IOSH Working Safely key terms

Any source, situation or act with the potential to cause harm, injury, ill health or damage. A hazard exists even when nobody is currently exposed to it.

The combination of how likely a hazard is to cause harm and how serious that harm would be. Risk is judged after considering who is exposed and for how long.

Physical injury, ill health, psychological damage or property and environmental damage caused by an incident. Harm is the outcome that safety measures are trying to prevent.

The arrangements, practices and legal duties that protect people from being harmed by work activity. It covers employees, contractors, visitors and anyone else affected by the work.

The legal obligations on an organisation to protect people from harm, so far as is reasonably practicable. They include providing safe systems, information, training, supervision and a written safety policy.

The duties placed on employees and others at work to take reasonable care of themselves and others, follow safety instructions and report hazards. Failing to do so can be a breach of law and of the employment contract.

A legal test balancing the risk against the time, trouble and cost of controlling it. Cost alone rarely justifies doing nothing where the risk is serious.

An unplanned event that has already caused injury, ill health or damage. Investigating accidents helps identify weaknesses in controls before something worse happens.

An unplanned event that did not cause harm only because of chance or good timing. Reporting near misses gives early warning of failing controls and is a sign of a healthy safety culture.

The shared attitudes, beliefs and behaviours that determine how seriously an organisation treats safety in practice. It shows in what people actually do when nobody is watching.

A structured process of identifying hazards, deciding who might be harmed and how, evaluating the risk and recording suitable controls. It should be reviewed when work, people or equipment change.

The preferred order of risk controls, starting with eliminating the hazard, then substituting, engineering controls, administrative controls and finally personal protective equipment. Higher options are more reliable because they depend less on human behaviour.

Removing a hazard completely, for example by stopping a task or redesigning a process so the danger no longer exists. It is the most effective control because nothing is left to fail.

Replacing a dangerous substance, machine or method with something less hazardous, such as a water-based cleaner instead of a solvent. It reduces risk at source but the replacement must itself be checked for new hazards.

A physical change to plant, equipment or the workplace that reduces exposure, such as guarding, extraction ventilation or machine interlocks. These controls work without relying on people remembering to use them.

Clothing or equipment worn by an individual to reduce exposure, such as gloves, goggles, hearing protection or safety footwear. It is a last resort because it protects only the wearer and fails if it is damaged or not worn properly.

A simple grid that combines likelihood and severity ratings to give a risk rating of high, medium or low. It helps people compare different risks and decide which need action first.

The risk that remains after controls have been applied. It must still be acceptable, and it should be recorded so people understand what protection they are relying on.

A quick mental check of changing conditions carried out while work is in progress, for example before entering a site or starting a task. It complements, but does not replace, a formal written assessment.

Loss of footing caused by wet or contaminated floors, trailing cables, uneven surfaces, poor lighting or obstructed walkways. These are among the most common causes of workplace injury and are largely preventable through good housekeeping.

Any work where a person could fall and be injured, including work above ground and work near openings or fragile surfaces. Falls from height are a leading cause of fatal injury and need collective protection such as guardrails or platforms before harnesses are considered.

Equipment and systems that stop a fall once it has started, such as a harness connected to a lanyard and anchor point. It limits injury but does not prevent the fall, so rescue arrangements must be planned in advance.

Correct selection, positioning and use of ladders so they stay stable and are used only for short, light tasks. The ladder should be on firm level ground, secured, and used with three points of contact where appropriate.

Moving or supporting a load by hand or bodily force, including lifting, lowering, pushing, pulling and carrying. Poor technique and repetitive or heavy loads cause musculoskeletal injuries, so assessment and mechanical aids are preferred.

Injury or pain affecting muscles, joints, tendons, ligaments or nerves, often caused by manual handling, repetitive movement or awkward posture. These conditions frequently develop gradually rather than from a single event.

Designing tasks, equipment and workstations to fit the people who use them, reducing strain and fatigue. Good ergonomics covers seating, screen height, reach distances and the pace of repetitive work.

Any chemical, dust, fume, vapour or biological agent that can harm health if inhaled, swallowed or absorbed through the skin. Safe use depends on knowing the substance, its route into the body and its exposure limits.

A standard document supplied with a hazardous substance that describes its hazards, safe handling, first aid and emergency measures. It supports the risk assessment but does not replace it.

