UV radiation is radiation just outside the visible range, or under 400 nanometers (nm). There are three ranges of UV (see table below).
|Region||Also known as||*Range in nm||Hazard Potential||Damage Mechanism (High Exposures)|
|UV-B||mid UV||290-320||mid to high||**skin or eye burns|
|UV-C||far UV||190-290||highest||skin or eye burns|
*Early "black lights" emitted in the range of 360-390 nm.
** Increased risk of some types of skin cancer.
In a University laboratory, one might see UV or ultraviolet lamps used in:
- biological safety cabinets,
- light boxes, and
- cross linkers
When working with UV radiation, one potential hazard is that symptoms of overexposure may not be felt immediately. This means, a person who is over-exposed to UV light may not realize they have been over-exposed until after some damage is already done.
Germicidal lamps emit radiation almost exclusively in the far-UV range of 254 nm. They are commonly used in LaminarAir Flow hoods or biological safety cabinets and should be treated with extreme caution. Never expose yourself to germicidal lamps.
The UV light box is another UV source in use in laboratories. This instrument is a box with a glass top and a UV lamp inside. Some units have multiple lamps that allow a choice of wavelength.
Most of these instruments are stationary, but a few are hand-held types that carry the same hazards as the stationary models. Nucleic acid (DNA or RNA) which has been stained with the chemical Ethidium Bromide, lights up when exposed to UV light.
A UV-Crosslinker is used to "cross-link" or covalently attach nucleic acid to a surface or membrane following Southern blotting, Northern blotting, dot blotting, and Colony/Plaque lifts. Since the DNA will be used in place, a 254 nm wavelength is used to maximize adherence.
Look for a symbol indicating the UV protection rating or check with the manufacturer. If no information is available, contact the UVM Radiation Safety Office.
The health effects of exposure to UV light are familiar to anyone who has had a sunburn. However, the UV light levels around certain UV equipment greatly exceeds the levels found in nature.
Acute (short-term) effects include redness or ulceration of the skin. At high levels of exposure, these burns can be serious. For chronic (long-term) exposures, there is also a cumulative risk of harm. This risk depends upon the amount of exposure during your lifetime. The long-term risk for large cumulative exposure includes premature aging of the skin and even skin cancer.
Do not forget to protect the rest of your face, too. Severe skin burns can happen in a very short time, especially under your chin (where most people forget to cover). Full-face shields are really the only appropriate protection when working with UV light boxes for more than a few seconds.
Be sure to protect your arms and hands by wearing a long-sleeve lab coat and gloves.
The eyes are also susceptible to UV damage. Like the skin, the covering of the eye or the cornea, is epithelial tissue, too.The danger to the eye is enhanced by the fact that light can enter from all angles around the eye and not only in the direction you are looking. The lens can also be damaged, but since the cornea acts as a filter, the chances are reduced. This should not lessen the concern over lens damage however, because cataracts are the direct result of lens damage.
Burns to the eyes are usually more painful and serious than a burn to the skin. Make sure your eye protection is appropriate for this work. There are specially-made safety glasses for the different UV ranges. REGULAR EYEGLASSES CONTACT LENSES OR TYPICAL SAFETY GLASSES DO NOT OFFER APPROPRIATE PROTECTION.
Safety staff can pick up burned out UVM lamps. They are disposed of like all other fluorescent lightbulbs at UVM. Please call 656-5408 for pickups. No need to fill out a lab waste tag for UV bulbs.