Radon in Schools

What Schools Need to Know About Radon

Radon is a naturally occurring radioactive gas that has no color, smell or taste. Radon comes from the decay of uranium, which is a radioactive element found naturally in the earth’s crust. Over billions of years, uranium decays into radium, and eventually, radon. Radon is present in outdoor air, and radon levels can build up inside buildings.

Everyone is exposed to some radon in indoor and outdoor air. Breathing air with radon increases your risk of getting lung cancer. Your risk of getting lung cancer from radon depends on the level of radon in the air you breathe and for how long you have been exposed to it. If you smoke and are exposed to high levels of radon, your risk of getting lung cancer is especially high.

Unless you test for it, there is no way of knowing if radon is present in a building.

Why Test for Radon in Schools

For most school children and staff, the second-largest contributor to their radon exposure is likely to be their school. Vermont law required all schools to test for radon by June 30, 2025.
If a radon problem is found, the Health Department recommends schools take action to fix it.

Ongoing testing for radon is recommended. If the radon levels in a school building were low, retest the school every five years or whenever significant changes are made to the school’s structure or mechanical systems.

If the school has a mitigation system, test every two years to make sure the system is still working.

Schools can email the Health Department at radon@vermont.gov for questions about testing and mitigation.

Best Practices for Radon Testing

Hire a certified radon measurement professional that follows the ANSI/AARST standards for measuring radon in schools.
Notify parents, guardians, and school staff before and after you receive results, and post results to your school’s website.
Test on school days or with the HVAC system operating under occupied conditions, and ideally during cooler months when the heat is on.
If any of the radon results are elevated, evaluate radon levels during occupied versus non-occupied times of the day using continuous radon monitors that collect hourly measurements. Your certified radon measurement professional can help with this.
Retest your school every five years or whenever significant changes are made to the building’s structure or mechanical systems.

Best Practices for Fixing a Radon Problem

Hire a certified radon mitigation professional who follows the ANSI/AARST standards for measuring radon in schools.
Install a radon mitigation system or adjust HVAC settings if any results are at or above 4.0 pCi/L. Consider mitigating or adjusting HVAC settings if any results are at or above 2.0 pCi/L. Consult with an HVAC engineer before making adjustments to HVAC settings.
Notify parents, guardians, and school staff of your plan to fix the radon problem.
Test again to make sure your mitigation or HVAC adjustments fixed the radon problem.

Radon Testing FAQs

Is radon a problem in Vermont schools?

About 18% of Vermont schools that have tested for radon since 2005 have radon levels above the EPA action level of 4.0 pCi/L, with some as high as five times the action level. Testing is the only way to know what level of radon students and staff are exposed to.

Many factors contribute to radon entering a school building. Schools in nearby areas can have significantly different radon levels from one another. Here are some reasons why some schools have elevated radon levels and others do not:

Concentration of radon in the soil and permeability of the soil under the school
Structure and construction of the school building
Type, operation, and maintenance of the heating, ventilation and air-conditioning (HVAC) system

Who should test my school?

Hire a radon measurement professional certified by the National Radon Proficiency Program or the National Radon Safety Board. You’ll need to select a professional who is not employed by the Vermont Department of Health.

What should I look for in a certified measurement professional?

Choose a contractor to test for radon just as you would choose someone to do other building maintenance. It is wise to get more than one estimate, to ask for references, and to contact some of those references to ask if they are satisfied with the contractors' work.

When evaluating a contractor for school radon testing, ask the following questions:

Can you provide proof of your current certification with NRPP or NRSB?
Do you follow the ANSI/AARST standards for measuring radon in schools?
Do you have a history of measuring radon in schools or large buildings?
Can you do continuous radon monitoring?
Will you help interpret our results and offer recommendations?

My school building or HVAC system is being renovated, should I wait to test?

Yes. Changes to a building’s structure or mechanical systems can influence radon levels. Wait to test for radon until your renovations are complete and your HVAC system has been commissioned.

How can a radon problem be fixed?

Radon problems can be fixed several ways. Active soil depressurization and ventilation are two common ways. A certified radon mitigation professional can help determine the best way to fix your school’s radon problem.

Active soil depressurization (ASD)

ASD is the most common radon reduction method. One or more suction points are drilled through the foundation into the crushed rock or soil below. The number and location of suction points needed depends on how easily air can move below the foundation and on the concentration of radon in the soil. The air is then exhausted away from the building through a 3- or 4-inch PVC pipe. There are different types of ASD systems. Your school’s foundation type will determine which ASD system will work best.

Ventilation

Ventilation can be used as a radon reduction method. Outdoor air can be added to dilute indoor radon levels using a heat recovery ventilator (HRV) or your existing ventilation system. Increased ventilation can improve indoor air quality but be mindful of potential energy costs. Air can also be moved to pressurize a building or room so radon gas cannot enter. Blowing air into the basement or affected room from either another area of the building or outdoors creates pressure and prevents radon from entering.

Your school may already have a ventilation system that can be modified to reduce radon levels. Your certified radon mitigation professional should consult with a qualified ventilation professional when any ventilation system changes are proposed.

Who should fix my school?

Hire a radon mitigation professional certified by the National Radon Proficiency Program or the National Radon Safety Board. If your mitigation professional determines that adjusting HVAC settings can help fix the radon problem, consult with an HVAC engineer before making adjustments.

What should I look for in a certified mitigation professional?

Choose a contractor to fix a radon problem just as you would choose someone to do other building repairs. It is wise to get more than one estimate, to ask for references, and to contact some of those references to ask if they are satisfied with the contractors' work.

When evaluating a contractor for school radon mitigation, ask the following questions: