Radiation Safety

A laser is a device that emits an intense, pencil-thin light beam.

Laser beams may be different colors and some are invisible. The term laser is an acronym for Light Amplification by Stimulated Emission of Radiation. Lasers present no hazard when turned off.

Lasers are classified according to their capability of injuring personnel. There are five classifications:

Class 1 No hazard. Laser printers are an example.

Class 2 Minimal risk. Visible light only. Natural blink reflex provides protection.

Class 3a Slight risk. Laser pointers are an example. Could be visible or invisible light. Natural blink reflex provides protection.

Class 3b Moderate risk. Capable of injuring the eyes from direct beam or mirror-like reflections.

Class 4 High risk. Capable of injuring the eyes and skin from direct beam, mirror-like reflections, or diffuse reflections.

For high-powered (Class 3b or 4) lasers, injuries may occur from the primary beam or reflected beams. Labs containing these lasers have signs identifying the type and power of laser light, as shown above.

Some labs use a warning light to indicate that the laser is in operation, but this is not a requirement. Areas around high-powered lasers may be controlled using barriers such as curtains; otherwise the entire lab is a laser hazard zone.

If you must enter a laser lab, ask the operator about safety precautions. If no one is present and a high-powered laser is operating, do not enter the hazard zone inside any curtains.

Never stare directly into any laser beam.

Additional information about laser safety and radiation safety can be found on the Division of Research Safety website at: www.drs.illinois.edu/rss/lasers.