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Guidance on Hazards and carrying out risk assessments

Carrying out a risk assessment can be made simpler by following a number of steps.

  1. Identify (and list) the hazards or hazardous processes. 
  2. Decide who might be harmed and how.
  3. Evaluate the risk, considering any existing precautions or control measures.
  4. Identify what actions should be taken (by who and when) to eliminate or reduce the risk to an acceptable level.
  5. Record the assessment (use the recommended forms – see below).
  6. Review and revise if circumstances change.

Taking each step in more detail:

1. Identify the hazards

The following table lists the sorts of harm which can result from exposure to lasers.


Optical Laser hazards can be quantified to some extent by using maximum permissible exposure (MPE, see later section).but laser accident statistics show that the majority of accidents are caused by other hazards such as tripping, electrocution. The following is a list of more conventional hazards that may be associated with laser equipment:

• Electrical hazards, especially from high voltage power supplies (all portable electrical equipment must be PAT tested)

• Trip hazards from trailing cables and water pipes

• Leaks from water cooling

• Mechanical hazards from moving parts such as motorised translation stages, pumps, motors etc

• Other sources of intense light from, for example, flashlamps

• Toxic chemicals

• Explosion or implosion from evacuated tubes or pressurised systems

• Fire from beam contact with combustible materials

• Hazards from coolants such as liquid nitrogen

• Formation of ozone

• Risk of asphyxiation from leaking cylinders in confined areas

For laser activities a useful way to identify all the hazards is to compartmentalise the process.

  • The laser - look for all the hazards starting from the laser beam output aperture BACK to the wall socket. This could include electrical hazards from the power supply, trip hazards from the cables, beam hazards if covers are removed etc.
  • The beam delivery - look for all the beam related hazards from the laser beam output aperture to the beam stop. Consider specular and diffuse reflections and the possibility of inadvertent access to the beam.
  • The laser process - look for all the hazards associated with the process. Are toxic chemicals or dangerous fumes released? Can the target accidentally move?
  • Environment and people – look for hazards associated with the environment or the people. Could the environment affect the safety of the laser activity, e.g. extremes of temperature, humidity etc? Could the laser activity affect the environment? Can people affect the safety? For instance an experienced researcher may put other people at risk, or alternatively can an inexperienced, or unauthorised person get access to the equipment?

2. Decide who might be harmed and how.

The people who might be harmed include the users but other people as well such as cleaners, maintenance staff, visitors, contractors and the public must be considered. Considering how they might be harmed must include normal operations but also situations when something has gone wrong.

3. Evaluate the risk.

Take each identified hazard and, taking into account existing controls, evaluate the risk associated with that hazard. Risk can simply be classified as high, medium or low.

4. Identify the actions to be taken.

A set of actions must be produced which will remove the hazards completely or reduce the risks to an acceptable level. High risks should take priority, followed by medium and low. Someone responsible for carrying out the actions and a date for completion must be identified.

5. Record the assessment.

The risk assessments must be written up as evidence of the fact it has been done (for audits) but more importantly as a means of reference for anyone working with or associated with the laser or laser application. The recommended method of recording the assessment is by using the pro-forma.

6. Review and revise.

The risk assessment needs to be reviewed on a regular basis, at least annually. It should also be revised whenever there is a significant change in the activity.