I. Introduction:
A. Purpose of Guideline:
This guideline is designed to provide a general overview to lasers,
laser uses, laser hazards and hazards analysis that are required
to provide appropriate background for understanding the applicable
industry standards and regulatory requirements.
B. Use of Guide:
The guide is divided into eleven topical sections. Sections I
to III provide background information on laser and laser beams,
laser bioeffects and ancillary hazards.
Pertinent definitions are in the glossary in Appendix A. Sections
IV to VI cover the aspects of laser standards, classifications
and overall hazard analysis. Sections VII and VIII review laser
controls and protective equipment. Section IX covers training
requirement. A comprehensive reference listing is provided in
Section X.
In general, each section is designed to cover one major aspect
of the laser story and can be reviewed separately from the balance
of the review. There is, of course, some need to have understanding
of the earlier sections to fully apply information in the later
sections, especially Section VII on laser hazard evaluation.
C. Who Uses Lasers?
Estimates of the number of workers involved on a routine basis
with laser devises are difficult to perform. One method to estimate
the number of workers is through the number of subscribers to
the various laser related trade magazines. Estimates indicate
that the number of non-overlapping subscribers to the three major
laser/electro-optics magazines is approximately sixty thousand.
This number is based upon a comparative evaluation of the total
number of subscribers for each magazine using sample statistical
information for the number of non-overlapping subscribers.
It should be stressed that these are controlled circulation magazines
and are received by only 10-30% of the individuals at each facility
involved with laser and electro-optics activities. Hence, one
can estimate, using a multiplier ranging from three to ten, that
the "total" laser worker universe in the early 1980's
ranges from 180,000 to 600,000 people. Using estimates of the
projected growth over the next decade of 20% to 25% per year,
one can project a total laser-worker universe total in the early
1990's ranging from 520,000 to perhaps as high as 6,000,000 people.
A NIOSH report estimated that by 1980 about 9 million workers
would have been potentially exposed to lasers and different arcs.
These results were based upon U.S. Census Bureau estimates and
other Government reports.
If it is assumed that only 60% of the workers are potentially
exposed to arcs alone, this would mean that 3.6 million workers
are potentially exposed to lasers alone. This estimate is of the
same basic magnitude as the estimate obtained previously (0.5
to 6 million) based upon magazine subscription data. Comparison
of these two estimates permits the general conclusion that one
can, with some certainty, conservatively project in excess of
one million workers involved with the applications of lasers by
the mid-to-late 1990's.
This would indicate that the potential for accidental exposures
to laser radiation will shift from the developmental engineer
and scientist group (where a high percentage of the previous incidents
have occurred) to the general occupational work force. One might
wonder how many more incidents will occur with this shift to personnel
who are much less aware of laser damages?
D. Laser Applications:
The following will review some of the more important laser applications
and types of lasers used. Emphasis will be placed upon those lasers
with the largest number of applications and, hence, involve the
largest number of workers.
All of this indicates that potential for exposure to laser light
has expanded beyond the scientific laboratory and workplace into
the entertainment arena, museum, public building lighting, and
even the home.
E. Projections for the 1990s:
The current scope of laser applications is certainly extraordinary.
Virtually every industry group is represented. The question to
be asked is, perhaps, "WHAT NEW AREAS OF LASER APPLICATIONS
WILL BE EXPLORED IN THE NEXT DECADE?"
First, there will be the normal extension of the current applications
across industry lines. Also, the use of higher power systems to
serve multiple work stations on a beam time sharing basis will
become more common. Most laser devices will be dedicated systems,
designed for a specific application.
New applications will most probably center on the use of tunable
wavelength and ultraviolet laser devices (perhaps a second generation
of excimer lasers). This lends itself to photochemistry and/or
photobiological work where the need for a specific wavelength(s)
is paramount for the application.
Medical applications will be expanded with the use of various
adjuvants with the treatments. For example: dye injections will
be administered to the patient which are selectively absorbed
in tumors to enhance the selective absorption of laser energy
in the tissues and provide a more specific therapy.
The uses of lasers with fiber optics will include, in addition
to communications - which could become the singularly largest
application area of all laser uses - more uses in the industrial
laser area. For example, the natural extension of laser materials
processing would be the incorporation of laser fiber optics to
conduct the beam to remote places as in the field of robotics.
All other new applications will bring certain unknowns from a
laser hazard and overall occupational health point of view. For
example, development of the Free Electron Laser (FEL), although
now located at only a few isolated research centers, has combined
electron accelerator, high magnetic field and tunable laser technology
together in a single installation. In addition, research is underway
for lasers to emit in the X-ray spectrum. All of these developments
implies that the hazards associated with laser facilities will
most probably be more complex in the future.
In addition, it is most probable that the use of the laser with
new procedures and processes will produce new and, perhaps, unknown
substances that can present new hazards. It will be necessary,
therefore that each of these new applications areas be approached
with some caution and that the laser interaction be studied and,
where hazards are identified, methods of control be established.
Guidelines for Laser Safety and Hazard Assessment
Source: Occupational Safety & Health Administration, Guidelines
for Laser Safety and Hazard Assessment PUB 8-1.7 (tablular data
and equation illustrations have been omitted).
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