CFLs emit ultra violet (UV) light
Manufacturers say there is no health risk for prolonged usage, as eight hours of exposure to CFL UV light is about the same as one minute in full sunlight. For the average person this shouldn’t be a problem, however, people with light sensitive disorders may feel differently. Some international studies revealed even small amounts of CFL UV light can aggravate symptoms in chronic actinic dermatitis (CAD), a state where the skin becomes inflamed after reacting to sun or artificial light, and solar urticaria, a rare condition in which exposure to UV light induces a case of hives on both covered and uncovered areas of the skin. For the general population, in order to evade skin and retinal damage studies in Canada and elsewhere suggest avoiding CFL exposure at distances less than 12 inches which could approach, but not exceed, acceptable limits. There is no cause for concern regarding skin cancer.
Blue Light radiation, Flicker, Hums, Electric Magnetic Fields (EMF)
These issues are associated with older florescent lights and affected people with conditions including epilepsy, lupus, and autism. According to the experts newer CFLs no longer pose a hazard.
For a list of further myths and facts about CFLs see this report by Consumer Reports.