Investigating workplace accidents is not just an administrative procedure or a formal reaction to damage already done. It’s an essential tool to understand what happened, why it happened, and whether it could have been avoided. The quality of the investigation has significant consequences, including the adoption of corrective measures, the imposition of sanctions, and the recognition of employer responsibilities.
Workplace Accident Investigations
A deficient investigation can harm all parties involved. It can leave a worker without protection if the accident was caused by a preventable failure. On the other hand, it can also lead to sanctions or employer responsibilities when the accident is caused by factors other than those initially apparent.
Investigating Workplace Accidents as a Legal Obligation
The starting point is the Ley 31/1995, de Prevención de Riesgos Laborales (Law 31/1995 on Prevention of Occupational Risks), which recognizes the right of workers to effective protection in terms of safety and health at work and imposes a duty of protection on employers. This duty is not limited to providing equipment, training, or conducting an initial risk assessment; it requires continuous preventive action, adapted to the reality of the work and the evolution of risks.
Specifically, article 16.3 of the Law on Prevention of Occupational Risks states that when damage to workers’ health has occurred or there are indications of insufficient preventive measures, the employer must conduct an investigation to detect the causes of the facts. This provision is essential, as the law does not order an investigation solely to describe the accident but to discover its causes.
The difference is important. A description may be limited to stating that a worker fell, was trapped, suffered a overturn, received an impact, or suffered an intoxication. A causal investigation must go further: it must analyze the work environment, the equipment used, the procedure followed, the training received, the organization of the task, the worker’s physical condition, the existence of external factors, the adequacy of preventive measures, and the causal relationship between all these elements.
In addition, failure to comply with this obligation can have sanctioning consequences. The Ley sobre Infracciones y Sanciones en el Orden Social (Law on Offenses and Penalties in the Social Order) classifies not conducting an investigation when damage to workers’ health occurs or there are indications of insufficient prevention as a serious offense.
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Determining Accident Causes
Investigating is not about presuming; it’s about determining the real cause. In the case of workplace accidents, there is a frequent risk of confusing the existence of an omitted preventive measure with the effective cause of the accident.
A good investigation can be decisive in protecting the rights of the worker who had the accident or their beneficiaries. It can allow for proof that the risk assessment was incomplete, the work procedure was inadequate, or the equipment was not suitable or was in poor condition.
From this perspective, investigating well favors the worker because it avoids attributing the accident to “imprudence” or “human error” without analyzing whether that error was induced, permitted, or not avoided by a deficient preventive organization.
Investigating can also favor the employer. Not every workplace accident necessarily implies an employer infringement. The employer’s obligation in terms of prevention is intense, but it does not automatically make the employer responsible for any damage that occurs during the provision of services.
A complete investigation can demonstrate, depending on the case, that the required preventive measures existed and were adequate, the worker had received sufficient training and information, or the accident occurred due to an external, unforeseeable, or non-imputable cause.
This does not mean minimizing employer obligations but rather avoiding an unjust conclusion. The purpose of the investigation should not be to confirm a preconceived hypothesis but to contrast all possible hypotheses.
Multidisciplinary Accident Analysis
The investigation of workplace accidents cannot be solely legal. The law determines obligations, responsibilities, and consequences, but it often does not suffice to explain how an accident physically occurred.
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Accidents occur in technical, human, medical, organizational, and material contexts. Therefore, a rigorous investigation may require the intervention of other disciplines, including engineering and technical disciplines, occupational medicine and forensic medicine, and ergonomics, psychosociology, and work organization.
For instance, in accidents involving machinery, vehicles, structures, electrical installations, lifting equipment, explosive atmospheres, work at heights, entrapments, or overturns, engineering can be indispensable. An analysis can determine if the machine was suitable for the task, if the slope, load, speed, or trajectory were compatible with safe use, or if the equipment required specific devices.
Similarly, the medical dimension is equally essential. Not all accidents have an exclusively external cause. There can be syncopes, strokes, heart attacks, epileptic crises, metabolic disorders, alcohol or drug consumption, medication effects, extreme fatigue, or pre-existing pathologies that influence the production of the accident.
This does not automatically exclude employer responsibility but obliges analyzing causality with rigor. For example, if a worker loses control of a machine, falls from a height, or suffers a fatal accident, it can be decisive to know if they suffered a disabling medical episode before the impact.
Ergonomic and Psychosocial Factors
The investigation can also involve ergonomics and psychosociology to evaluate the normalization of unsafe behaviors or excessive confidence generated by poorly controlled routines.
Given the probative force that inspection actions can have, it’s key that the factual finding is precise, complete, and technically sound. The Ley 23/2015, Ordenadora del Sistema de Inspección de Trabajo y Seguridad Social (Law 23/2015, Ordering the Labor and Social Security Inspection System), recognizes the presumption of certainty of the facts found by the Labor and Social Security Inspection, formalized in acts and reports, without prejudice to the evidence that the interested parties may provide.
