I just got a crank email from one of my former neighbors, bitching about the mosque up the road from my old house. Among the complaints about parking, un-permitted construction, and the like, is this gem:
Huh? “Blue/white spectrum” lights cause cancer? Whats the straight dope on this?
The mercury vapor lamps can emit dangerous amounts of UV when the bulb is damaged and still operates in the fixture. Warnings on that have been out for decades, so I’ll guess the person writing this crap, just twisted the information a bit much.
Er, not to provide information in support of a nutjob/hater; but since you asked, there is also the remotely possibly related fact that one’s pineal gland produces melatonin only during REM sleep (I think) and only in darkness (I know). Melatonin is thought to help protect against some forms of cancer.
However, AFAIK there is no distinction between the red and blue ends of the visible-light spectrum — all light inhibits production.