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Environmental Health and Safety

Laser Safety

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Laser is an acronym for Light Amplified by Stimulated Emission of Radiation.  It is a device that creates and amplifies a narrow, intense beam of coherent light.  First built in 1960, lasers now range in size from semiconductor lasers to solid-state and gas lasers and as large as a storage building.  Lasers are employed over a huge range of applications such as basic scientific research, surgical and diagnostic techniques, telecommunications, entertainment, industrial cutting and measurements, and military and law enforcement.

CLASSES OF LASERS

The American National Standards Institute (ANSI) has established a laser hazard classification system in publication ANSI Z136.1-2000, Safe Use of Lasers.  Certified laser manufactures are required to label their products as to the Class type as of September 19, 1985 (21 CFR Part 1040).  Information regarding appropriate eyewear for a specific laser may be obtained from the manufacturer at time of purchase.  The following table summarizes this laser classification scheme and the hazard capabilities associated with each class of laser.

Class of LaserHazards
1Eye safe lasers; may not produce hazardous radiation
2Continuous intrabeam viewing can cause eye damage; momentary intrabeam exposure (< 0.25 sec) is not damaging to the eye; visible radiation only
2aContinuous intrabeam viewing can cause eye damage; the accessible radiation shall not exceed Class 1 accessible emission limit (AEL) for an exposure duration of 1000 seconds
3aInvisible lasers having an output power < 5x the Class 1 AEL or visible laser having an output power < 5 mW; capable of causing damage through intrabeam viewing, with optical instruments or through viewing a specular reflection for < 0.25 sec
3bInvisible lasers having output power <500 mW; as with 3a lasers, 3b lasers can cause injury through intrabeam viewing, viewing with optical instruments, or through viewing a specular reflection
4Beam power > 500 mW; intrabeam exposure, exposure to specular- and diffuse reflections capable of causing eye- and skin damage; fire hazard due to their power density

LASER HAZARDS AND PRECAUTIONS

Laser use can create intense concentrations of heat, ultraviolet, infrared, and reflected light radiation. Unprotected laser exposure may result in eye injuries including retinal burns, cataracts, and permanent blindness. An appropriate eye protection must be used at all times when working with lasers. The selection of laser protection should depend upon the lasers in use and the operating conditions.

Beam Hazards

Always protect the eyes from exposure to laser beams.  Choose laser goggles with wavelength-specific lenses and opaque non-lens components.  Eye exposure is most likely to occur during beam alignment.  NEVER UNDER ANY CIRCUMSTANCES LOOK DIRECTLY INTO THE LASER BEAM.

Non-Beam Hazards:

Electrical Hazards
Learn rescue procedures for helping victims of apparent electric shock: kill the circuit; have someone call for emergency aid; remove the victim with a non-conductor if s/he is still in contact with the energized circuit; initiate artificial respiration immediately and continue until emergency medical personnel arrive.

Precautions to take:

  1. Install Ground Fault Interrupters (GFI) in laboratories in which lasers are used.
  2. Provide enclosures to prevent accidental contact with terminals, cables, and exposed electrical contacts. Provide a grounded metal enclosure that is locked/interlocked.
  3. Remove nearby flammable/combustible materials to limit fuel in the event of fire.
  4. Never handle electrical equipment when hands, feet, or body are wet or perspiring or when standing on a wet floor.
  5. With high voltages, regard all floors as conductive and grounded unless covered with a well maintained, dry rubber matting of a type suitable for electrical work.
  6. When possible, use only one hand when working on a circuit or control device.
  7. Avoid wearing rings, metallic watchbands, and other metallic objects.

Other Hazards:

Always consider other hazards such as compressed gases, explosion, fire, x-ray radiation, laser dyes and solvents and mechanical hazards.  Pay special consideration to ergonomic issues to avoid injury.

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