The main topic of the article is that scientists in the University of San Diego exposed living cells to UV exposure using a 54W MelodySusie UV nail salon lamp containing six 9W UV bulbs. The cells were exposed to UV light one, two or three times for up to 20 minutes. After 48 hours, the cells were inspected for health and DNA changes.

Although the study used a UV lamp with 9W bulbs, LED lamps also produce UV light so the discussion applies to both types.

Based on their experiments, the scientists state: 

“our experimental results and the prior evidence strongly suggest that radiation emitted by UV-nail polish dryers may cause cancers of the hand and that UV-nail polish dryers, similar to tanning beds, may increase the risk of early-onset skin cancer”

But, in addition:

“While this report demonstrates that radiation from UV-nail polish dryers is cytotoxic, genotoxic, and mutagenic, it does not provide direct evidence for an increased cancer risk in human beings.”

“future large-scale epidemiological studies are warranted to accurately quantify the risk for skin cancer of the hand in people regularly using UV nail polish dryers. It is likely that such studies will take at least a decade to complete and to subsequently inform the general public.”

While the scientists show that it may be possible to damage the DNA of living cells in a petri dish using a high-powered UV lamp, they accept that this experiment does not prove damage to humans and that a 10 year controlled study is required for their theory to be proved conclusive.

As the articles mention, every day more than 3 Million nail services using UV lamps are performed in USA nail salons. On this basis we can estimate that there are perhaps 10 Million nail salon services every day Worldwide, which is approximately 3.6 Billion services per year. UV lamps have been used in nail salons for at least 30 years, so the total number of UV cured nail services is likely to run into Trillions. Despite this enormous number of nail services, until now scientists have failed to prove conclusively or repeatedly, that UV lamps do cause skin melanoma. 

Previous studies have shown that there is little to no carcinogenic risk inherent with UV gel manicures (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7492020/) and that using a UV lamp every day for 25 minutes is within safe limits (https://pubmed.ncbi.nlm.nih.gov/23550905/)

Summary

The article fails to prove that using a UV nail lamp is a health risk. Obtaining that proof through a 10 year study, is likely to be extremely difficult as it would need a large number of nail salon clients, whose lifestyle means that they are not highly exposed to UV light from other sources (bright sunlight, sun beds). 

If there was a conclusive health risk, we could assume that after more than a Trillion UV-cure nail services, the risk to health would already be known. 

Daily Mail article:

https://www.dailymail.co.uk/sciencetech/article-11653629/UV-nail-polish-drying-devices-cause-cancer-causing-mutations-study-warns.html