Laser Sources of Artificial Optical Radiation (AOR) - Class 3B and 4 Lasers (PC-15) Policy and Code of Practice


Introduction and Scope

The College recognises the health risks of using laser sources of coherent Artificial Optical Radiation (AOR) and that misuse can cause serious injury.    

This Code of Practice describes the general arrangements for the safe use of coherent AOR sources in the form of Class 3B and 4 lasers within the College.  Class 1 and 2 lasers are considered to be safe for use providing no direct beam viewing or magnification is involved – the use these lasers are addressed within Workplace Safety Guidance (PC-08).

Policy and management arrangements relating to non-coherent AOR sources are described separately.        

This Code of Practice is supported by Faculty and/or Departmental procedures, which describe local arrangements for the implementation of this policy.          

Statement of College Policy

All work involving the use of Lasers, carried out under the control of the College will be carried out in such a way as to prevent undue risk to those carrying out the work and those who may be otherwise affected by the work.        

The College will ensure compliance with the statutory requirements contained within the Control of Artificial Optical Radiation at Work Regulations 2010 and that best practice in the safe use of laser products is followed.  (BS60825-14: 2004)       

No Class 3B and 4 laser may be operated within the College without first being registered and the risks associated with is use being assessed and documented by a competent person. Lasers will only be operated by registered, trained and competent personnel.  Wherever possible, Class 3B and 4 lasers will be operated within engineered enclosures which physically exclude personnel during their use. Where this is not practicable, appropriate procedural controls and personal protective equipment will be employed to ensure the safety of personnel.        

Within the College, this policy is implemented by way of a laser safety management system, which includes both College and Faculty codes of practice. These management systems provide practical information on how to ensure that laser safety risks are properly assessed, that suitable action is taken to reduce risks and implement safe systems of work, and that adequate safety information is provided to all laser users.  

Roles and Responsibilities

Heads of Departments/Divisions

Heads of Departments/Divisions are responsible for their Department’s compliance with statutory and College requirements and will ensure that:

  • No Class 3B or Class 4 lasers are used in undesignated areas, or for any College activity without their prior registration or by unregistered workers.
  • Class 3B and 4 lasers are enclosed wherever possible.
  • In all circumstances the lowest class of laser is used.
  • Risk assessments and protocols are approved prior to the commencement of work with Class 3B or 4 lasers. 
  • Safe systems of work are in place and implemented.
  • Staff with supervisory and safety responsibilities (incl. DLSO) are suitably trained and appointed.

College Laser Safety Adviser (CLSA)

The CLSA provides expert advice relating to the safe use of lasers within the College. The LSA is appointed with the following duties:

  • To provide or arrange for the provision of expert advice.
  • To assist in the development and maintenance of College-wide laser safety management systems.   
  • Maintaining central registers of designated areas, registered workers and equipment, based on information provided by departments/divisions.
  • Providing specialist input to investigating the causes, consequences and corrective actions following laser accidents and incidents.
  • Provide advice on the suitability of training for personnel engaged in work with lasers.

Departmental Laser Safety Officer (DLSO)

The DLSO is appointed by the Head of Department and is responsible for ensuring that lasers are identified and used in accordance with College laser safety policy within their area of responsibility.  The DLSO has the following duties:

  • Ensuring work carried out with lasers is compliant with College policy
  • Identification of all class 3B and 4 lasers in use within the Department
  • The correct labeling of lasers and identification of designated areas
  • Administering the Departmental equipment and personnel registration process
  • Assisting users in drawing up protocols/systems of work for lasers that are not fully enclosed.
  • Approving laser safety risk assessments
  • Providing local training for laser users
  • Providing advice on the selection of Personal Protective Equipment  

Registered Laser Users

All staff and students must be registered with the DLSO before commencing work with Class 3B and Class 4 lasers - these personnel are "Registered Users". Registered Users are required to comply with College requirements and standards and approved protocols and take responsibility for:

  • Maintaining their competence for the use they make of Class 3B or Class 4 lasers by attending College Laser User training or demonstrating satisfactory competence to the DLSO.
  • Their registration and the registration of Class 3B or Class 4 lasers in their use.
  • Not putting others at risk by their work
  • Supervising others working on or near Class 3B or Class 4 lasers under their control
  • Informing their supervisor, DLSO or Department Safety Officer if they see a problem that is outside their area of competency to deal with

Health Protection

Biological Effects

The eyes are the part of the body most susceptible to injury from laser radiation. The amount of energy absorbed by the body depends on factors such as the wavelength of the radiation, power of the laser beam and duration of exposure. Wavelengths in the UV region are primarily absorbed by the cornea, resulting in photo-keratitis (or snow blindness) where exposure is excessive. Exposure to visible laser radiation can cause thermal injuries to the retina and overexposure to infra red (IR) laser radiation can result in corneal burns and cataracts. There is also a risk of skin damage such as skin burns from higher power lasers. In addition to the hazards from laser radiation, laser equipment may also give rise to many other associated hazards such as fire, toxic fumes, electric shock etc. Medical advice should be sought in the event of laser eye or skin damage.

