Advanced Photon Source

An Office of Science National User Facility

Experiment Hazard Class 4.3b – Use of Class 3b Lasers


This hazard classification applies to all experiments involving class 3b lasers. Other hazard classifications and their associated hazard controls may also apply to experiments in this hazard class.

Class 3b lasers are a pulsed or CW, visibule or invisible beam laser that produces sufficient power or energy to cause retinal or other injury to the eye from even momentary exposure to the direct beam or specular reflections.  Class 3 laser output cannot exceed 0.5 watts for periods >0.25 secords or 0.125 joule for periods<0.25 seconds

Experiment Category

Experiments involving previously reviewed hazard controls qualify for medium risk.

Experiments involving new equipment or modified hazard control schemes are categorized as high risk.

Experiment Hazard Control Verification Statements

Before a class 3b laser is first used at the APS, appropriate engineered controls and procedural controls must be developed and implemented. See the summary of laser operation requirements and model SOP.

Engineered Controls – The engineered controls for an existing reviewed and approved laser installation should already be in place and described in necessary detail in the applicable standard operating procedure. Guidance for new installations is available at the link in the paragraph above.

Procedural Controls – All work with class 3b lasers must be performed in accordance with a standard operating procedure (SOP). The procedure must have been reviewed and approved by the APS and the Argonne Laser Safety Officer (LSO). Experimenters can obtain copies of SOPs for existing laser facilities from the appropriate LCA Supervisor. Guidance for new installations and a model SOP are available at the link in this section's introductory paragraph.

Design Reviews and Equipment Inspections – All Class 3b lasers at Argonne must be registered with and reviewed by the Argonne Laser Safety Officer (LSO) and an ANL Laser Operating Permit, ANL-609A must be obtained. Please contact the APS Laser Safety Officer (630-252-6714, to obtain an ANL-609A form. All SOPs must be reviewed and approved by APS management.


  • ESH120, Laser Safety Training
  • Orientation to standard operating procedure for the laser facility
  • Note: If the Argonne LSO approved SOP for the laser system includes a "User Mode" of operation that utilizes engineered controls to reclassify the system as only a class 1 or class 2 equivalent, then the requirement for training and eye exams is waived for "User Mode" only operation. Any other mode of operation of the laser would reinstate the training and eye exam requirements.

Signs and Labeling – Required signs and labeling should already be in place for previously reviewed laser facilities. The requirements specific to an installation should be listed in the associated standard operating procedure. Lasers brought to the APS must have a label that clearly indicates the class of the laser. The Argonne LSO or the APS will provide signs needed for new installations.

Personal Protective Equipment – PPE requirements for laser usage are specified in the associated standard operating procedure

Dosimetry and Monitoring – As of March 1, 2018 Argonne has moved to incorporate the latest laser safety ANSI standard (ANSI Z136.1-2014 Standard for Safe User of Lasers).  Adoption of this standard eliminates the baseline eye and termination examination reuirements for class 3B and 4 laser users, which has been referred to as "Laser Worker Medical Certificaton".  Those workers who have a suspected accidental laser eye or skin exposure should still report this immediately in accordance with LMS PROC-157: Incident Notification.

Experiment Authorization

Unless otherwise noted in the approved experiment safety plan, the PSC Deputy Associate Laboratory Director of Operations delegates the authority to authorize an experiment in this hazard class to the AES ES&H Coordinator or his delegate, a member of the APS Experiment Safety Review Board, and resident beamline personnel appearing in the Director of the AES's list of personnel having the authority to authorize experiments.

Hazard Control Verification

The PSC Deputy Associate Laboratory Director of Operations delegates responsibility for verifying that required controls are in place to the experiment On-site Spokesperson and the local beamline Laser Safety Officer


LMS-PROC-285: Laser Safety 12/18/2013 (Internal link)

Please contact Bruce Glagola or Nena Moonier if you can not access the internal link

Reviewed: March 14, 2017