Radon in schools is a real exposure issue, because a school is where most children and staff spend a large part of their day. The U.S. EPA recommends that all schools nationwide test for radon and act to bring levels below 4 pCi/L. The only way to know whether a classroom is affected is to measure it. This guide covers why schools matter, how testing is done, what the numbers mean, and where Ohio stands, with notes for parents, teachers and district facilities staff.
TL;DR
- For most schoolchildren and staff, school is likely the second-largest source of radon exposure after home, according to EPA.
- EPA recommends testing all schools and suggests starting with short-term tests in frequently occupied rooms that touch the ground.
- A short-term result of 4 pCi/L or higher calls for follow-up testing before a mitigation decision. It is not a reason to panic, and it is not one to ignore.
- Ohio does not yet require school testing. A 2026 bill, House Bill 820, would change that, so check its current status.
- Fixes such as sub-slab depressurization and HVAC adjustments work in school buildings, and retesting confirms they are working.
Table of Contents
- Why radon in schools matters
- How Ohio compares
- Is radon testing required in Ohio schools?
- How a school should be tested
- What a result of 4 pCi/L or higher means
- What happens when radon is confirmed
- Our perspective
- What parents, teachers and facilities staff can do
- Getting your building tested or fixed
- FAQ
- Sources
Why radon in schools matters
Radon is a radioactive gas formed by the decay of uranium in soil and rock. It seeps up through foundation cracks and other openings and collects indoors. EPA notes that prolonged exposure to elevated levels increases lung cancer risk, and that the Surgeon General has called it the second-leading cause of lung cancer deaths.
Schools matter for two reasons. First, the hours add up: a student spends roughly 180 days a year in the same building, and a teacher or custodian spends years in it. Second, children are a concern in their own right. Ohio Rep. Kellie Deeter, who sponsored the school testing bill, has said that children's lungs are still developing, that they have a longer lifetime window of exposure, and that exposure can go unnoticed for years.
There are no early warning signs to rely on. Radon cannot be seen or smelled, and lung cancer from it typically takes years to develop. If you want the health timeline in more detail, see our explainer on radon exposure symptoms and how long cancer takes to develop.
Why one school can differ from the next
The Ohio Department of Health (ODH) says nearby schools can show dramatically different radon levels because of local geology, building structure and HVAC systems. Its conclusion is blunt: testing is the only way to know whether rooms in a given school have elevated levels. A newer building is not automatically safe, and an older one is not automatically a problem.
How Ohio compares
Ohio sits in a high-radon part of the country. The 2026 Ohio Radon Report Card from the Indoor Environments Association and AARST shows that 53 of Ohio's 88 counties are EPA Zone 1, the highest-potential category, and that the state's average radon level is 8.9 pCi/L. The same report card counts 2,559 radon-induced lung cancer cases in the state.
Those figures describe the state, not any one classroom. Still, they explain why Ohio districts, and the Greater Cincinnati area in particular, have reason to look. If you want to see how your own area looks, our Ohio radon levels by ZIP code map is a good starting point, and our page on Greater Cincinnati radon testing covers the local picture.
Is radon testing required in Ohio schools?
At the time of writing, testing is recommended in Ohio, not required. The ODH guidance on radon testing in schools makes two points districts should know:
- Anyone offering professional radon testing or advice in Ohio needs a current ODH radon tester or mitigation specialist license.
- School personnel may test buildings their district owns or leases without a license.
So a district can start with its own staff, and many hire a licensed professional for a more defensible, documented result. Both routes are legitimate under the ODH guidance.
House Bill 820
In April 2026, legislators introduced Ohio House Bill 820. According to the Columbus Dispatch, it would mandate radon testing in schools and provide $14 million to help districts with the process. The bill's title also covers home radon tax credits. Bills change as they move, and this one may be amended, passed or stalled by the time you read this, so check the current status and text on the Ohio House page for HB 820.
Even if the bill never passes, the direction is clear. Districts that test now are ahead of any future requirement, and they can answer parents' questions with data.
