Ultraviolet Light Safety

St. Lawrence University - Radiation Safety

Return to the Laser Safety Home Page

Guidelines for Ultraviolet Light Emitting Devices:


Ultraviolet (UV) light (180-400 nm) is harmful to cells and tissues. It is unfortunate, but genetic material (DNA and RNA) absorb UV light because of their chemical structure and this absorbed energy causes severe damage. Cells have enzymatic repair systems designed to repair this damage, but not all of it gets repaired correctly. This causes the accumulation of permanent changes in the genetic material, usually referred to as mutations. This is the basis of most biological aging and may also lead to the development of many forms of cancer. Most people are aware of the link between sun UV exposure and skin cancer, for example. It is important to avoid UV exposure when possible.

There are several sources of potentially harmful ultraviolet light exposure on the St. Lawrence campus. These include germicidal lamps in tissue culture facilities, trans-illuminators for viewing electrophoresis gels, fluorescence microscopes, and spectrophotometers in science labs. Welding devices also give off UV light when in use.

Safety Guidelines:

Enclosed UV sources should not be turned on if the enclosure is opened or modified without using proper personal protective equipment.

UV blocking eyewear must be available and used by all persons using and in the proximity of UV emitting devices.

For open sources of UV light, such as tissue culture hoods, full-face shields must be worn when using the germicidal lamps. The culture hoods must not be used while the germicidal lamp is turned on. Appropriate skin coverage should also be considered. Most lab coats afford effective UV blocking ability.

Trans-illuminators that do not have protective shields or shields that are removable must only be used with a full face shield.

Latex (not vinyl) gloves should be worn to protect the hands from UV exposure.

All UV light sources must be prominently marked with appropriate warning signs.

Report all incidents and accidents to your immediate supervisor, department chair or to the RSO as soon as possible.

Return to the Laser Safety Home Page