Ultraviolet radiation (UV) is a form of non-ionizing radiation emitted from natural and artificial sources. The UV spectrum ranges from 100-400 nanometers and is located between visible light and X-ray on the electromagnetic spectrum. The ranges of non-ionizing UV can be charted into three regions:
Most natural UV from sunlight should be avoided by use of personal protection such as a hat, sunblock, and sunglasses. However, UV radiation from laboratory equipment is in a more concentrated form which poses a greater threat to personnel. If no personal protection equipment is used, tissue damage may occur in only a few seconds.
Typical laboratory equipment with the capacity to emit non-ionizing UV wavelengths includes:
· Biological safety cabinets (BSCs)
· Transilluminator boxes
· UV crosslinkers
· Photoreactors
· Handheld or stationary UV curing lamps
· LED lights in the 245- 808 nm range
Exposure to UV light poses a serious threat to both the eye and skin. Corneal and skin burns are the most common injuries from unprotected use of UV emitting devices.
Eye injury can occur due to very brief exposure or with just a flash of intense UV. Being at the cutaneous level, the cornea of the eye is also very susceptible to UV radiation and is extremely vulnerable because of its lack of thickness. UV exposure can cause lesions of the cornea and ultimately cause photokeratitis (inflammation). Symptoms are described as a sensation of sand in the eye that may last for several days. Other symptoms of an overexposed eye may occur within a few hours and include sensitivity to light, unexplained tearing, and a burning or painful sensation in the eye.
Erythema, or sunburn of the skin, usually proceeds via photochemical and thermal reactions into the dermal skin layers and can occur within a few seconds of exposure to concentrated UV. Prolonged and repeated exposure to ultraviolet light also causes premature dermal aging and cancer of the skin.
Exposure can result in symptoms comparable to normal sunburn and include redness, swelling, pain, blisters and peeling on the burned area. Severe sunburn can lead to headache and nausea like conditions. Variables for this intensity are mostly genetic factors but can be exaggerated by photosensitization from certain foods or drugs.
Personal Protective Equipment (PPE): Always wear PPE such as safety glasses/face shields, and lab coats (long sleeves) and gloves when using UV light. Clear polycarbonate safety glasses are a great choice for eye protection. Polycarbonate lenses are highly impact resistant and provide built-in UV protection, which means they block harmful ultraviolet rays without needing any additonal coatings.
Label Equipment Properly: Overexposure of UV radiation almost always occurs because of inadequate education with regard to hazards when using UV emitting equipment. All equipment should be obviously and specifically labeled pertaining to UV emission. Properly labeled equipment decreases the likelihood of an accident involving exposure to the eyes and/or skin. To obtain UV Hazard labels, contact the UK Department of Research Safety at labsafety@uky.edu or (859) 323-6777.
Do Not Use UV as the primary means of decontamination (i.e., biological safety cabinets): “The NIH does not recommend or support the use of ultraviolet (UV) radiation in laboratories. Although UV is effective against most microbes, it requires an understanding of its abilities and limitations. The 253.7-nm wavelength emitted by the germicidal lamp has limited penetrating power and is primarily effective against unprotected microbes on exposed surfaces or in the air. It does not penetrate soil or dust. The intensity or destructive power decreases by the square of the distance from the lamp. Thus, exposure time is always related to the distance. The intensity of the lamp diminishes over time. This requires periodic monitoring with a UV meter. The intensity of the lamp is drastically affected by the accumulation of dust and dirt on it. The bulbs require frequent maintenance. In addition, there are safety hazards associated with the use of UV that require personal protective equipment or other safety devices to protect users. UV lights in biosafety cabinets require the cabinet be decontaminated prior to performing maintenance on the system. Past experience has proven that good techniques in conducting experiments are highly effective in preventing contamination. The use of UV radiation does not eliminate the necessity for using good practices and procedures." *
If installed, UV lamps should be cleaned regularly to remove any film that may block the output of the lamp. The lamps should be evaluated regularly and checked with a UV meter to ensure that the appropriate intensity of UV light is being emitted. Replace the bulb when the fluence rate is below 40 uW/cm2. Unshielded UV lamps must be turned off when the room is occupied to protect eyes and skin from UV exposure. If the cabinet has a sliding sash, close the sash when operating the UV lamp. Most new BSCs use sliding sashes that are interlocked when operating the UV lamp to prevent exposure.
*https://www.ors.od.nih.gov/sr/dohs/safety/laboratory/BioSafety/Pages/decontamination.aspx