All of this scare comes from on article written by two dermatologists who claimed that UV lamps were potentially unsafe. Other dermatologists and a celebrity Doctor, then jumped on the bandwagon.
Even if, in the highly unlikely possibility, a client developed a skin cancer on a hand, how could anyone prove that it was a UV lamp, rather than daylight or the flourescent lights in an office that caused this? It is unprovable. This is where the original article falls into the realm of fantasy and should never have been published.
Below is a segment from an interesting article I found that compares nail salon UV lamps with a Narrow Band UV-B skin treatment routinely performed by....DERMATOLOGISTS!
"We elected to compare UV nail lamp irradiance* with exposure of narrowband UVB (NBUVB) used for phototherapy. NBUVB is a commonly used dermatological treatment, viewed as low risk, although not as zero risk.
To achieve the same UV exposure as one course of NBUVB treatments, would need over 250 years of weekly UV nail salon exposure. Our study of three UV nail lamps reveals that such exposure is a tiny fraction of a single NBUVB course, and hence does not produce a clinically significant increased risk of developing skin cancer."
Source: Risk of Skin Cancer Associated with the Use of UV Nail Lamp
Journal of Investigative Dermatology (2013)
*UV irradiance is the amount of UV light energy that falls on a surface of know size. Similar to brightness.