CFL bulbs contain a lot of mercury. We tested them several months ago with a mercury meter.

We broke an incandescent bulb and got zero mercury vapor readings. We broke a conventional fluorescent bulb and got huge readings. We then broke a CFL and the readings were off the scale.

However, we took readings from all types of bulbs before they were broken and got no mercury from them. We also conducted some tests a few years ago and got the same results from bulbs that were turned on inside boxes for 24 hours.

It's likely that what weety said was true. Fluorescent lights (of which CFL are a type) use high voltages internally and give off electromagnetic pulses (a type of EMF radiation). It's well known that those with metal toxicity react badly to EMF, especially those with mercury toxicity.

We believe that mercury is actually mobilized in the body in the presence of EMF. This is why mercury toxic people don't do well with CRT monitors. Flat screen monitors don't use a CRT. CRT (the big "tube" you actually look at when view this type of monitor) gives off EMF pulses much like fluorescent lights do because of the high voltages of AC (alternating current) they use internally.

There is also another issue that people often miss. Fluorescent bulbs (including CFL) also flash on and off too rapidly to see. Incandescent lights do not do this. This flashing can cause fatigue, especially in the eyes.

Hope this helps.