Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.
The term "laser" stands for "light amplification by stimulated emission of radiation". Laser light is a form of non-ionizing radiation.
Lasers play a role in virtually every workplace in Ontario. A worker may be exposed to lasers while scanning a bar code, performing a medical procedure in a medical or veterinary practice, monitoring a machine cutting through metals, ceramics, plastics, or multiple thicknesses of cloth, levelling a beam in a construction project, setting up an entertainment show, conducting research or performing a cosmetic procedure on a client.
Lasers produce a very powerful beam of optical radiation. The beam may travel long distances while retaining its ability to do useful work…or to injure a worker!
A worker exposed to a direct or reflected laser beam may suffer an injury to the eye and/or the skin. In addition to the hazards associated with exposure to the laser beam itself, there are non-beam hazards associated with the use of lasers. Examples include the risk of electric shock or electrocution when working with high voltage electricity, health hazards from exposure to contaminants found in the laser plume and the potential for fire when the direct or reflected laser beam strikes a combustible material.
The province of Ontario, under the general duty clause 25(2) (h) of the Occupational Health and Safety Act (OHSA), requires employers to take every precaution reasonable in the circumstances for the protection of a worker. This includes the protection of workers from the hazards associated with lasers. When enforcing the general duty clause under OHSA, the Ontario Ministry of Labour’s Radiation Protection Service takes into consideration the American National Standards Institute (ANSI) Z136 series of laser safety standards (the "ANSI" Standards) and for medical applications, CSA Z383-14 – Safe Use of Lasers in Health Care Facilities.
A complete listing of the relevant standards can be found in the Standards section at the end of this document.
The hazard posed by a laser relates to its potential to injure workplace parties, the environment in which the laser is located, and the knowledge, training and work practices of the workers concerned.
The laser’s output power, its wavelength(s), beam diameter, output optics, mode (continuous or pulsed), and the physical geometry of the beam as it relates to workers nearby are the most important characteristics in determining the degree of danger the laser presents. Because of the technical complexity of these factors, lasers and laser systems are categorized into classes. The classifications categorize lasers according to their ability to produce damage in exposed people, from class 1 (no hazard during normal use) to class 4 (severe hazard for eyes and skin). The safety requirements are linked to the laser classification. Manufacturers and importers are required by law to classify and label lasers.
Note: Health Canada’s Radiation Protection Bureau controls the sale, lease and import of lasers, as per the Radiation Emitting Devices Act and lasers and laser systems must meet the requirements of the Radiation Emitting Devices Act.
The employer must know the class of each laser and laser system used, which can be found on the label of each laser system or in the user manual.
A summary of the laser classification system and some of the key elements of the ANSI Standards on laser safety can be found below.
For more information on appropriate protections associated with each class of laser, Table 10 in ANSI Standard Z136.1 (PDF) provides a convenient summary of the safety requirements of that standard.
Containment (as one of the top hierarchy of engineered controls) of the hazard is preferred and very often less expensive than providing workers with protective devices, advanced training, and ongoing close supervision. Class 3B and Class 4 lasers are often found in a protective enclosure so that the laser system (the laser and its enclosure with required safety features) are Class 1 devices. Unless the enclosure is breached, as may occur during alignment, servicing, etc., the safety requirements for these devices in the ANSI Standard are as for a Class 1 device.
When considering hazards associated with a laser beam, one must be aware that different wavelengths of light have different properties. For example, materials that appear dull or opaque in visible light may be perfect mirrors or transparent in the infrared band. The human eye is insensitive to near infrared light (a very powerful and damaging near-infrared beam may appear as a dull red glow).
A laser may injure a worker through a number of mechanisms. At low intensities, and/or with prolonged use, the laser can "bleach" the colour receptors in the eye, causing loss of colour vision. The laser beam may burn the surface of the skin or eye (the eye is particularly susceptible to damage). For visible light lasers (commonly used in cosmetic procedures) and for near-infrared lasers, the lens of the eye can focus the laser beam onto a point at the back of the eye in the same manner as a magnifying glass can focus the sun’s rays. In this manner, even small lasers (e.g., laser pointers) can cause permanent damage if misused. Pulsed lasers may cause micro-explosions in tissue; the resulting shock waves can damage cells leading to loss of vision and skin lesions.
In all cases of suspected injury, medical attention should be given immediately and the supervisor and employer informed as soon as possible. A worker briefly exposed to a low powered laser (Class 1 to 3R) beam may experience "flash blindness." Though no permanent injury may result, temporary loss of useful vision or a startle reaction may cause secondary effects. For example, a lift-truck operator struck with a bar-code scanner beam could be involved in a workplace collision.
In certain circumstances, workplace parties have legal obligations to notify the Ministry of Labour and the Workplace Safety and Insurance Board under the Occupational Health and Safety Act and the Workplace Safety and Insurance Act.
Hand-held Class 4 lasers are very rarely found in industry. In medical and veterinary practices, cosmetic treatment centres (skin care, hair and tattoo removal) and for some holistic uses, Class 4 devices are routinely hand-held. In Ontario, in addition to ANSI Standard Z136.1, CSA Standard Z386-14 – Safe Use of Lasers in Health Care Facilities is referred to for medical applications. This standard is based on the ANSI Z136.3 standard.
To assist employers, supervisors, and workers in the safe use of these devices, two guidelines are available which summarize the most important requirements in ANSI Standard Z136.1 and ANSI Standard Z136.3. Links to Health Canada’s safety guideline for owners and operators of laser hair removal facilities and British Columbia’s guideline for the safe use of lasers in veterinary practices can be found in the Other guidance materials section of this document. These guidelines may be used by employers in the development of workplace training and by LSOs when drafting written standard operating procedures.
Some of the other hazards which must be considered by the employer and relevant workplace parties such as the LSO where required, include:
During assembly, installation, setup, alignment, servicing, and maintenance, safety devices and features may need to be temporarily disabled. The standard operating procedures should identify these deficiencies and provide for alternative measures of protection.
The workplace employer has a duty to ensure the safety of all workers when an outside contractor is servicing the laser.
The employer must make sure workers know about hazards associated with working with lasers and control measures by providing information, instruction, and supervision on how to work safely. It's the law!
Follow the instructions provided by the employer, manufacturer’s operating manuals and, when appointed, the LSO. For Class 3B and Class 4 lasers, written Standard Operating Procedures must be available.
Know the name and contact information of the LSO for each laser you are using (for Class 3B and Class 4 equipment). He or she is the employer’s representative and on-site expert in laser safety matters.
Do not knowingly expose yourself and others to either the direct laser beam or its reflection.
Know the Class of Laser(s) you are working with and the nominal hazard zone (the space where exposure to the laser beam is hazardous), if applicable.
Wear and use the protective equipment required by the employer.
Report any hazards or injuries to your supervisor and the LSO.
CSA Z386-14 – Safe Use of Lasers in Health Care [based on ANSI Standard Z136.3 Safe Use of Lasers in Health Care]. Users include aestheticians, physicians, medical educators, dentists, veterinarians, dermatologists, and the public [lasers for home use].
International Electrochemical Commission (IEC) 60825 Series of Laser Standards
The IEC standards mirror the ANSI standards and would be of benefit to manufacturers that wish to sell their laser systems in Europe.
Health Canada's Therapeutic Products Directorate is responsible for imposing standards on lasers imported into Canada or manufactured here, including the correct classification of devices:
See their List of Recognized Standards for Medical Devices (PDF) which includes standards for medical lasers.
ISBN 978-1-4606-4615-1 (HTML)