How a school should be tested
EPA's school guidance lays out a staged approach. Radon testing fits into the same routine walk-throughs many districts already do for indoor air quality, using floor plans to count the rooms and decide how many kits are needed. Here is how that looks in practice.
- Map the building. Get floor plans and mark every frequently occupied room that is in contact with the ground: slab-on-grade classrooms, ground-floor offices, basement rooms in regular use, and rooms over crawl spaces.
- Choose the test type. EPA suggests initial short-term testing in all frequently occupied, ground-contact rooms. Short-term tests give an answer in days, which is useful for screening a whole building.
- Plan the schedule. Testing is usually done with the building closed-building conditions in mind, so the result reflects a normal operating week and not an open-window one. Coordinate with the facilities team so the HVAC runs as it normally does during school hours.
- Place the devices. Use the number of kits the floor plan calls for, keep them away from drafts, exterior walls and vents, and record each location.
- Send for analysis and document. Keep the results by room. A record is what lets a district show parents and boards what it did and when.
- Follow up where needed. Rooms at or above 4 pCi/L go to the next step, covered below.
Upper floors are generally not the priority, since radon enters from the ground. Your state radon program can help with plans and kit types, and in Ohio a licensed tester can do the whole job. Our radon testing service follows the same logic: tailored, site-specific measurement rather than a one-size-fits-all placement.
What a result of 4 pCi/L or higher means
EPA advises schools to take action to bring levels below 4 pCi/L. That number is an action level, not a line between safe and dangerous: there is no known risk-free level of radon, and lower is better.
The handling of results is staged:
| Initial short-term result | What EPA recommends |
|---|---|
| Below 4 pCi/L | No immediate mitigation. Keep records and plan to retest periodically. |
| 4 pCi/L or greater | Follow-up testing before deciding on mitigation. |
| Between 4 and 10 pCi/L | A long-term follow-up measurement, preferably over the school year. |
These steps come from EPA's Radon Measurement in Schools guidance. The reasoning is simple: radon levels swing from day to day and season to season, so one short test can read high or low. A follow-up confirms whether the first reading was typical.
Is a level of 6 high?
A reading of 6 pCi/L is above the 4 pCi/L action level, so yes, it should be followed up. It falls in the 4 to 10 range where EPA points to a long-term follow-up measurement, ideally across the school year, before making a mitigation decision. It is a signal to keep investigating, not an emergency. If a follow-up confirms the number, the district should move toward diagnostics and a fix.
Which month is radon highest?
There is no single month that applies everywhere. Levels change with weather, soil moisture, and how a building is heated and ventilated, and a school's HVAC schedule changes the picture again. This is exactly why a long-term measurement over the school year gives a better average than one short test.
What happens when radon is confirmed
Once elevated levels are confirmed, the next stage is diagnostics: finding out how radon is getting in and how the building's air moves. EPA describes two main strategies that work in schools: active sub-slab depressurization and HVAC pressurization or ventilation. EPA notes that HVAC pressurization and ventilation has been used to bring levels below 4 pCi/L.
Active sub-slab depressurization
This is the workhorse of radon mitigation. Suction points are placed through the slab, and a fan draws radon from beneath the floor and vents it safely outside, before it enters the room. In a school this may mean several suction points and a design shaped by the slab, the footings and any sub-slab ducts. It is the same principle as a home system, just scaled and planned around the building. Our radon mitigation systems are designed on that basis, with the design matched to the foundation type.
HVAC pressurization and ventilation
Sometimes the ventilation system itself is the lever. Adjusting how a building is pressurized, and how much outside air comes in, can keep radon from being drawn indoors. That makes mechanical systems part of the radon conversation, not a separate topic. For a wider view of how air handling shapes occupant exposure, this guide to office air quality and HVAC is worth a read when you are weighing ventilation options in a larger building.
