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


This hazard classification applies to all experiments involving class 3a lasers. Other hazard classifications and their associated hazard controls may also apply to experiments in this hazard class. See the summary of laser operation requirements.

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

Engineered Controls – The laser installation must be posted and include a visible laser "ON" indicator. It is recommended that a Laser Control Area (LCA) be established. There shall be no unshielded eye level or non horizontal beams.  

Procedural Controls – No intentional staring into beam or specular reflections. Avoid shining light toward people. Careful control of spectators and work area shall be maintained by the LCA Supervisor and local beamline management.

Design Reviews and Equipment Inspections – All Class 3a 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 (2-6714, chang@aps.anl.gov) if you can not access the above form. The installation will be approved by the Argonne LSO and APS management.

Training –

  • ESH121, Low Power Laser Safety Training or ESH120, Laser Safety Training (determined by Argonne Laser Safety Officer (LSO)).
  • Orientation to standard operating procedure for the laser facility

Signs and Labeling – The area where the laser is used (e.g. experiment station) shall be posted. Lasers brought to the APS must have a label that clearly indicates the class of the laser. The Argonne LSO or the APS LSO will provide signs needed for new installations.

Personal Protective Equipment –Laser protective eyewear may be required and is determined by the Argonne LSO.

Experiment Authorization

Unless otherwise noted in the approved experiment safety plan, the Director of the APS Engineering Support Division 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 Director of the APS Engineering Support Division delegates responsibility for verifying that required controls are in place to the experiment On-site Spokesperson and the local beamline Laser Safety Officer


  • ANL-ESH Section 6.2, Rev. 3, Laboratory-wide Procedure; Nonionizing Radiation Protection - Laser Safety

Reviewed April 16,213