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Laser Safety Guide




Introduction (top)

Most lasers used at Princeton University are capable of causing eye injury to anyone who looks directly into the beam or its reflections from a specular (mirror-like) surface. In addition, diffuse reflections of a high-power laser beam can produce permanent eye damage. High-power laser beams can burn exposed skin, ignite flammable materials, and heat materials that release hazardous fumes, gases, debris, or radiation. Equipment and optical apparatus required to produce and control laser energy may also introduce additional hazards associated with high voltage, high pressure, cryogenics, noise, other forms of radiation, flammable materials, and toxic fluids. Thus, each proposed experiment or operation involving a laser must be evaluated to determine the hazards involved and the appropriate safety measures and controls required.

Laser Safety at Princeton University (top)

The Laser Safety Program is administered by EHS, with the assistance of the Laser Safety Advisory Group. The Laser Advisory Group consists of faculty, staff and graduate students representing the major laser using departments on campus. The Laser Safety Officer for Princeton University leads the Laser Advisory Group. EHS and the Laser Advisory Group recommend that individuals using lasers set up and operate laser facilities to meet the laser safety guidelines established by the American National Standards Institute (ANSI) standard ANSI Z136.1-2007, American National Standard for the Safe Use of Lasers.

The Laser Safety Program applies to individuals who operate or work in proximity to Class 2, Class 3 or Class 4 lasers.

Hazard Classification (top)

Commercial lasers are classified and certified by the manufacturer. When a commercial laser is modified or when a new laser is constructed in the laboratory, it is the responsibility of the principal investigator to classify and label the laser per the ANSI Standard. EHS can assist in determining the appropriate classification. See Table A for a summary of typical laser classifications.

Medical Surveillance (top)

Some individuals who operate or work in close proximity to particular Class 3B or Class 4 lasers or laser systems may receive a pre-assignment and a post-assignment eye examination performed by a consulting ophthalmologist. Results of the examinations are maintained by the Employee Health in University Health Services at McCosh. Contact the Laser Safety Officer for more information.

Training (top)

Individuals who work with or in close proximity to Class 2, Class 3, or Class 4 lasers must attend laser safety training provided by EHS. This training includes:

  • fundamentals of laser operation
  • biological effects of laser radiation on the eye and skin
  • non-radiation hazards (e.g., fire hazards, chemical exposure)
  • classification of lasers and laser systems
  • control measures and personal protective equipment

Individuals who work with or in close proximity to Class 3B or Class 4 lasers receive additional training from EHS, including:

  • relations of specular and diffuse reflections
  • radiometric units and measurement devices
  • maximum personal exposure levels or eye and skin under all conditions
  • laser hazard evaluations and range equations

Roles and Responsibilities (top)


  • Identify laser products that are covered by the ANSI Standard and establish procedures to ensure that the recommendations of the Standard are followed.
  • Ensure individual who work with or around lasers have received the proper laser safety training.
  • Establish a safety review procedure to determine that adequate hazard analyses and corrective actions have been completed for all applicable laser systems


  • Be knowledgeable of the education and training requirements for laser safety, the potential laser hazards and associated control measures for all lasers under their control.
  • Report known or suspected accidents to EHS.
  • Ensure that lasers under their control are not operated or modified without approval of the supervisor or principal investigator.
  • Ensure that all administrative and engineering controls are followed.
  • Maintain inventory control and a permanent record of the status of all Class 3B, and Class 4 lasers
  • Ensure that individuals working with lasers have attended the general laser safety training and provide laser operators with training in the administrative, alignment and standard operating procedures.
  • Classify and label any unclassified lasers
  • Attend University's laser safety training programs.
  • Ensure that laser workers are registered for the medical surveillance program.
  • Notify EHS immediately in the event of an exposure to a Class 3 or Class 4 laser.
  • Provide standard operating procedures (SOP), in accordance with ANSI Z136.1-2007 and any established University policy, for all laser operations involving Class 3 and Class 4 lasers detailing alignment, operation and maintenance procedures.

Puchasing Office

  • Notify EHS when orders for Class 3 and Class 4 lasers are placed


  • Review and approve the purchase of Class 3 and Class 4 lasers
  • Provide assistance in evaluating and controlling hazards.
  • Maintain records of lasers and laser operators.
  • Conduct laser safety training.
  • Participate in accident investigations involving lasers.
  • Periodically audit the departmental Laser Safety Program.


  • Attend laser safety training
  • Be familiar with specific safety hazards of lasers which is being operated or working near.
  • Follow standard operating procedures and comply with requirements established by the Laser Safety Committee, Laser Safety Officer and the supervisor.
  • Use Class 3B or Class 4 lasers only if specifically authorized by the laser supervisor.
  • Report known or suspected accidents to the supervisor and EHS.
  • Inform spectators about and protect spectators from all potential laser hazards
  • Register for the medical surveillance program.

References (top)

Contact the Laser Safety Officer at 258-6271 for more information.

The following resources and training aids are available through EHS:

  • ANSI Standard Z136.1-2007, American National Standard for the Safe Use of Lasers, 2007
  • CFR Chapter I, Subpart J, Part 1040 - Performance Standard for Light Emitting Products (the Food and Drug Administration requirement document for light emitting products.
  • Videocassette: High Powered Lasers in the Lab, Interactive Media Communications, 1994
  • Goldman, Leon, Application of the Laser, CRC Press, 1977
  • Pressley, Robert J., Ph.D., editor, CRC Handbook of Lasers, CRC Press, 1971
  • Seigman, Anthony E., Lasers, University Science Books, 1986
  • Mallow, Alex and Leon Chabot, Laser Safety Handbook, Van Nostrand Reinhold, 1978

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