Radon license lookup · IL, PA, CO
Check a radon tester's or mitigator's license
Each of the three states keeps a public list. Here is where it is, what it shows, and when we last read it, with the rules for checking a license on the job.
The three state lists
| State | Official list | What it shows | Size | We read it |
|---|---|---|---|---|
| Illinois | IEMA-OHS Radon Active Licensee Listing | License number, license type, name, employer, employer address and phone, commercial building flag, supervising professional. No expiry date. | 622 active licensees | October 15, 2026 |
| Pennsylvania | DEP Radon Services Directory | DEP ID, firm or person, address, county, phone, email, test device codes. Updated monthly; no expiry date. | 137 mitigation and 659 testing rows | October 1, 2026 |
| Colorado | Professional and Occupational Licenses in Colorado (DORA, open data) | Name, town, license number, type (mitigation or measurement), first issue, last renewal, expiry, status, a link to the DORA record. No company or phone. | 233 mitigation and 548 measurement licenses | October 15, 2026 |
Checking a license
- IEMA active licensee lookup
- IEMA-OHS publishes a searchable list of active radon licensees that can be filtered by employer, license type, service county or city.Illinois Emergency Management Agency and Office of Homeland Security (IEMA-OHS), read October 15, 2026
- How to verify
- DEP tells the public to check for a current DEP ID card or certificate, because certification status can change between monthly lists.Pennsylvania Department of Environmental Protection, read October 15, 2026
- ID card on the job
- Certified testers, mitigators and listed firm employees must wear their DEP photo ID card while working and show it to a client on request.PA Environmental Quality Board, 2018 final rule text (posted by DEP), read October 15, 2026
- Accepted certifying bodies
- Certification through the National Radon Proficiency Program or the National Radon Safety Board meets the state's proficiency requirement for either license.Colorado Department of Regulatory Agencies, Office of Radon Professionals (4 CCR 754-1, Code of Colorado Regulations, Secretary of State), read October 15, 2026
- Working without a license
- Doing radon measurement or mitigation, or using a radon professional title, without an active license is a class 2 misdemeanor for a first offense and a class 1 misdemeanor after that.Colorado General Assembly (Session Laws 2021, ch. 398, HB21-1195), read October 15, 2026
- Renewal grace period
- A licensee has 60 days after the license expires to renew without a reinstatement application, but a delinquency fee is charged.Colorado Department of Regulatory Agencies, Office of Radon Professionals (4 CCR 754-1, Code of Colorado Regulations, Secretary of State), read October 15, 2026
National certification: NRPP and NRSB
- State license or national list
- States that receive EPA radon grants must list only providers credentialed by a state process (such as a license) or a recognized national program.U.S. Environmental Protection Agency, read October 15, 2026
- NRPP and NRSB recognized
- EPA recognizes two national certification bodies, the National Radon Proficiency Program (NRPP) and the National Radon Safety Board (NRSB).U.S. Environmental Protection Agency, read October 15, 2026
- Unregulated states: ask
- Where a state does not regulate radon work, EPA says to ask whether the contractor holds a proficiency or certification credential.U.S. Environmental Protection Agency, read October 15, 2026
- Testers are often inspectors
- EPA notes that the qualified radon tester a buyer hires is very often a home inspector.U.S. Environmental Protection Agency, read October 15, 2026
- Credential criteria pending
- EPA proposed new radon credentialing criteria in 2023; the comment period closed and the criteria are not final.U.S. Environmental Protection Agency, read October 15, 2026
Two more states for comparison
- DPH keeps a radon list
- The Department of Public Health keeps a list of radon companies and individuals who appear on approved national proficiency program lists.Connecticut General Assembly, read October 15, 2026
- Mitigators must be certified
- A contractor that does radon mitigation can only register with DCP if certified as a radon mitigator by the National Radon Safety Board or the National Environmental Health Association.Connecticut General Assembly, read October 15, 2026
- No state radon certification
- Delaware does not certify radon testers or mitigators; its Division of Public Health keeps only a voluntary company list.Delaware Division of Public Health, read October 15, 2026
Sources
- Illinois Emergency Management Agency and Office of Homeland Security (IEMA-OHS), read October 15, 2026.
- Pennsylvania Department of Environmental Protection, read October 15, 2026.
- PA Environmental Quality Board, 2018 final rule text (posted by DEP), read October 15, 2026.
- Colorado Department of Regulatory Agencies, Office of Radon Professionals (4 CCR 754-1, Code of Colorado Regulations, Secretary of State), read October 15, 2026.
- Colorado General Assembly (Session Laws 2021, ch. 398, HB21-1195), read October 15, 2026.
- U.S. Environmental Protection Agency, read October 15, 2026.
- U.S. Environmental Protection Agency, read October 15, 2026.
- U.S. Environmental Protection Agency, read October 15, 2026.
- Connecticut General Assembly, read October 15, 2026.
- Connecticut General Assembly, read October 15, 2026.
- Delaware Division of Public Health, read October 15, 2026.