OHST key terms

A ranked order for reducing risk: elimination, substitution, engineering controls, administrative controls, then personal protective equipment. Higher levels protect more people and depend less on individual behavior, so they are preferred whenever feasible.

A step-by-step review of a task that lists each step, identifies the hazards present, and specifies controls before work begins. The results feed safe work procedures and training content.

A proactive measure of safety activity or conditions, such as inspections completed, training hours, or corrective actions closed, that predicts future performance instead of reporting injuries that already happened.

A retrospective measure such as injury counts, lost-time days, or incident rates that shows what already occurred. It confirms trends but reveals problems only after harm has happened.

An injury rate computed by multiplying the number of OSHA recordable cases by 200,000 and dividing by hours worked, expressing recordables per 100 full-time-equivalent workers per year.

A structured method that traces an incident beyond immediate causes to the underlying system and management failures that allowed it, so corrective actions prevent recurrence rather than just fixing the moment.

The shared values, beliefs, and behavior about risk that determine how people act when unsupervised, visible in reporting willingness, accountability, and the priority managers give to safety over production.

An unplanned event that caused no injury or damage but had the potential to, treated as free evidence that a control failed and worth reporting and investigating.

The legal airborne concentration limit set by OSHA that a worker may be exposed to over a stated period, usually an eight-hour time-weighted average, enforceable as a regulation.

An advisory exposure guideline published by ACGIH describing conditions under which nearly all workers may be repeatedly exposed without adverse health effect; it is not a legal limit.

An average airborne concentration over a defined period, typically eight hours, calculated by weighting each measured concentration by the time the worker spent at that level.

A 15-minute average concentration that should not be exceeded at any point in the workday, capping brief high exposures that a full-shift average would mask.

A concentration that must never be exceeded at any instant, applied to fast-acting substances whose health effects appear within seconds or minutes of exposure.

Required when noise exposure reaches 85 dBA as an eight-hour average; includes exposure monitoring, annual audiometric testing, hearing protection, training, and recordkeeping.

A hearing test that establishes a baseline and is repeated annually to detect threshold shifts early, before occupationally induced hearing loss becomes disabling.

The level of protection a properly fitted class of respirator is expected to provide in the workplace, used to divide the exposure concentration and confirm the respirator is adequate.

A heat stress index combining dry-bulb, natural wet-bulb, and globe temperatures to estimate the combined effect of air temperature, humidity, and radiant heat, guiding work-rest schedules.

Estimating how likely and how severe harm from an identified hazard could be, then comparing that result with a tolerance criterion to decide whether and what controls are needed.

A grid plotting likelihood against severity to sort risks into levels such as low, medium, and high, so limited resources go first to the hazards that could hurt the most people.

A physical change to equipment, process, or workplace such as local exhaust ventilation, machine guarding, enclosure, or material substitution that reduces the hazard at its source without relying on worker behavior.

A procedural or scheduling measure such as job rotation, training, permit systems, or housekeeping rules that lowers exposure by changing how or how long work is done.

Equipment worn by the worker, such as gloves, respirators, hearing protection, or fall harnesses, that shields the body from a hazard and serves as the last line of defense after other controls.

A written procedure using locks and tags on energy-isolating devices to hold equipment in a de-energized state and release stored energy before service or maintenance.

A document authorizing entry into a space with limited entry or exit that is not designed for continuous occupancy, recording atmospheric tests, attendant assignment, and rescue arrangements required before entry.

A sixteen-section document supplied by the chemical manufacturer that gives hazard identification, exposure limits, safe handling, and emergency response information under the hazard communication standard.

A written plan describing reporting procedures, evacuation routes and assembly areas, accountability methods, and rescue or shutdown duties so employees know what to do when an emergency strikes.

The four elements required for combustion: fuel, oxygen, heat, and an uninhibited chemical chain reaction. Removing any one of them extinguishes the fire.

The lowest temperature at which a liquid releases enough vapor to form an ignitable mixture with air near its surface; it drives flammable liquid classification and storage rules.

A written authorization issued before welding, cutting, grinding, or other spark-producing work, confirming combustible clearance, fire watch, and extinguisher readiness for the duration of the task.

Directing occupants to remain indoors, close windows and outside air intakes, and seal into a room when leaving the building would expose them to a greater outdoor hazard.

A discussion-based drill in which participants talk through a simulated emergency to test plans, roles, and communications without moving equipment or personnel.

An element of an organization's activities, products, or services that interacts or can interact with the environment, such as a solvent emission, fuel storage, or wastewater discharge.

The international standard for environmental management systems, following plan-do-check-act: identifying aspects and legal requirements, setting objectives, applying operational controls, monitoring, and management review.

A plan required for facilities storing defined volumes of oil, specifying containment, inspection, and response procedures so a release cannot reach navigable waters.

The multi-copy shipping document tracking hazardous waste from generator through transporter to the receiving facility, verifying delivery and closing the cradle-to-grave chain of custody.

A plan that identifies industrial activities exposed to rain, selects best management practices, and sets inspection and monitoring duties to keep pollutants out of stormwater runoff.

The release amount of a hazardous substance that triggers immediate notification to federal, state, and local authorities, with written follow-up reports required afterward.