What are lasers?
Lasers were developed out of post World War 2 technology. Some types of laser equipment are now used in industry.
'Laser' means light amplification by stimulated emission of radiation. Lasers produce visible and invisible (ultraviolet and infrared) radiation in the non-ionizing portion of the electromagnetic spectrum. Lasers are made up of electromagnetic waves of the same wavelength and frequency that travel in one direction and are monochromatic (one colour). Thus lasers are referred to as coherent light.
As with all workplace hazards, the hazard should be dealt with in this way:
- Identification of the hazard (see more information, below)
- Assessment of the risk
- Elimination or reduction of the risk
- Review and evaluation of any control strategies
Laser hazard controls should be designed to eliminate or minimize potential eye hazards resulting from a direct laser beam or a reflection of the beam, and skin burns. Employers should use proper engineering controls to eliminate/minimize harmful occupational exposures. Engineering controls may depend on whether the laser equipment is in or outdoors. As required, backstops and shields should be used to protect workers from possible exposure.
In addition, employers must provide all workers who operate and/or are exposed to laser equipment with information and training on the potential hazards of lasers. Only trained workers should work with or near laser equipment.
Employers should also:
- provide with necessary personal protective equipment such as gloves, goggles, aprons, and clothing;
- label all laser equipment to indicate the type of laser and potential eye and skin hazards;
- ensure all surfaces in the laser area are non-reflective. The work area should be brightly lit to prevent the dilation of the pupils;
- store all flammable materials in proper containers and shield then from the laser beam;
- safeguard all electrical hazards;
- where possible, have audible signals to indicate when the laser equipment is in operation; and
- establish and maintain effective maintenance programs.
Employers should establish a medical surveillance program for workers working with or around laser equipment. Such a program would consist of a pre-placement medical examination, a follow-up annual exam, and an exam upon completion of employment. Medical examinations should include complete opthamologic and dermatologic tests as well as a review of the worker's medical history.
Information obtained from these medical examination would allow for accurate detection and documentation of medical problems. Medical information and test results should be made available to all employees upon request.
OHS reps should make sure that their employer is maintaining a safe and healthy workplace. The key to making the workplace safe for workers is a strong, active membership, reps and OHS committee.
Industrial lasers are used for cutting and welding. Scientific lasers are used in a wide range of applications. Medical lasers are used on eyes for microsurgery, neurosurgery and dermatology. Lasers are used in optical fibres and display and entertainment, instrumentation, security systems, surveying and alignment, optical radar, holography and toys.
There are three types of laser beam generating media solid-state, gaseous state, and semi-conductor.
- Solid-state lasers are used in such operations as tunneling and mining. The most common type of solid state laser is the ruby crystal.
- Gaseous state lasers, such as a helium neon laser, are most widely utilized in the construction industry for the purpose of establishing a reference line for dredging, tunnelling, pipe-laying, bridge building, and marine construction equipment.
- Semi-conductor lasers are most widely used in the transmission of communications signals. Because of the inability of semi-conductor laser beams to penetrate fog, rain, or snow very well, they are enclosed within telecommunications cables.
In addition, solid state and gaseous state laser technology is widely used in the health care industry.
What workers are likely to come into contact with lasers?
- Workers in the telecommunications industry, in the form of fibre optic cables introduced at an increasing rate due to the fact that laser equipment can carry many more communications messages than lead and polyurethane-encased cables.
- Workers in the health care field, where laser medical devices are being widely introduced and used for enhanced medical treatment.
- Medical workers who use laser components or test equipment may be exposed to potentially hazardous laser equipment.
- Workers employed as lightguide manufacturing workers, installers, outside plant technicians, cable splicers, and service technicians.
- Workers at construction sites.
What are the potential hazards associated with lasers?Lasers are rated by hazard classification, according to their ability to injure people.
- Class 1 lasers are not hazardous.
- Class 2 lasers are normally not hazardous as enough protection is provided by 'normal aversion responses' - the eye's automatic reflex to blink and look away from bright or sudden light exposure
- Class 3 lasers are hazardous where eyes are exposed to direct laser beams or laser light from reflective surfaces.
