What does an ionization alarm label indicate about its contents?

An ionization alarm label indicates that the device contains a radioactive material. This is because ionization smoke alarms utilize a small amount of radioactive isotope, typically americium-241, to detect smoke particles. When smoke enters the ionization chamber, it disrupts the flow of ions created by the radioactive material, triggering the alarm. This specific type of technology is sensitive to fast-burning fires but less effective for smoldering fires. Understanding this aspect helps firefighters know what kind of technology they are dealing with when responding to incidents involving smoke alarms.