Air Testing

Radon Testing


What is Radon?

Radon is a naturally occurring gas that is odorless, colorless and tasteless. It comes from the natural decay of uranium that is found in nearly all soils in the United States. Radon gas is in the air, both inside and outside. When people are outside, the radon levels are so low they pose no health threat. However, levels must be monitored in public buildings.


How We Test for Radon

The Health Department, with assistance of MNPS maintenance staff, tests all schools and other occupied buildings using a test placed in schools during weekends. The EPA recommends action be taken to reduce levels if the concentration of radon is 4 pCi/L (picocuries per liter) or greater but does not suggest avoiding these areas while efforts are underway to reduce the levels.

According to the Metro Health Department Regulation 9, a reading >4Pci/L up to 20Pci/L requires a confirmatory test over a 9-month school year within the next two years. Then if the confirmatory test is still greater than 4Pci/L, the district has a year to submit a plan to reduce it and two years to implement the plan.

MNPS will take additional precautionary steps over and above those found in Regulation 9. In conjunction with the retesting that is required by Regulation 9, MNPS will review and correct any malfunctions or inefficiencies to the mechanical systems of the buildings where actionable levels of Radon are noted in initial tests, ahead of any required re-testing.

This may include adjustments or corrections to cracks or voids in the floor system that need resealed as well. We will continue the monitoring and retesting as prescribed by the Health department in addition to the early investigation and mitigation by MNPS. Where retesting continues to result in actionable levels of radon in a specific area, we may install passive radon mitigation systems followed by an active system where necessary. Where actionable levels are initially noted by the Health Department tests and follow up tests prove levels have fallen below those levels with no need to pursue other options, we will retest those areas in the time period prescribed by Regulation 9 as if they were still at actionable levels as a double-check of the test results.


Included on this page are the testing results for MNPS schools, including those that have between one and three rooms that exceeded the action level of 4pCi/L when tested. Because radon readings can be affected by numerous factors, the district re-tests these schools using a 90-day day test that will provide a more accurate reading of radon level.