Eye Health

There is no statutory requirement for medical surveillance of laser workers. However, if a user has concerns regarding their eye health, perhaps because of existing conditions (e.g. cataracts, macular degeneration, hyper-sensitivity to light, pterygium, retinitis pigmentosa) or a previous laser-related eye injury, they should take advice from their GP and, if still concerned, notify their supervisor who can then refer their details to Occupational Health for review.

Implementation Arrangements

Departmental/Divisional Arrangements

Departments/Divisions should ensure that local laser safety management systems are in place to allow work to carried out safely. The DLSO is responsible for the maintenance of local management systems and will ensure compliance with the system through periodic inspections, the findings of which will be reported to the Head of Department, Faculty Safety Officer and CLSA.

Prior to the commencement of work, Laser Users will ensure that Laser equipment is registered, that the proposed usage has been suitably risk assessed and that a Scheme of Work has been written which adequately describes the relevant control measures.  All proposed work will be reviewed by the DLSO prior to commencement.                        

User Registration, Training and Competency

All Class 3B and Class 4 laser users must be registered and must, as a minimum, complete College "Introduction to Laser Safety" training. Users   must be trained in the to use the laser, laser area procedures and emergency procedures. In addition they must know how control systems work, their limits and actions to be taken in the event of failure.  Users may also require specific training for instance in handling gases and cryogens, conducting risk assessments (RAFT), etc.  Departmental arrangements for the registration of users will be managed by the DLSO, who together with the user’s supervisor or PI will approve user application.

The College requires that all personnel working with Class 3B and 4 lasers are registered and assigned a competency level* by their academic supervisor. Three levels of user competency are defined as follows:

Level 1: Basic understandingLevel 2:  Supervised userLevel 3: Competent user
All persons working in areas where lasers from Class 3B or 4 are being used (but not using lasers). All persons using lasers from Class 3B or 4. All persons adjusting, aligning or setting up lasers from Class 3B or 4.
Completion of  Introduction to Laser Safety and successful completion of end of course Multiple Choice Question Test. Basic Understanding level plus authorisation by Principal Investigator and endorsement by DLSO. Supervised level plus authorisation by Principal Investigator and endorsement by DLSO.
Summary of the table's contents

As an individual gains more experience, the competency level may change. In this case the supervisor needs to inform the DLSO, so that the relevant competency level can be updated.

Registration of Lasers

Lasers will be registered electronically in accordance with the Departmental procedures. A central register of lasers will be maintained within each Department by the DLSO.  All lasers, except Class 1, class 2, approved laser pointers or embedded lasers in products such as DVD players and laser printers need to be registered.

Should a laser be modified or moved to a different location, the DLSO must be informed to ensure that the revised arrangements for laser use are suitably controlled and risk assessed.

College Manufactured Lasers

Extreme caution should be exercised by researchers who are engaged in the construction of equipment that may give rise to the emission of laser light.  As the potential for injury in such circumstances may be significant, the matter should be discussed with the DLSO and an assessment of risk must form part of the work protocol. The individual who manufactures the laser must ensure that the appropriate technical standards are met and that the laser is assigned and labeled with the appropriate hazard class following a suitable measurement of power.  

It is the responsibility of the PI to ensure any laser manufactured in their Department is notified to the DLSO before it is commissioned, so that it may be inspected prior to Departmental registration.

Classification of Lasers

It is the responsibility of the laser manufacturer to provide the correct classification of a laser product. This classification is made on the basis of a combination of output power(s) and wavelength(s) of the accessible laser radiation over the full range of capability during operation at any time after manufacture, which results in its allocation to the highest appropriate class.

Maximum Permissible Exposure Levels (MPE)

Maximum Permissible Exposure limits are those levels of laser radiation to which, in normal circumstances, persons may be exposed without suffering adverse effects. A guide to MPE levels are given in BS EN 60825-1:2014. MPEs are based upon biological data collected to date.