- Class 4 lasers, and even diffuse reflections of these lasers, are hazardous to eyes, and the direct beam is a fire hazard and serious skin hazard.
Direct eye exposure to all lasers should be avoided. Where possible, the Class 4 laser beam path should be controlled. When the beam path is not enclosed, a safety latch or interlock system should be used. Such a system would prevent operation unless the laser equipment is furnished with the proper enclosures.
Lasers and laser equipment may be potentially hazardous to the eyes and skin. The degree of risk depends upon the type of laser beam, the frequency or power of the laser, beam divergence, as well as intensity and duration of exposure.
The eye is the most susceptible to laser radiation. When exposed, the cornea and the lens of the eye (located at the front of the eye) magnify and focus the radiation on the retina (located at the back of the eye). Direct exposure to a laser beam or a reflection of a laser beam can burn the retina causing partial or complete blindness. When a worker suffers eye damage, he/she should have an eye examination as soon as possible. Factors determining the amount of damage to the eye include:
- the reaction of the cornea and lens,
- the presence or absence of reflective materials between the laser source and the eye, and
- the distance from the laser to the retina.
When working with lasers or laser equipment, optical aids like microscopes and binoculars should not be used (unless beam intensities are so low as to be absolutely safe) because these magnify the laser beam, increasing the intensity of the beam.
Laser radiation may cause mild reddening and swelling, blistering, or charring of skin. The degree of harm is dependent upon the duration of exposure, radiation wavelength and the amount of radiation absorbed.
In addition, the health hazard of electrical shock exists if workers are working with high voltage laser transmission components. Highly-powered lasers also set off electrical discharges into the atmosphere, emitting ozone. Hazardous exposure to ozone may result in eye and upper respiratory irritation.
Workers employed as lightguide manufacturing workers are exposed to hazards in addition to those associated with lasers: they also are exposed to a variety of toxic chemicals and solvents, broken glass, electrical hazards, working on ladders and platforms, microwave and radio frequency radiation hazards, substances which can cause severe burns, potential air contaminant hazards from chemical spills, and "fibre whip".
In Victoria, lasers are regulated under Part 3.5 (Plant) of the Occupational Health and Safety Regulations, 2017. The regulations specify duties relevant to designers, manufacturers, suppliers and importers of plant such as lasers, as well as duties of employers. The specific duties under the regulations of the employer with regard to plant such as lasers are:
- to undertake hazard and risks identification
- to control any risks identified, according to the hierarchy of control - that is elimination if practicable, followed by substitution, engineering controls or isolation, in that order
- duties with relation to guarding, installation and use of plant
- to provide training, information and instruction to employees
- to consult with elected OHS reps.
The Compliance Code for Plant has not yet been developed, but the old Code of Practice for Plant, provided more detailed advice and references the following technical standards relevant to the design, manufacture and use of lasers:
- AS 2211 - (a number of parts) Safety of Laser Products
- AS 2397 - Safe use of lasers in the building and construction industry
- I/C 825 - Safety of laser products
- EN 60825 - Specification for radiation safety of laser products, equipment classification, requirements and user's guide
The old Code of Practice [pdf] can still be accessed from the WorkSafe Victoria website.
There are more Australian standards on Lasers, such as:
- AS/NZS ISO 11553:2004 Safety of machinery - Laser processing machines - Safety requirements
- AS/NZS ISO 11990:2002 Optics and optical instruments - Lasers and laser-related equipment - Determination of laser resistance of tracheal tube shafts
- AS/NZS 1337 (a number of parts) on Eye and face protection - Filters and eye protectors
- AS 2397-1993 Safe use of lasers in the building and construction industry
- AS/NZS 4173:2004 Guide to the safe use of lasers in health care
All Australian/NZ and international standards can be purchased from the SAI Global website.
- SafetyLine Essentials: Laser Safety from Work Safe WA.
- Safe Work Australia Fact sheet: Laser classification and potential hazards provides guidance about the system of classification of laser devices and the potential hazards of the laser classes.
- Communication Worker Union of America - Fact Sheet #17: Lasers and the workplace. Thank you!
- Work Safe WA SafetyLine Essentials: Laser Hazards
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Last amended March 2015