4. Hazard Classifications
- Class 1:
Any laser product which does not permit human access to laser radiation in excess of the accessible emission limits of Class 1 for applicable wavelengths and emission durations.Class 1 lasers are the lowest powered lasers and considered "harmless" unless tampering with the device has occurred. An example of a Class 1 laser product is a CD-ROM player.
- Class 1M:
Any laser product having large beam diameter or large beam divergence, in the wavelength range from 302.5 nm to 4000 nm, which does not permit human access to laser radiation in excess of the accessible emission limit of Class 1.These lasers are considered "non-hazardous," but could become hazardous if viewed by optical instruments (magnifier or telescope).
- Class 2:
Class 2 lasers are low-powered lasers that emit in the visible spectral range, where eye protection is normally afforded by the aversion response.This class could constitute a hazard, if one intentionally stares into the beam. An example of a Class 2 laser is a supermarket checkout scanner.
- Class 2M:
Any laser that emits in the visible spectral range, and has large beam diameter or large beam divergence, which does not permit human access to laser radiation in excess of the accessible emission limit of Class 2.These lasers are considered "non-hazardous," but could become hazardous if viewed by optical instruments (magnifier or telescope).
- Class 3R:
Class 3R lasers are semi-medium-powered lasers that could pose a mild ocular hazard if the laser light is viewed directly.Many laser pointers used during lectures are Class 3R lasers.
- Class 3B:
Class 3B lasers are medium-powered lasers and pose an ocular hazard when the beam is viewed directly.
- Class 4:
Class 4 lasers are high-powered lasers (>0.5 W in power or >125 kJ per pulse) that pose an ocular hazard not only via the direct laser beam, but also from diffuse reflections.Class 4 lasers also pose a hazard to skin and can cause fires. Class 4 is the most hazardous class.