Lasers are a potential safety hazard in the laboratory, and Duke’s Laser Safety Program is designed to address that hazard, specifically for Class 3b and Class 4 lasers, which pose the most serious risks. Under Duke policy, a faculty member responsible for such a laser is called a Principal Laser User (PLU^*). The PLU^* is directly responsible for the safe use of the lasers under his or her control, and must complete the online Laser Registration Form for each Class 3b or Class 4 laser.