What class of laser is considered the least hazardous?

Class 1 lasers are considered the least hazardous because they are designed to be safe under all conditions of normal use. This includes lasers embedded in equipment where they cannot be accessed by the user or where the power output is so low that even direct exposure to the beam presents no risk of injury to the eye or skin. Class 1 lasers include devices such as laser printers and CD players, which operate at levels that do not pose a hazard even when viewed directly.

In contrast, as the class number increases, the potential hazards associated with the lasers also increase, leading to different safety regulations and precautions. Class 2 lasers can cause harm with prolonged exposure, while Class 3A and Class 3B lasers present more significant risks and require more stringent safety measures to protect users from potential eye damage or burns. Therefore, Class 1 lasers stand out as the safest category, making them the least hazardous option among the choices provided.