The bill amends Chapter 5-20.8 of the General Laws by introducing a new section that mandates radon inspection and mitigation for residential real estate transactions. It defines key terms such as "radon," "radon test," and "residential real estate transaction." A radon test must be performed no earlier than one year prior to the closing date for transactions not exempted under specific conditions. Exemptions include transactions involving foreclosures, certain sales by court-appointed trustees, and properties with existing radon mitigation systems that have been tested within the last three years.

The bill requires that if a radon test reveals unsafe levels of radon, a mitigation system must be installed by a certified or licensed individual before closing, or the estimated cost of the mitigation must be held in escrow until the work is completed. The buyer is generally responsible for the cost of the radon test unless the seller provides a certified test indicating safe levels within one year prior to the execution of the purchase and sale agreement. This act is set to take effect on June 1, 2027.