Accessible Emission Limit (AEL)

The AEL is the maximum value of accessible laser radiation to which an individual could be exposed during the operation of a laser and is dependent on the laser class, defined in the next section. The AEL depends on the power or energy and wavelength of the laser beam, as well as the size and duration (continuous or pulsed) of the beam. This is generally expressed in Watts or Joules.

Laser Hazard Classes

Lasers are grouped according to ability to do harm, the higher the number the greater the harm. The current laser classes are: 1, 1M, 2, 2M, 3R, 3B and 4

Class1 lasers


 Class 1 (AEL<0.3mW)

Class 1 lasers are products where the irradiance (measured in watts per metre square) of the accessible laser beam (the accessible emission) does not exceed the Maximum Permissible Exposure (MPE) value. Therefore, for Class 1 laser products the output power is below the level at which it is believed eye damage will occur. Exposure to the beam of a Class 1 laser will not result in eye injury and may therefore be considered safe. However, some Class 1 laser products may contain laser systems of a higher class but there are adequate engineering control measures to ensure that access to the beam is not reasonably likely. Examples of such products include laser printers and compact disc players. Anyone who dismantles a Class 1 laser product that contains a higher class laser system is potentially at risk of exposure to a hazardous laser beam. A laser that is inherently safe and cannot exceed the MPE under any circumstances is exempt from the classification system.

Note that a Class 1 laser product may contain a Class 4 laser system, but be safe by engineering design. The control measures may include restricting access to the laser beam by enclosures and interlocked panels. In some applications, the beam may only present a risk of injury over small distances. It is sometimes necessary to restrict access to the area where the beam is cutting or welding material so as to avoid exposure to moving parts and material ejected from the work site.


Class 1M (AEL<0.3mW)Class 1M

Class 1M lasers are products which produce either a highly divergent beam or a large diameter beam. Therefore, only a small part of the whole laser beam can enter the eye. However, these laser products can be harmful to the eye if the beam is viewed using magnifying optical instruments. Some of the lasers used for fibre-optic communication systems are Class 1M laser products.


Class 2  (AEL<1mW)

Class 2 lasers are limited to a maximum output power of 1 mW and the beam must have a wavelength between 400 and 700 nm. A person receiving an eye exposure from a Class 2 laser beam, either accidentally or as a result of someone else's deliberate action (misuse) will be protected from injury by their own natural aversion response. This is a natural involuntary response that causes the individual to blink and avert their head thereby terminating the eye exposure. Repeated, deliberate exposure to the laser beam may not be safe. Some laser pointers and barcode scanners are Class 2 laser products.Class 2M

Class 2M (AEL<1mW)

Class 2M lasers are products which produce either a highly divergent beam or a large diameter beam within the wavelength range 400 to 700 nm. Therefore, only a small part of the whole laser beam can enter the eye and this is limited to 1 mW, similar to a Class 2 laser product. However, these products can be harmful to the eye if the beam is viewed using magnifying optical instruments or for long periods of time.

Class 3R (AEL<5mW)Class 3R

Class 3R lasers are higher powered devices than Class 1 and Class 2 and may have a maximum output power of 5 mW or five times the Accessible Emission Limit (AEL) for a Class 1 product. The laser beams from these products exceed the maximum permissible exposure for accidental viewing and can potentially cause eye injuries, but the actual risk of injury following a short, accidental exposure, is still small.

Class 3B

Class 3B (AEL<0.5W)

Class 3B lasers may have an output power of up to 500 mW. Class 3B lasers may have sufficient power to cause an eye injury, both from the direct beam and from reflections. The higher the output power of the device the greater the risk of injury. Class 3B lasers are therefore considered hazardous to the eye. However, the extent and severity of any eye injury arising from an exposure to the laser beam of a Class 3B laser will depend upon several factors including the radiant power entering the eye and the duration of the exposure. Examples of Class 3B products include lasers used for physiotherapy treatments and many research lasers.

Class 4 (AEL>0.5W)Class 4 Lasers

Class 4 lasers have an output power greater than 500 mW. There is no upper restriction on output power. Class 4 lasers are capable of causing injury to both the eye and skin and will also present a fire hazard if sufficiently high output powers are used. Lasers used for many laser displays, laser surgery and cutting metals may be Class 4 products. Many Class 4 laser products are safe during normal use, but may not have all of the protection measures required for a Class 1 product. An example would be an enclosure with an open roof; it is possible that someone could get a ladder and climb over the enclosure to get access to the laser beam.