A Laser Safety Guide
The following is a summary of the new classifications for laser safety, for a definitive
guide please refer to the International Electrotechnical Commission (IEC) 60825-1
standard – Safety of laser products Part 1: Equipment classification, requirements and
user’s guide adopted within Europe as EN60825-1. This is the internationally approved
laser safety standard.
Class I – No risk to eyes or skin
Class 1 laser products are defined as safe under the majority of working conditions,
including direct viewing of the laser beam with focusing optics.
Examples: Low power lasers
Totally enclosed higher power lasers e.g. CD players and laser printers
Class I M – Low risk to eyes and skin
Class 1M laser products are defined as safe under the majority of working conditions,
including direct viewing of the laser beam provided the user does not employ focusing
optics e.g. binoculars.
The safety standard limits the consideration of viewing aids to laser wavelengths in the
range at which silica optics transmit i.e. 0.3 – 4 m.
Class 2 – Low risk to eyes, no risk to skin
These lasers are defined as those emitting visible light for which the natural aversion
response prevents any damage to the users retina. This includes viewing of these lasers
with concentrating optics.
Safety standard accessible emission limits:
1mW for a continuous wave laser (visible or invisible)
Class 2 M - Low risk to eyes, no risk to skin
This classification covers lasers capable of emitting visible light for which the natural
aversion response prevents any damage to the users retina as with class 2, but in this case
only provided the user does not view the laser beam through focusing optics.
Safety standard accessible emission limits:
1mW for a continuous wave laser (visible or invisible)
Class 3 R – Low risk to eyes, low risk to skin
Class 3R lasers are defined as those whose output power is up to a factor of 5 greater than
that of class 1 or class 2 lasers. The risk of injury from direct viewing is still low but
much greater efforts should be made to prevent direct eye exposure. This is especially
true for the invisible class 3R lasers.
Safety standard accessible emission limits:
5mW for a continuous wave visible laser
Class 3 B – Medium risk to eyes, low risk to skin
Class 3B laser products are defined as those that are hazardous to the eye on direct
exposure, even taking aversion responses into account. In this class scattered light from
these laser sources in usually considered safe. The higher powered class 3B lasers are
also a potential skin hazard, however, the natural aversion response to localized heating
prevents the skin from burning.
Safety standard accessible emission limits:
500mW for a continuous wave laser (visible or IR)
Class 4 – High risk to eyes and skin
Class 4 lasers are defined, as those for which direct exposure to skin and eyes is
hazardous, scattered light may also be hazardous. These lasers are also classed as fire
hazards.