Laser Safety

LASER PERFORMANCE STANDARD: 21CFR 1040

Lasers are classified according to the Accessible Emission Level (AEL)

Power Output

Class I (a) and ( b)	0.0004 W
Class II (a) and (b)	0.001 W
Class III (a) and (b)	0.005 W
Class IV	>0.5 W to 100 W

Hazards depend on:

a) Power output; b) Beam Diameter; c) Path Divergence;
d) Pulse Length; e) Wavelength; f) Exposure

Hazards are:

Beam Related Hazards:

Thermal Injury: Mild or irreversible damage burns when exposure is more than 0.000001sec and the wavelength is near UV to far IR (0.315 to 10 pm).
Ocular Injury: Effect on different structures of the eye. Wavelength: 0.4 to 1,400 pm.

Industrial Hygiene Hazards

Gases produced, noise, ionization radiation.

Warnings

Class I - These low power lasers require no control measures to prevent eye damage. These lasers emit levels below the AEL.

Class II - These lasers are not considered hazardous for momentary (0.25 sec) and unintentional direct viewing of the laser beam, but it must not be aimed deliberately at anyone's eyes.

Class IIa lasers must be labeled: Class IIA Laser Product - Avoid Long -Term Viewing of Direct Laser Radiation. A label must be afixed to the unit with the words Laser Radiation - Do Not Stare Into Beam. Maximum output of laser radiation, pulse duration and laser medium or emitted wavelength(s) must be also on the label.

Class III - These lasers are hazardous to the eyes if the direct beam is looked at directly or at specular reflections of the beam.

Class IIIa units must have a label affixed to the unit with the words Laser Radiation - Do Not Stare Into Beam or View Directly With optical Instruments. Class IIIa Laser Product.

Class IIIb units would use a label with the words Laser Radiation - Avoid Direct Exposure to the Beam. Class IIIb Laser Product. Mirror-like smooth surfaces of any material that would reflect the beam as a beam should be eliminated as much as possible from the area in which the laser is situated. The room must be kept locked to prevent others to accidentally changing the physical configuration or exposing their eyes to the beam. If there is danger of direct or reflected exposure to the beam, eye protection must be worn. Class IIIb lasers follow the same safety practices as Class IV lasers.

Class IV - These lasers require many safety precautions to be used safely. The eyes and skin can be injured. Some can provide enough energy to cause a fire in combustible materials. A label must be affixed with the words Laser Radiation - Avoid Eye or Skin Exposure to Direct or Scattered Radiation. Class IV Laser Product.

References:

CRC Handbook of Laboratory Safety

Laser Safety Related Resources