When CFL lamps were first introduced, there were alarmist claims of radioactivity. Many of the complaints came by way of the manufacturers of incandescent lamps.
Of course, it is true that CFL lamps produce far more UV radiation per watt than incandescent bulbs, but that kind of radiation is not nuclear and causes few problems. As it turns out– at least one manufacturer, and they happen to be the Philips which is the largest maker of CFL lamps in Europe – does intentionally add a small amount of radioactive emitter to the gas in their bulbs to provide quicker startup. Typically Philips uses krypton-85 which is produced as a by-product in fission reactors. Because of consumer complaints, Philips is attempting to eliminate the radioactivity from the consumer market. https://www.wiseinternational.org/nuclear-monitor/329/compact-fluorescent-lamps-radioactive-surprise The Philips CFL bulbs and particularly the older ones sold in Europe will register a signal on a radiation monitor. It is generally a weak signal and does not require that the lamp be turned on. The older the lamp, the more likely it will be “hot” but the level should be nano-Curies - in the range of a banana 😊 The one detail which is not fully understood is that when using some types of radiation detectors, the radiation signal is higher with the bulb turned on than off. This could relate to the UV but in general, the higher the level of radioactivity which is seen, the higher the efficiency of the lamp in lumens per watt. BTW – the fatal dose for radiation poisoning is about 200 bananas in one day. Fortunately, the 40K which is the culprit - is rapidly excreted.
