In addition to sunlight, UV light sources are found in the lab and shop. Sources include some biosafety cabinets, certain types of hand-held light sources, transilluminators, crosslinkers, and some laboratory instruments such as spectrophotometers.

UV germicidal lamps, such as in biosafety cabinets, are designed to emit UV-C radiation because of its ability to kill bacteria. In humans, UV-C is typically absorbed in the outer dead layers of the skin. Overexposure to UV-C can cause corneal burns, commonly termed welders’ flash. UV burns to the eye are often described as a “sand in the eye” feeling and are often reported to be very painful. No one should ever work in the biosafety cabinet (BSC) with the UV lamps on, and in reality, the UV lamps should not be on when the room is occupied.

Transilluminators or UV Light Boxes are used for visualization of DNA on gels. They typically look like flat boxes with a glass tops and UV lamps inside. The glass top allows the light to shine on the gel causing the DNA to “glow” but this also potentially exposes the user. To reduce risk of injury, most models today come equipped with a shield to block the UV light. For older models, there are various types of after-market shields that can be attached that may also provide good protection. We have heard of accidents where lab workers have used inappropriate shielding thinking it was rated for UV when, in fact, it was not. The UV shields/cover should be checked regularly for cracks or other damage.

Access to rooms with open source transilluminators should be controlled and posted with a warning sign indicating face and other skin protection is needed to enter when a transilluminator is in use. The protection required is standard laboratory apparel including a fully buttoned lab coat, gloves, long pants, and closed toe shoes. While working with UV radiation sources, lab workers must be careful to prevent gaps in clothing that will expose the skin such as around the neck and wrists. In addition to the standard lab, attire a polycarbonate face shield labeled for UV protection (as opposed to just glasses/goggles) should be worn to protect the eyes and face. It is not uncommon for lab workers to receive facial burns in the areas not covered by the goggles or glasses.

From: Don't Get Burned: UV Exposure in the Workplace by The Safety Guys