Certified radon testers & mitigatorsRhode Island — testing — verified 29 Aug 2026

§ 4.1 — Johnston, RI

Certified radon testing in Johnston, RI

1 current listing from the official file. Verify the credential number before you hire.

Last verified August 29, 2026. Methodology RI RIDOH.

Certified radon testingCertified radon mitigation

  1. Mario Fonseca Environmental Inspections

    Mario Fonseca Environmental Inspections

    current RI RIDOH № RTB00136

    testing

    (401) 529-0928August 29, 2026cite ↗
Fig. 4 — Johnston, RI, approximate. Pin is the city on the official file, not a street address.

Appendix A — Before you hire

  1. Who holds the credential, and can they show the same number that appears on this page?
  2. What test method or mitigation system will they use for this building?
  3. How will they document results or the finished system?

§ 4.3

Nearby places in Rhode Island

Rhode Island Department of Health licenses radon testing businesses and mitigation contractors. The firms below appear on the official RIDOH Find Radon Licensees listing we imported. Laboratories are not listed here. Read the methodology. Credential status can change.