STS key terms

A condition, substance, or practice with the potential to cause injury, illness, property damage, or harm to the environment. A hazard exists whether or not anyone is currently exposed to it.

The combination of how likely a hazard is to cause harm and how severe that harm would be. Risk increases with greater exposure and decreases as effective controls are applied.

A ranked order for choosing safeguards: eliminate the hazard, substitute something safer, apply engineering controls, then administrative controls, and finally personal protective equipment. Higher-ranked controls are generally more reliable because they depend less on human behavior.

Physical changes to equipment, processes, or the workplace that reduce exposure at its source, such as ventilation, machine guards, noise enclosures, or lifting aids. They protect workers without relying on individual behavior.

Policies, procedures, schedules, and work practices that reduce exposure by changing how or when work is done, such as job rotation, permit systems, or limiting time in a hazard. They depend on consistent human compliance.

Equipment worn by a worker to create a barrier against a hazard, including gloves, respirators, hard hats, and hearing protection. It is the last line of defense and requires proper selection, fit, training, and maintenance.

A method of breaking a task into its steps, identifying the hazards at each step, and selecting controls before work begins. Results are often used to write safe work procedures and to train employees.

An unplanned event that did not cause injury or damage but had the potential to do so. Reporting near misses exposes failures in controls before someone is actually hurt.

A procedure for isolating hazardous energy such as electrical, mechanical, hydraulic, or pneumatic energy before servicing equipment, using locks and tags so the equipment cannot be started or energized unexpectedly.

An enclosed or partly enclosed space with limited entry and exit that is not designed for continuous occupancy, such as a tank, silo, or pit. Some require a permit because of atmospheric, engulfment, or entrapment hazards.

An organized set of policies, responsibilities, processes, and resources an organization uses to manage safety, with the goal of preventing harm and continually improving performance.

The shared values, beliefs, and behaviors that determine how safety is actually treated day to day, including what leaders reward and whether workers feel safe reporting problems.

A proactive measure of safety activities or conditions before harm occurs, such as inspections completed, training hours delivered, or hazards corrected. It signals whether prevention efforts are working.

A measure of outcomes that have already occurred, such as injury counts, days lost, or incident rates. It shows results but cannot by itself predict future safety performance.

A group of management and worker representatives that meets regularly to review hazards, incidents, and safety program results and to recommend improvements. Its value depends on real authority and follow-through.

The practice of defining who is responsible for specific safety duties and then holding people to those expectations through feedback, recognition, and fair, consistent consequences.

A four-step improvement cycle used to manage safety processes: set goals and plan, implement the plan, measure and check results, then act to standardize what worked or correct what did not.

A catch-all legal requirement that employers furnish a workplace free from recognized hazards likely to cause death or serious physical harm, even when no specific standard addresses that hazard.

Voluntary technical standards developed and agreed upon by experts and industry groups, such as ANSI, NFPA, and ASTM documents. They often become enforceable when adopted by regulation or written into contracts.

A legal limit on the amount or concentration of a substance in workplace air to which a worker may be exposed, usually expressed as a time-weighted average over an eight-hour shift.

The rule requiring employers to evaluate chemical hazards and communicate them through container labels, safety data sheets, and worker training so employees can handle chemicals safely.

A standardized document with sixteen sections describing a chemical's hazards, safe handling, first aid, and emergency measures. Employers must keep sheets accessible to exposed workers.

A required form on which an employer records work-related injuries and illnesses that meet the recording criteria, kept current and posted each year. Cases needing only first aid are not entered.

A work-related injury or illness requiring medical treatment beyond first aid, involving loss of consciousness, days away or restricted work, or a significant diagnosis. Such cases must be entered on the OSHA log.

A structured process for gathering facts about what happened, how, and why after an incident so that underlying causes are corrected and recurrence is prevented. It focuses on system failures rather than assigning blame.

A method for tracing an incident beyond its immediate cause to the underlying system conditions, such as poor design, missing training, or weak procedures, that allowed the event to occur.

A specific change made to eliminate the cause of a problem, assigned to an owner with a due date, such as repairing equipment, revising a procedure, or retraining. Completion is tracked and verified for effectiveness.

The number of recordable cases per 100 full-time workers over a period, calculated as recordable cases multiplied by 200,000 and divided by hours worked.

A rate covering only more serious cases involving days away from work, restricted duty, or job transfer, per 100 full-time workers, calculated as DART cases times 200,000 divided by hours worked.

A process for identifying which employees need which knowledge or skills by comparing job requirements with current competence, so that training effort and resources go where the gaps are greatest.

A short, focused safety discussion held with a work crew before or during a shift about a specific hazard, task, or recent incident. It is brief, interactive, and tied to that day's work.

Guidelines for teaching adults effectively: content must be relevant and practical, learners need active participation, and new material should build on existing experience and be applied quickly.

A questionnaire measuring how workers view management commitment, reporting, training, and other safety climate factors. Results reveal gaps between what leaders intend and what employees actually experience.

A written plan describing how to report an emergency, who directs the response, the evacuation routes and assembly areas, and how people are accounted for afterward.

A practice exercise in which occupants follow the emergency plan and leave the building or area. Drills test alarms, routes, and assigned roles and reveal weaknesses before a real event occurs.

A protective action in which people remain inside a building and seal it against an outdoor hazard, such as a chemical release or severe weather, instead of evacuating the area.

A standardized, scalable management structure used to organize emergency response, assigning clear roles such as incident commander, operations, planning, logistics, and finance.

An acronym for operating a fire extinguisher: Pull the pin, Aim at the base of the fire, Squeeze the handle, Sweep side to side. It applies only to small fires with a clear exit behind you.