Commercial testing and mitigation are just starting to be addressed. The EPA issued testing and mitigation requirements based on their studies. They are involved in radon regulation for commercial properties because of the amount of time people are exposed at work - at least 8 hours a day 5 (or more) days a week.
Being exposed to radon for that amount of time will almost certainly mean that regulations will be put in place. After all, if homeowners will be required to take proper precautions to remove radon in the home, the danger in workplace is enough that the same rules for home safety should apply to a workplace.
The EPA will act because of the precedents set about unsafe working conditions in “sick buildings” caused by mold, chemical residues and embedded bacteria. Some legal actions will certainly occur and the safe level will be established, requiring commercial property owners to take action.
HUD already has rules that require that at least 25% of randomly selected ground level units in existing properties be tested for radon, with mitigation required based on high levels. HUD's policy is based on mitigation done on a per-building basis, not on a per-unit basis.
HUD rules may change because AARST-ANSI standards protocol requires that 100% of units be tested. Enforcement of testing is on the same level as testing for mold.
Commercial and residential radon mitigation systems are similar – they both use a slab (or sump pump) as the entry point for piping to channel radon gas from the soil below the building and suffuse/ diffuse the gas and air mixture into the atmosphere.
However, commercial properties – including offices/apartments/retail stores/condos tend to have higher indoor air flow which increases the “stack effect,” which makes passive mitigation problematical. Engineering active systems for these locations can be amazingly difficult.
Commercial buildings also have multiple structural types which means that there can be multiple radon entry points. Radon mitigation designs are largely “one off’s” because there are so many different variables and issues to consider. This is also true of schools,
Commercial mitigation installations may also have to work around daily operations – owners of retail, apartment, and office properties are not keen on having their tenants’ schedules disrupted during normal hours, while school, retail and condo properties have their own set of issues.
Unlike residential active mitigation, which involves fans, commercial properties have tended to use Active Soil Depressurization (ASD.) ASD works by stabilizing and equalizing the pressure between the soil outside the building and the air inside.
Without ASD, pressure is higher in the surrounding soil than it is inside the building, so radon is then drawn into the building through tiny cracks and holes, causing contamination. WITH ASD, soil depressurization causes the pressure inside and out to be equalized and this draws out radon from underneath the building, lowering or eliminating the amount of radon INSIDE the building.