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Although the number of workplace accidents has been decreasing since the 1950s, analysing them remains crucial to ensuring effective risk prevention in companies. The aim is to prevent the accident from happening again, by identifying any failures in the equipment used or malfunctions in the organisation of work.
When and how should a workplace accident analysis be carried out? Following which methodology? Tennaxia takes you through all of this in detail in this article.
Analysing a workplace accident: what's at stake?
As a reminder, a workplace accident is defined as “whatever the cause, an accident occurring as a result of, or in connection with, work, to any employee or person working, in any capacity or in any place whatsoever, for one or more employers or business owners” (Article L411-1 of the Social Security Code).
Several elements emerge from this definition:
- the accident must result from an event that caused physical or mental harm to a worker;
- the accident must occur in the course of carrying out work, but not necessarily on the company's premises;
- the existence of a subordinate relationship (employment relationship) between the injured worker and their employer.
The regulations also specify that an accident occurring during the journey to and from work should also be considered a workplace accident, between:
- the worker's main residence and the workplace (or any other place they regularly travel to for family reasons);
- the workplace and the place where the worker eats
The number of workplace accidents, although falling in recent years, remains very high. According to Assurance Maladie's figures, 717,719 workplace accidents were recognised in 2023, of which 759 were fatal.
Analysing workplace accidents plays a crucial role in reducing their frequency. Indeed, it aims to identify the causes of the accident so that corrective and preventive actions can be put in place, thereby preventing the accident from recurring.
For companies, this analysis carries both an economic dimension (reducing the direct and indirect costs linked to workplace accidents) and a legal one, since the employer's civil and/or criminal liability may be engaged in the event of inexcusable misconduct.
But workplace accidents also generate indirect costs which can be very high (loss of productivity, possible training and recruitment costs linked to replacing the injured employee, replacement of faulty equipment where applicable, etc.).
How to analyse a workplace accident?
In practice, two main types of workplace accident analysis can be distinguished:
- quantitative analysis: this covers a large number of accidents and, using statistical indicators (frequency rate, frequency index, severity rate), aims to provide an overall view of accident risks within the company and to establish key action priorities. This analysis is nonetheless insufficient to define a risk prevention policy within the company.
- qualitative analysis: this is the most relevant approach for addressing the direct and indirect causes of a workplace accident and defining the most suitable corrective and preventive actions. It aims to understand why the accident occurred, by examining all the components of the system (technical, organisational, human) and their interactions.
In practice, the qualitative analysis of a workplace accident involves 7 key steps, which we set out below.
1) Inform the employer
An employee who is the victim of a workplace accident must inform their employer within 24 hours at the latest, in accordance with the procedure previously set out within the company. This deadline naturally does not apply in cases of force majeure, absolute impossibility, or a legitimate reason.
Following this notification, the employer then completes a workplace accident declaration (DAT) and must take the necessary immediate prevention measures to avoid a further accident (for example: prohibiting access to a work area or the use of a piece of equipment).
Key information relating to the workplace accident must be kept in a specific register, which must include (at a minimum):
- the date of the accident;
- the person(s) involved;
- the location where the accident occurred;
- the circumstances;
- the consequences for the victim.
2) Set up a workplace accident analysis group
As soon as possible, an analysis group with the necessary skills must be set up. It will be responsible for gathering information about the workplace accident, identifying its causes, and proposing actions to prevent it from happening again. The composition and size of the group must be tailored both to the size of the company and to the nature of the accident and the extent of the harm caused.
3) Gather information about the accident and identify the facts
Once formed, the analysis group must gather all information relating to the workplace accident as quickly as possible. The INRS notes in this regard that the circumstances of the accident can be analysed under 5 themes:
- the organisation of work;
- the profile of the victim;
- the activity being carried out when the accident occurred;
- the work environment (location, lighting, noise, etc.);
- the products and equipment used at the time of the accident (machinery, tools, chemical products, etc.).
4) Determine the causes of the accident
The working group must reconstruct the sequence of events leading to the workplace accident and consider:
- its direct causes (events that directly caused the accident);
- its indirect causes (upstream causes that contributed to it occurring).
This is the most important step in the analysis, as it determines the effectiveness of the prevention measures that will subsequently be taken. Various methods are commonly used to carry this out, such as the fault tree method (we will come back to this) or the “5 Ms” method (Manpower, Milieu, Material, Method and Machine).
5) Choose corrective actions and draw up an action plan
Based on the various causes identified in the previous step, the analysis group must define the corrective actions considered most suitable to prevent a similar accident from occurring. These various actions must be listed as part of an action plan specifying, for each of them (at a minimum):
- their implementation timeframe;
- the estimated implementation cost;
- the person responsible for implementing it.
6) Carry out a debrief
Once the action plan has been drawn up, it is very important to carry out a debrief with the victim as well as with their colleagues. The aim is to encourage acceptance of the various actions defined, but also to raise teams' awareness so they remain more vigilant in carrying out their activities.
7) Update the single occupational risk assessment document (DUERP)
Analysing a workplace accident must necessarily lead to an update of the DUERP (and the PAPRIPACT, in companies with fewer than 50 employees).
Two scenarios can be distinguished:
- the accident risk had not yet been identified in the single document, in which case it must be included in the risk assessment for the work unit concerned.
- the risk had already been identified: in this case, it is necessary to consider why the accident still occurred despite the measures already in place, and to update those measures accordingly.
Focus on the fault tree method
The fault tree method is the preferred method for the qualitative analysis of a workplace accident. It was developed by the INRS and aims to go further than simply noting the accident, by seeking out its root causes.
In practice, this involves representing and organising, in a logical order, the events that led to or contributed to the accident, trying to trace back to the most distant causes possible. The fault tree is therefore built from right to left, or from top to bottom, starting from the harm caused.
This method involves two essential steps: building the fault tree and using it for prevention purposes.
Building the fault tree
The fault tree is built using two main sources of information: observations of the work environment and interviews carried out with the people involved (victim, witnesses, etc.). To ensure they are comprehensive, this information must be collected as quickly as possible after the accident.
Building the tree involves graphically representing the logical sequence of events identified as having led to or contributed to the harm.
Example of a fault tree in the construction sector (source: INRS):
Using the fault tree for prevention
Once the fault tree has been drawn up, the group in charge of the analysis must consider prevention measures for each event identified as an underlying cause of the workplace accident. The aim is to eliminate the possibility of such an event happening again.
The choice of measures to put in place is the employer's responsibility. In particular, it must be based on various criteria: their compliance with current health and safety regulations, their durability over time, the absence of new risks being created, and so on.
According to the INRS, there are four main success factors for analysing workplace accidents using the fault tree method:
1) the employer's commitment not to use the method as a way of assigning blame;
2) training for the people responsible for conducting the analysis (this could be, for example, an occupational health and safety officer and a member of the CSE);
3) informing staff, and managers in particular, about the aims of the method, in order to encourage their buy-in and participation;
4) once the various prevention measures have been put in place, communicating on the concrete improvements observed.
To find out more about this methodology, feel free to consult the brochure produced by the INRS.