EPA Standards of Practice
Action Based on Test Results
Action Level Guidance
Countries worldwide have adopted Action Levels for radon exposures. Most are similar to the 4 pCi/L (150 Bq/m3) action level recommended in the United States. The action level observed should comply with the guidance of the country, state, or other local jurisdiction of authority where the test is being conducted.
The following Action Level descriptions reflect guidance from the United States Environmental Protection Agency (EPA):
4 pCi/L or greater (150 Bq/m3)
Fix the home. The higher the radon concentration, the more quickly action should be taken to reduce the concentrations.
Below 4 pCi/L (< 150 Bq/m3)
Consider fixing the building if test results indicate that radon concentrations are greater than
half the action level, such as between 2 and 4 pCi/L (75 and 150 Bq/m3).
half the action level, such as between 2 and 4 pCi/L (75 and 150 Bq/m3).
Action Level guidance is based on the U.S. Environmental Protection Agency’s national radon
program, which recommends mitigation at 4.0 pCi/L (150 Bq/m³). Levels below 4.0 pCi/L do not
require mitigation under U.S.
program, which recommends mitigation at 4.0 pCi/L (150 Bq/m³). Levels below 4.0 pCi/L do not
require mitigation under U.S.