Laser Saftey

<sup><sub>Types of hazards include:
1. Eye: Acute exposure of the eye to lasers of certain wavelengths and power
can cause corneal or retinal burns (or both). Chronic exposure to excessive
levels may cause corneal or lenticular opacities (cataracts) or retinal
injury.
2. Skin: Acute exposure to high levels of optical radiation may cause skin
burns; while carcinogenesis may occur for ultraviolet and near ultraviolet
wavelengths.
3. Chemical: Some lasers require hazardous or toxic substances to operate
(i.e., chemical dye, Excimer lasers).
4. Electric shock: Most lasers produce high voltages that can be lethal.
5. Fire hazards: The solvents used in dye lasers are flammable. High voltage
pulse or flash lamps may cause ignition. Flammable materials may be
ignited by direct beams or specula reflections from high power continuous
wave (CW) infrared lasers.</sub></sup>

<sup><sub>Lasers are generally classified and controlled according to the following
criteria:
1. Class 1: Low-power lasers and laser systems that cannot emit laser
radiation levels greater than the Maximum Permissible Exposure (MPE).
Class 1 lasers and laser systems are incapable of causing eye damage and
are therefore exempt from any control measures.
2. Class 2: Visible, low power lasers or laser systems that are incapable of
causing eye damage unless they are viewed directly for an extended period
(greater than 1000 seconds). See Table 4 for laser pointers.
3. Class 3: Medium-power lasers and laser systems capable of causing eye
damage with short-duration (<0.25 s) exposures to the direct or specularly
reflected beam. Includes Class 3a and 3b lasers.
4. Class 3a: Lasers or laser systems that normally would not produce a
hazard if viewed for only momentary periods with the unaided eye. They
may present a hazard if viewed using collecting optics. See Table 4 for
laser pointers.
5. Class 3b: Laser or laser systems that can produce a hazard if viewed
directly. This includes intrabeam viewing or specular reflections.
6. Class 4: High power lasers and laser systems capable of causing severe
eye damage with short-duration (<0.25 s) exposures to the direct,
specularly reflected, or diffusely reflected beam. Class 4 lasers and laser
systems are also capable of causing severe skin damage and igniting
flammable and combustible materials.</sub></sup>

<sup><sub>General Laser Safety Recommendations and Requirements
1 Eye Protection: Principal Investigators or staff who operate or supervise the
operation of a laser are responsible for determining the need for laser eye
protection for a particular laser. If required, eye protection will be provided by the
supervisor for staff and visitors to the area. The booklet "Guide for Selection of
Laser Eye Protection: produced by the Laser Institute of America may provide
assistance in eyewear selection. Check with your Principal Investigator or OH&S
for a copy.
2 The minimum laser radiant energy or laser power level required for the
application should always be used.
3 Beam Control: To minimize direct eye exposure, observe these precautions:
1. Do not intentionally look directly into the laser beam or at a specular
reflection, regardless of its power.
2. Terminate the beam path at the end of its useful path.
3. Locate the beam path at a point other than eye level when standing or
when sitting at a desk.
4. Orient the laser so that the beam is not directed toward entry doors or
aisles.
5. Minimize specular reflections.
6. Securely mount the laser system on a stable platform to maintain the beam
in a fixed position during operation and limit beam traverse during
adjustments.
7. Confine primary beams and dangerous reflections to the optical table.
8. Clearly identify beam paths and ensure that they do not cross populated
areas or traffic paths.
9. When the beam path is not totally enclosed, locate the laser system so that
the beam will be outside the normal eye-level range, which is between 1.2
to 2 meters from the floor. A beam path that exits from a controlled area
must be enclosed where the beam irradiance exceeds the MPE.</sub></sup>

^{_{Each laser and laser facility must be designed to ensure that maximum protection is afforded to the
operator.
Only Class I, Class II, and Class IIIa lasers may be used for demonstration purposes.
Class I lasers require no controls.
Class II lasers require the following controls:
·  The protective housing must be provided for all lasers.
·  A Class II "Caution" logo must be posted on the laser and must read "Do Not Stare Into The
Beam".
·  The laser beam must never be intentionally stared into or directed into the eye.
Class IIIa lasers require the following controls:
·  The appropriate "Caution" label must be affixed to the protective housing.
·  Each laser area must be posted with the appropriate "Caution" sign.
·  Any protective housing must remain in place to prevent exposure to radiation from any source
other than the defined aperture unless the protective housing interferes with necessary laser
operation.
·  The protective housing must be interlocked to prevent exposure of personnel to unnecessary laser
radiation. Interlocks must be checked during routine inspections to ensure they are functioning
properly. The interlock must not be overridden during normal operation.
·  Beam stops for lasers must be permanently attached and be capable of preventing access to
unnecessary laser radiation.
·  Since viewing portals and collecting optics may increase the hazards, all devices must incorporate a
means to maintain laser radiation emitted through them at or below safe levels. The laser safety
officer or the principal investigator is responsible for determining the hazard involved and is
responsible for taking the proper safety measures. Equipment labels must be properly displayed on
each laser and must include the class of laser, power output, and the appropriate cautionary
statement.
·  Each laboratory must keep written operating, alignment, safety, and emergency procedures.
Copies of these documents must be submitted to the Radiation Safety Office upon request. Any
changes to any of these procedures must be forwarded to the Radiation Safety Office upon
request.
Class IIIb and Class IV lasers require the following controls in addition to requirements needed with
Class IIIa lasers:
·  The appropriate "Danger" label must be affixed to the protective housing;
·  All protective housings and service panels needing removal for maintenance must have labels
indicating defeatable interlocks.
·  If the interlocks must be bypassed during maintenance, a temporary Laser Control Area must be
established (see below).
·  A master switch (either a key or coded access) must be provided that, when removed, must make
the laser inoperable. Authority for access to the master switch must be with the principal
investigator and/or the laboratory laser safety officer.
·  Beam paths must be oriented so that totally unenclosed and partially enclosed beams are operated
only in specific laser controlled areas established by the principal investigator and the laboratory
laser safety officer in conjunction with the Radiation Safety Office.
A laser controlled area for Class IIIb and IV lasers must meet the following criteria:
·  A Laser Control Area must be under the direct supervision of the laboratory laser safety officer.
·  The Laser Control Area must be posted with appropriate warning signs.
·  Hazardous beams must terminate in an appropriate beam stop.
·  Except as required for medical use, the laser beam path must be configured such that the exposed
beam is above eye level of a person in standing position or below eye level of a person in seated
position. Example: The beam path remains 6.5 feet and below 3.5 feet off the floor.
·  Only diffusely reflecting materials may be near the beam path.
·  Effective eye protection must be available and worn by all individuals who have access to the laser
radiation.
·  All openings (windows, doors) from the Laser Control Area must be covered or restricted to
prevent unnecessary exposure to laser radiation.
·  There must be a visual or audible indicator that is activated prior to emission of the beam.
·  Remote firing with video monitoring or other remote viewing techniques must be chosen when
feasible.
·  Backstops must be constructed of diffusely reflecting material and, when practical, fire resistant
material.}}