Answer to Question #11826 Submitted to "Ask the Experts"

I was working in my biosafety cabinet fume hood and accidently left the ultraviolet-C (UV-C) germicidal lamp on for around 15 minutes. There was a fume hood sash between the lamp and me, and I was wearing the appropriate personal protective equipment (i.e., lab coat and latex gloves); however, there was an uncovered part of skin between my gloves and lab coat which came into direct contact with the UV-C light during that time. After a few hours, I observed skin flaking off from the exposed areas as well as it being slightly painful to touch. I am concerned with the long-term effects of this acute exposure and my chances of getting skin cancer. Additionally, I understand that there are different claims about the health effects of UV-C light on humans, and I was wondering about the reason for these multiple different claims.

The small portion of your skin between your gloves and the lab coat that was exposed to the UV-C essentially received a small sunburn, as one might receive from being in the sun for an extended period of time without sun protection. Although long-term exposure to ultraviolet light and extensive periods of time in the sun are associated with skin cancer, the increased risk is proportional to the amount of time you were exposed. The short period of time you were exposed is not expected to result in an observable increase in the risk of skin cancer. In the future, you might consider applying a sun protective cream or ointment (with sun protection factor [SPF] 50 or greater) to your wrist areas or where your skin might be exposed to the UV-C light.

In response to your question regarding the different claims about exposure to UV-C to humans and skin cancer, the science behind the association of skin cancer and UV-C exposure is strong. Many scientific studies have shown a direct relationship between exposure and cancer or exposure and cellular damage. These studies have included both animal and human cells. Studies have also shown that long-term exposure to UV tanning beds is associated with skin cancer. The website of the Skin Cancer Foundation has excellent discussions of the health effects of and treatments for overexposure to UV light.

To summarize our answer to your question regarding your exposure to a UV-C light source, you received a sunburn to your skin. The risk of developing skin cancer in this area is minimal unless you continue to receive multiple exposures in this area of your body. To reduce the chance of cancer, we recommend that you apply sunscreen with a protective factor of at least SPF 50 to protect the exposed areas.

Paul Charp, PhD