Laser technology is increasingly being used in workplaces. Lasers can be hazardous if appropriate controls and safe systems of work are not used.
Scope of the problem
Laser beams may cause damage to eyes or skin. The risk of eye injury from laser light and heat is particularly of concern as eyes focus and intensify light entering them. Repeated exposure to relatively low powered lasers, or from a single exposure to medium powered lasers may cause long term damage to sight or minor damage to skin. Exposure to high level lasers may cause depigmentation, severe burns and possible damage to underlying organs. High-powered lasers may also cause fire hazards.
Lasers may produce hazards from airborne contaminants released during laser use, collateral radiation, high voltage electricity, cryogenic coolants and flying particles during laser cutting or welding.
Industrial lasers are used for cutting and welding. Many different types of scientific lasers are used in a wide range of applications. Medical lasers are used on eyes and for microsurgery, neurosurgery and dermatology. Lasers are used in optical fibres and for display and entertainment, instrumentation, security systems, surveying and alignment, optical radar, holography and even in toys.
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 sufficient protection is given 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. Even diffuse reflections of Class 4 lasers are hazardous to eyes, and the direct beam is a fire hazard and serious skin hazard.
Western Australian legal requirements
The Occupational Safety and Health Regulations 1996 require that employers, main contractors and self-employed persons ensure lasers or laser products are not operated at a workplace unless classified and labelled in accordance with AS 2211. Class 3B or Class 4 lasers or laser products (as defined in AS 2211) must not be used for construction work. Other lasers and laser products used in construction work must be in accordance with AS 2397. Lasers and laser products used at workplaces other than construction sites must be in accordance with AS 2211 (Reg. 4.49).
Lasers are also subject to the Western Australian Radiation Safety Act administered by the Department of Health. Some types of high powered lasers must be registered under this Act.
Competent persons must identify hazards and assess risks before lasers are first used. They should consider suitability of the laser type, the capability of the laser to injure people, the environment in which the laser is used, and operator training.
Where there is a risk to health and safety from laser use, employers should consider (in order of preference):
- eliminating laser use;
- substituting with a safer alternative;
- isolating the laser - a closed laser operation should be used where practicable;
- engineering controls - interlocks, workplace layout, shielding materials and warning signs;
- administrative controls - procedural and administrative control methods should ensure exposure limits are not exceeded; and
- personal protective equipment - eye protection and skin protection should be designed for the specific wavelength and power of the laser system used.
At all times, people should avoid looking into a laser beam or a laser reflection, even if the exposure limit is not exceeded.
Lasers should be used in a controlled area, with special emphasis given to controlling the path of the laser beam. Only authorised personnel should operate lasers and spectators should not be allowed to enter controlled areas unless appropriate supervisory and protective measures are applied. Optical systems such as lenses, telescopes and microscopes may increase the hazard to the eye. Special care should be taken with their use and an interlock or filter may be needed. Only Class 1 and 2 lasers may be used for displays or entertainment in unsupervised areas.
Laser pointers, used in presentations as remote pointing devices for slides, overheads and computer projections, must not exceed Class 2. The improper use of laser pointers in social situations such as nightclubs may be hazardous and can cause temporary blindness, disorientation or permanent and serious ulcers when shone directly in people's eyes.
Operators of Class 3 and Class 4 lasers should be trained as required by Australian Standard 2211.
Workplace laser surveillance and health surveillance should be used to ensure safe use of lasers is maintained in the workplace and employee exposure levels are not exceeded.
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