How to investigate an accident or incident

Each year around 600 accidents or incidents lead to prosecution by the HSE, with about 100 more being prosecuted by local authorities. Personal injury claims are over double this number.

Some lead contractors operate a “3 strikes and you’re out” policy on their subcontractors regarding health & safety issues, so preventing future accidents could be vital to your business, not to mention the moral and legal issues.

Investigating the accident

The HSE describes the investigation of accidents and incidents as “an essential part” of managing health and safety. Their guidance HSG245, Investigating Accidents and Incidents, says “learning the lessons from what you discover is at the heart of preventing accidents and incidents” and “carrying out your own health and safety investigations will provide you with a deeper understanding of the risks associated with your work activities”.

You need to take a structured and methodical approach to gathering and analysing the information gathered in your investigation to establish the immediate causes, but also the underlying causes of the accident. You need to understand why the accident happened, otherwise you can’t prevent it happening again. How the company investigates the accident reflects on how the management see health & safety.

Your report

Your report should be the last stage in your company’s response to an accident, but also the first stage in an improvement process.  Don’t go down the “blaming an individual” route, as, as the HSE says this is “ultimately fruitless”. Look at the circumstances that led to the individual making the decisions they did which led to the accident. Blaming an individual, disciplining them and getting rid of them will only send a negative message to the rest of the workforce.  They won’t want to report something if they are worried about the consequences.

Look on the accident as a chance to improve your systems of work, to keep people safe in the future. Review your risk assessments after carrying out the investigation into the accident or near miss and if necessary revise them. If, after carrying out your investigation you conclude that there was nothing wrong with your systems, just a pure operator error or short cut then that is what your report should say.

Sometimes there is an assumption that there need to be changes with the risk assessment or controls, but although this is often the case, it is not always correct. Try not to react with a knee-jerk reaction.  The risk assessment or controls may be correct, so you may need to look at training, or the general culture.

Gather evidence

First of all, make sure that no-one touches the scene of the accident, they may just be trying to tidy up, but they could be altering the cause of the accident.

You might think you know what happened, but you need to gather all the facts.  Don’t just look for evidence to support your suspicions. An investigation should take place as soon as possible, interviewing witnesses and keeping good records of the evidence sought and make sure you date everything.  Any notes taken in the immediate aftermath of the accident should be transferred to a new document and signed and dated.  Before carrying out interviews decide on the structure of the interview and the questions to be asked.  Take photos of anything that will help the investigation and back them up as soon as possible.

Analyse why the accident happened

Instead of just looking at the circumstances of the accident, why not look at how the task should have been carried and work out how to make that more likely in the future.

Compare your safe system of work with what is actually taking place, there can be quite a big gap!  Look at how people who have not had any accidents are working. Compare their methods to the method of the worker involved in the accident.  Watch people working, ask them to work as if you weren’t there.  You may find that people have different ways of performing the same task, some more safely than others.

The next step is to find out why employees are not following the safe system of work, is it time pressure? Are they only completing a few stages of a complicated process because they are rushed, or are some stages unnecessary?  The people performing the task are the experts, so find out from them the best way to perform the task and align your safe system of work with that.

In house or an external investigation?

Consider whether to appoint a member of the existing team to investigate an accident, or whether to appoint an external adviser, or someone from a different site within the same organisation.  You are more likely to get a full report from an external investigator as they won’t be considering the effects it may have on their job.  On the other hand an in-house investigator will have in-depth knowledge of the safety systems.

Do you know what an “accident” is?

Many companies have some kind of transport, such as vans or forklift trucks, but these will not always be seen as an area of concern. Do you investigate all the bumps and scrapes on your forklift?  These were still accidents, and should be investigated, someone could have been injured.

What is an accident or near miss may be spelled out in a written policy, but your employees also need to know, not just what is reportable under RIDDOR.

Consider ‘legal privilege’

An accident investigation report, or an expert opinion commissioned as part of an investigation, can sometimes claim to be “legally privileged”  if it fulfils key conditions: a lawyer has instructed the business to carry it out to obtain legal advice; the report has legal advice as its dominant purpose; and the lawyer could “reasonably contemplate” litigation at the time it was commissioned.

If legal privilege applies, the HSE or local authority cannot compel the organisation to disclose the documents under Section 20(2)(k) of the Health and Safety at Work Act. Meanwhile, a lawyer can give a client guidance on their position.

If a report is compiled claiming “legal privilege” then it must be kept confidential.


As long as you are not claiming legal privilege then share the results of your investigation.  If you share with board members it helps to ensure that they are aware that there are health and safety problems.  This can assist with securing a budget for improvements in equipment or training.  If you share the results with employees it demonstrates to them that you are taking the accident or incident seriously. This encourages them to report future incidents or near misses.

If the HSE investigate the accident they will look at whether you were aware of the problem, because of a previous accident, and your response at the time to the incident. A failure to investigate incidents and act on the findings is relevant for determining culpability if your company is prosecuted.

HSE publication HSG245 Investigating accidents and incidents can be found here.


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