An assessment of the risks from hazardous substances used or produced at work, and of the controls needed to prevent or adequately control exposure. It records the substance, the exposure route, the controls and any monitoring or health surveillance required.

Face masks and respirators that filter or supply clean air to protect the wearer from dust, fumes or vapours. They need face-fit testing, correct storage and maintenance, and only work as part of a wider control programme.

Sound loud enough to damage hearing or create safety risks by masking warnings and speech. Hearing damage is usually permanent and gradual, so exposure limits and hearing protection zones are used to control it.

Earplugs, earmuffs or similar devices worn to reduce the level of noise reaching the ear. They protect only the wearer and must be correctly fitted and worn for the whole time of exposure.

The hazards arising from contact with live conductors, faulty equipment or damaged cables, including shock, burns and fire. Controls include isolation, inspection and testing, residual current devices and keeping equipment dry and undamaged.

Isolating a power source and physically locking it so equipment cannot be re-energised or restarted while someone works on it. Only the person who fitted the lock should remove it.

A physical barrier around a dangerous part of a machine that prevents access to moving parts. Fixed guards are preferred; interlocks may be used where access is needed, and guards must never be bypassed.

Measures that prevent contact with moving parts, entanglement, ejection or unexpected start-up. It combines guarding, interlocks, emergency stops, isolation for maintenance and adequate training.

Risks from vehicles, forklifts and mobile plant moving around a site, especially where they share space with pedestrians. Segregated routes, marked walkways, speed limits and trained operators reduce the chance of collision.

A manoeuvre that causes many workplace fatalities because drivers have limited visibility behind them. Controls include avoiding reversing, one-way systems, trained banksmen, reversing alarms and mirrors.

An enclosed or partly enclosed space where dangerous atmospheres, engulfment or heat can occur, such as tanks, pits and sewers. Entry normally needs a permit, atmospheric testing, rescue arrangements and a trained team.

Testing the air in a space for oxygen level, flammable gas and toxic contaminants before and during entry. Results decide whether entry is safe or whether ventilation and breathing apparatus are needed.

Keeping the workplace clean, tidy and free from obstruction, with materials stored safely and waste removed promptly. Good housekeeping prevents slips, trips, fires and falling objects and makes hazards easier to see.

Preventing fires by controlling ignition sources and fuel, and preparing for them with detection, alarms, extinguishers, escape routes and drills. Everyone must know how to raise the alarm and where to assemble.

The planned actions people take when something goes wrong, such as fire, spillage, injury or evacuation. It covers alarms, escape routes, assembly points, first aid and who takes charge.

Immediate help given to an injured or ill person before professional treatment arrives. Workplaces need trained first aiders, suitable equipment and clear information about how to summon help.

Standard shapes and colours that warn of hazards, require certain behaviour, show escape routes or mark fire equipment. They support other controls but cannot replace them, and must be understood by everyone present.

A formal written authorisation for high-risk tasks such as hot work or confined space entry, setting out the hazards, precautions and time limits. It is signed by an authorised person and closed when the job is finished.

Visible commitment from managers and supervisors who set standards, resource controls and model safe behaviour. Leadership shapes culture more than written rules alone.

How well an organisation controls risk, measured by indicators such as incident rates, audit results and near-miss reports. Both lagging outcomes and leading activities should be tracked.

A proactive measure of safety activity, such as the number of inspections completed, training hours or hazards reported. It signals future performance rather than recording past failures.

A reactive measure of what has already happened, such as accidents, lost-time injuries or enforcement notices. Useful for trend analysis but slow to reveal current weaknesses.

The process by which anyone can tell the organisation about a hazard or near miss so it can be assessed and controlled. Good reporting depends on simple routes, no blame and visible feedback.

A structured review of an accident or near miss to find underlying causes and prevent recurrence. The aim is learning, not blame, so people feel able to give full information.

A regular, planned check of the workplace against agreed standards to spot hazards and confirm controls are working. Findings should be recorded, assigned to someone and followed up.

A systematic, usually independent review of safety management arrangements, procedures and records. It judges whether systems are in place and effective, rather than checking physical conditions alone.

A short, focused briefing to a work team on a specific hazard, task or lesson learned. It is most effective when it invites discussion and relates directly to the job in hand.

Planned learning that gives people the knowledge, skills and awareness to work safely, including induction, task training and refresher sessions. Its effectiveness should be checked, not just attendance recorded.