A few years ago, possible risks associated with blue (and therefore white) LEDs were identified and categorised by greatest concern, both in terms of the severity of the associated hazards and the probability of occurrence in the context of a generalised use of LEDs. The potential risks included cumulative photochemical effects of blue light, glare, and other risks including disruption of circadian rhythms.
Now, an E.U. committee specialising in emerging health risks have found "no evidence of direct adverse health effects" from LEDs in normal everyday use, and determined that studies pointing to health risks have tended to be based on conditions and exposure levels that don't reflect real life. The committee issued their findings in a detailed report on the potential hazards of LED lighting.
Nevertheless, that doesn't mean everything's necessarily fine. There is significant evidence associated with some of the potential risks coming from high-luminance light sources, especially those with an output spectrum rich in blue wavelengths.