of the 

sampling period, the canisters are 

sent to a laboratory for analysis. A 

report comes back within a week or 

two. If radon levels exceed EPA 

guidelines, remedial actions such as 

increasing ventilation, sealing 

cracks and seams in foundations 

and floor slabs, and sub-slab ventiFigure 1: Decay products and vapor pathways of radon lation systems are sometimes used. 

into homes and buildings. 

Figure 2: Alpha particles have limited penetration. 

Radon, a decay product of uranium, 

is a naturally occurring gas that seeps 

out of rock and soil. In areas where it 

is present, radon gas will seep into 

buildings, exposing occupants and 

visitors and can pose significant 

health issues. Approximately 20,000 

people die from lung cancer as a result of residential and occupational 

exposure to radon gas each year. 

Uranium, which is naturally radioactive, is found in rock in various locations around the world. Whether or 

not an area of the country has the potential to have measurable levels of 

radon is a function of local geology. 

The United States Environmental 

Protection Agency (EPA) periodically publishes updated maps of the 

location of uranium-bearing rocks 

and sediments and the likelihood of 

finding measurable levels of radon 

inside buildings built over these formations. This website (http://www. 

epa.gov/iaq/whereyoulive.html) 

can provide you with the estimated 
fast stats 

• Radon is a naturally occurring radioactive gas that you cannot see, smell, or taste. 

• Radon is the leading cause of lung cancer for non-smokers and claims 20,000 lives annually. 

• The U.S. Surgeon General and the EPA recommend that all homes be tested for radon. 

• You can purchase radon test kits and test your home yourself. To find a qualified tester or mitigation contractor, 

contact your state radon office. 

• The OOC has tested underground facilities in the Legislative Branch Campus and has found radon levels well 

below both the EPA guidelines and the OSHA exposure standards. 

 

 

This information does not constitute advice or an official ruling of the Office of Compliance or the Board of 

Directors and is intended for educational purposes only. For further information or comments concerning this 

Fast Facts, please refer to the Congressional Accountability Act (2 U.S.C. 1301 et seq.) and the regulations 

issued by the Board, or you may contact the Office of Compliance, 202-724-9249.

The Office of Compliance advances safety, 

health, and workplace rights in the U.S. 

Congress and the Legislative Branch. Established as an independent agency by the 

Congressional Accountability Act of 1995, 

the Office educates employees and employing offices about their rights and responsibilities under the Act, provides an impartial 

dispute resolution process, and investigates 

and remedies violations of the Act. 

If you have any questions, please do not 

hesitate to contact the Office of Compliance: 

Room LA 200, John Adams Building 

110 Second Street, SE 

Washington, D.C. 20540 

t/ 202-724-9250 

tdd/ 202-426-1912 

Peter Ames Eveleth f/ 202-426-1913 

General Counsel 

Mary-Margaret Smith 

Editor Download the entire Fast Facts suite at http://www.compliance.gov 

The Office of Compliance has tested underground facilities in the Legislative Branch Campus and has found 

radon levels well below both the EPA guidelines and the 

OSHA exposure standards. We join with the EPA and 

the Surgeon General of the United States in strongly 

suggesting that each employee have his or her home 

tested. 

 

 

For further information on radon and how you can 

protect yourself and your family, please visit this website: http://www.epa.gov/radon/. Figure 3: Commercially available 

home radon test kits. 

Figure 4: Radon mitigation.