What is a workplace hazard?
The essential feature of a hazard is its potential to cause harm , not whether harm has already occurred. It can reside in a material source, such as a moving part or a chemical agent; in a situation, such as working at heights; in an activity, such as handling loads; or in organizational and psychosocial conditions capable of affecting health. This includes physical, mental, or cognitive harm, not just visible accidents.
Naming the hazard specifically improves the analysis. “Machine” is too broad; “accessible cutting zone during unblocking” describes the source and the relevant situation. The hazard may still be present even if no one is exposed at any given time. The existence and magnitude of the associated risk change depending on who has access, for how long, how frequently, and under what controls.
Differences between hazard, risk, hazardous situation and harm
These concepts represent distinct parts of a preventive sequence:
- Danger: that which has the capacity to cause harm.
- Dangerous situation: circumstance in which a person is exposed to one or more dangers.
- Hazardous event: an event that can trigger harm, such as an unexpected start-up.
- Occupational risk: possibility of suffering harm and assessment of its severity according to probability and severity.
- Damage: injury, illness or pathology already materialized.
An accessible blade is a hazard; reaching in to clear a jam creates an exposure situation; unexpected start-up could be the event; cuts or amputations are possible injuries. The level of risk depends on frequency, access, energy, consequences, and the reliability of controls. Therefore, hazard and risk should not be used interchangeably in an assessment.
Types of workplace hazards
A classification serves as a reminder, but it must be adapted to the activity. Common groups include mechanical and safety hazards —falls, entrapment, vehicles, electricity, or fires; physical hazards , such as noise, vibration, radiation, or temperature; chemical hazards ; biological hazards ; ergonomic hazards , related to forces, postures, repetition, or design; and psychosocial and organizational hazards , such as excessive workloads, lack of autonomy, violence, schedules, or insufficient resources.
The groups can overlap. A maintenance task combines electrical energy, moving parts, products, postures, and time pressure. Furthermore, “chemical hazard” in CLP labeling has sector-specific rules on classes and categories that do not replace an assessment of actual use. Generic lists help to avoid overlooking certain families, but they do not demonstrate that all jobs, people, and circumstances at a specific site have been considered.
How are hazards identified?
Identification begins with understanding the actual work. The INSST suggests asking if there is a source of harm, who or what could be harmed, and how this could happen. Processes, locations, equipment, energy sources, substances, organization, manufacturer’s instructions, safety data sheets, measurements, previous assessments, and incident and harm history should all be reviewed. Observation and consultation with those performing the tasks reveal discrepancies between the procedure and the practice.
The scope includes normal operation, start-up and shutdown, cleaning, adjustment, maintenance, breakdowns, and foreseeable emergencies. It also covers occasional tasks, teleworking or off-site work, contractors, visitors, and particularly vulnerable individuals where applicable. New hazards are identified before introducing equipment, products, technology, or organizational changes. A closed list or a single visual inspection does not cover invisible exposures or psychosocial factors.
From hazard identification to risk assessment
Identifying the hazard alone does not determine its priority. Next, the potential harm, the people exposed, the route and duration of exposure, existing controls, and the conditions that could cause them to fail are described. Using an appropriate method, the risk is estimated or measured and compared with legal requirements, reference values, and technical criteria. If there is significant doubt, the Regulations for Prevention Services guide the adoption of the approach most favorable to prevention.
The assessment should lead to a decision: eliminate, reduce, maintain controls, or study in greater detail. A serious hazard can generate different risks at two different locations due to distance, exposure time, or a reliable barrier. Conversely, a harm initially considered minor can become a priority if the exposure is continuous or affects many people. A matrix score should never replace technical judgment or regulatory compliance.
How to eliminate or control a hazard
The first question is whether the hazardous source or situation can be eliminated: by removing an operation, designing the process without access to hazardous energy, or avoiding the use of a substance. If this is not feasible, a less hazardous alternative is used, and the source is addressed through enclosures, extraction, safe automation, isolation, or separation. Work organization, procedures, training, and personal protective equipment complement the technical and collective controls.
Law 31/1995 requires prioritizing collective protection over individual protection and taking into account technological advancements. Controlling risk does not always eliminate danger: a guarded machine retains energy capable of causing harm if opened during maintenance. Therefore, residual risk is managed, barriers are maintained, their limits are communicated, and reassessments are carried out after changes, incidents, or signs of inadequacy.
Applicable technical and legal framework
Article 4 of Law 31/1995 does not include a general, independent definition of “hazard.” It does, however, define occupational risk , harm, working conditions, and potentially hazardous processes, activities, equipment, or products; the latter give rise to risks in the absence of specific measures. Article 15 mandates the prevention of risks, their mitigation at source, and the replacement of hazardous elements. Royal Decree 39/1997 requires obtaining information to determine measures regarding risks that have not been prevented.
For the general technical concept, official sources converge on the potential capacity to cause harm. The INSST structures the identification around the source, the affected person, and the form of the harm; OiRA requires examining what can cause injury; the ILO and ISO employ equivalent formulations in their OSH frameworks. Sector-specific standards may define specific hazards—chemical, biological, machine-related, or others—so the regulations applicable to the activity should always be checked.
