Some information from The National Radiological Protection
Board
Use of lasers and training
The British Standard provides advice on the use of lasers
and states that only Class 1 or Class 2 devices should be
used in unsupervised areas
Laser pointers used by, for example, professional
lecturers in the workplace are considered to fall under
this category. Minimum training requirements are specified
for operators using lasers of a higher Class for these
purposes due to the risk of eye injury.
Such training should include guidance to the user on the
risks from the laser beam and advice not to point the beam
at anyone.
Class 1 lasers are products where the radiant power of the
laser beam is always below the Maximum Permissible
Exposure value. Therefore, for Class 1 lasers the output
power is below the level at which it is believed eye
damage will occur. Class 1 laser products may contain
laser systems of a higher Class. Examples of such products
include laser printers and compact disc players.
Class 2 lasers are limited to a maximum output power of 1
milliwatt and the beam must have a wavelength between 400
and 700 nm.
A person receiving an eye exposure from a Class 2 laser
beam, either accidentally or as a result of someone else's
deliberate action (misuse) will be protected from injury
by their own natural aversion response. Repeated,
deliberate exposure to the laser beam may not be safe.
Some laser pointers and barcode scanners are Class 2 laser
products.
Laser pointers currently available on the market
NRPB has examined several laser pointers currently
available to the general public in order to assess their
laser Class and have found a significant proportion of
these products to be Class 3R lasers and several Class 3B.
The body's natural aversion responses are unlikely to
provide adequate protection from eye injury for Class 3B
laser pointers.
Class 3R lasers have a maximum output power of 5 mW or 5
times the Accessible Emission Limit (AEL) for a Class 1
product. The laser beams from these products exceed the
maximum permissible exposure for accidental viewing and
can potentially cause eye injuries.
Examples of Class 3R products include some laser pointers
and some alignment products used for home improvement work.
Green laser pointers have given a particular cause for
concern. Many of these are not even suitable for
professional use because they cause afterimages in people
viewing the beam on a projection screen.
Although the risk of a permanent eye injury from a laser
pointer may be small, an individual receiving even a
transient eye exposure from a laser pointer will
experience a bright flash, a dazzling effect, which is
likely to cause distraction and temporary loss of vision
in the affected eye and possibly after-images.
Many of the laser pointers assessed by NRPB were either
incorrectly labelled or not labelled at all. It was also
unusual to find any information on laser safety and
warnings on the implications of potential misuse supplied
with the products.
NRPB advises that the sale of laser products to the
general public for use as laser pointers should be
restricted to Class 1 or Class 2 and should be sold with
sufficient accompanying information to enable the user to
operate the product in a safe manner.
After seeking advice from NRPB the Department of Trade and
Industry has urged Trading Standards Authorities to use
their existing powers under the General Product Safety
Regulations 1994 to remove laser pointers of a Class
higher than Class 2 from the general market. Such devices
are too powerful for general use as laser pointers and
present an unacceptable risk in the hands of the consumer
because they may cause eye injury in normal reasonably
foreseeable use.
Only three of the many sites that give useful information
on laser pointer safety
www.nrpb.org
www.hc-sc.gc.ca/english/iyh/products/laser.html
http://www.rli.com/resources/pointer.asp