Verifying that it worked
A fix is not finished until it is measured. EPA recommends retesting mitigated systems periodically, and a good project always ends with a post-installation test. After that, a fan is the one moving part, so it pays to watch it. Our guide to radon system maintenance covers what to check and when, and if a system stops performing, these eight checks come first.
Our perspective
We work only on radon, and we see the same pattern at homes, in commercial buildings and in multi-family properties: nobody knows the number until someone measures it, and once it is measured the problem usually turns out to be manageable.
Schools are different from houses in one important way: more people depend on one decision. That is why we think the process matters as much as the result. Test every frequently occupied ground-contact room, keep room-by-room records, confirm any high reading with a follow-up, and never call a fix done until a verification test says so.
We also hold that the design should fit the building. A slab, a basement and a crawl space each call for a different layout, and a commercial building with large mechanical systems calls for a plan made around how the air actually moves. Our work is ANSI/AARST certified for installations, and every mitigation we do includes post-installation verification testing. For larger buildings, see how we approach commercial radon mitigation at 4 pCi/L with less disruption.
Parents and staff can start the conversation without waiting for a mandate. Ask the district whether the building has been tested, when, which rooms were covered and what the results were. A calm, specific question gets a calm, specific answer.
— Yoshua
What parents, teachers and facilities staff can do
- Parents: Ask the school or district for the date and results of its last radon test, and whether ground-contact classrooms were included. Ask what the plan is if a room reads 4 pCi/L or higher.
- Teachers and staff: Raise the question with the principal or facilities manager, and point to EPA's school radon guidance as a practical roadmap.
- Facilities managers: Fold radon testing into existing air quality walk-throughs, keep the floor plans with room-by-room records, and decide in advance who is licensed to test and who will act on results.
- Board members: Budget for testing now. A tested building with records is easier to defend than an untested one, and HB 820 would put money behind it if it passes.
If you also own a home, remember the school is only part of the picture. The same ground that puts radon under a school can put it under your house, and your home is where you spend the most hours.
Getting your building tested or fixed
We test and mitigate in the Greater Cincinnati area, for homes, real estate transactions, new construction rough-ins, and commercial and multi-family properties. Every job starts with site-specific measurement, comes with a fixed written quote, and ends with verification testing. If you manage a building or own a home and want a number, start with our radon testing page, or see everything we do on our services page. If a fan or system is already installed and something seems off, our system repair and fan replacement service is the place to begin.
FAQ
Do schools have to test for radon?
In Ohio, testing is currently recommended, not required. EPA recommends that all schools nationwide test. House Bill 820, introduced in April 2026, would require testing in Ohio schools, so check the bill's current status before relying on either answer.
Who can test a school for radon in Ohio?
Professional testing or advice requires a current ODH radon tester or mitigation specialist license. School personnel may test buildings their district owns or leases without one, according to ODH guidance.
Which classrooms should be tested?
EPA suggests starting with short-term tests in all frequently occupied rooms that are in contact with the ground. That includes slab-on-grade classrooms, ground-floor offices and regularly used basement rooms. Upper-floor rooms are lower priority because radon enters from the soil.
What should a school do with a result above 4 pCi/L?
Follow up before deciding on a fix. EPA recommends a follow-up test after an initial short-term result of 4 pCi/L or greater, and a long-term measurement, preferably over the school year, for initial results between 4 and 10 pCi/L. If the follow-up confirms elevated levels, the school moves to diagnostics and mitigation, then retests to verify.
Can radon in a school be fixed?
Yes. EPA describes active sub-slab depressurization and HVAC pressurization or ventilation as effective strategies in schools. The fix is confirmed by retesting afterward, and periodically thereafter.
Sources
- Radon Measurement in Schools (U.S. EPA)
- Managing Radon in Schools (U.S. EPA)
- Frequently Asked Questions Concerning Radon Testing in Schools (Ohio Department of Health)
- Ohio Radon Report Card (AARST)
- Ohio House bill would require radon testing in schools (Columbus Dispatch)
- House Bill 820, 136th General Assembly (Ohio House)