CDRH

All manufacturers of lasers used in the United States must conform to regulations administered by the Center for Devices and Radiological Health (CDRH), a branch of the U.S. Department of Health and Human Services. CDRH categorizes lasers as follows: 

Class 1 – Incapable of causing injury during normal operation

Class 1M – Incapable of injury unless collecting optics are used

Class 2 – Visible lasers incapable of causing injury in 0.25 s

Class 2M – Visible lasers incapable of causing injury in 0.25 s unless collecting optics are used

Class 3R – Marginally unsafe for intrabeam viewing; up to 5 times the class 2 limit for visible lasers or 5 times the class 1 limit for invisible lasers

Class 3B – Eye hazard for intrabeam viewing

Class 4 – Eye and skin hazard for both direct and scattered exposure.