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).