Even though R-22 is considered non-toxic, it _______.

Even though R-22 is considered non-toxic, it can cause asphyxia.
Asphyxiation, which is suffocation resulting from a lack of oxygen, can occur when refrigerants are released and present in mechanical rooms, confined spaces, etc.
Because the refrigerant is heavier than the oxygen you breathe, it actually displaces oxygen from the floor up and deprives you. This is why refrigerant sensors that actuate alarms and ventilation equipment are mandated for mechanical equipment rooms.