Communities & Groups
Publications & Resources
Career Center

Z94.13 - Occupational Health & Safety



SAFE. Relatively free from danger, injury, or damage or from the risk of danger.

SAFE WORKPLACE. One in which the likelihood of all identifiable undesired events are maintained at an acceptable level.

SAFETY. The art of performing any activity in the most accident-free manner. Relatively free from hazard.

SAFETY (CUT-OUT). An overload protective device in an electric circuit.

SAFETY BELT. A life belt worn by telephone line worker, window washers, construction worker, etc., attached to a secure object (telephone pole, window sill, anchor point, etc.) to prevent injury due to falling. A seat or torso belt securing a passenger in an automobile or airplane to provide body protection during a collision, sudden stop, air turbulence, etc.

SAFETY COUPLING. A friction coupling adjusted to slip at a predetermined torque, to protect the rest of the system from overload.

SAFETY EDUCATION (TRAINING). The transmission of knowledge, skills, attitudes, motivations, etc., concerning the safety requirements of operations, processes, environments, etc., to workers, supervisors, managers, and others.

SAFETY ENGINEERING. Safety engineering is concerned with the planning, development, improvement, coordination, and evaluation of the safety component of integrated systems of individuals, materials, equipment, and environments to achieve optimum safety effectiveness in terms of both protection of people and protection of property.


SAFETY GLASS. Impact resistant and shatterproof glass used as eye protection and for automobile windows, large architectural windows and doors. Also includes heat-treated glass that breaks into granules instead of sharp-edged strands.

SAFETY HELMETS. Rigid headgear of varying materials designed to protect the head, not only from impact, but from flying  particles and electric shock, or any combination of the three. Safety helmets should meet the requirements of ANSI Standard Z89.1, Protective Headware for Industrial Workers.

SAFETY LOCK. A lock which can be opened only by its own key. Often used to  lock out- the electrical energized sources used in equipment or machinery operation.

SAFETY PROFESSIONAL. An individual who, by virtue of specialized knowledge and skill and/or educational accomplishments has achieved professional status in the safety field, may also have been awarded or earned the status of Certified Safety Professional by the Board of Certified Safety Professionals.

SAFETY RULE. A rule prescribing safeguarding requirements, personal protective equipment, or safe behavior on the job.

SAFETY RULES. Codes of conduct to avoid injury and damage.

SAMPLE. A number of sampling units from the population of units eligible to be included.

SAMPLING (GENERAL). The collection of samples of contaminants in air in the general work environment for a specified length of time. 

SAMPLING (GRAB). The collection of samples of contaminants in air in a work environment for small time periods (usually 5 min. or less). 

SAMPLING (PERSONNEL). The collection of samples of contaminants in air for the duration of the specific part of an operation by attaching an instrument or device to the worker. 

SAMPLING (STATISTICAL). A procedure in which primary sampling  units (e.g., municipalities) are first selected from a population, and then secondary units (e.g., city blocks) are sampled from within each chosen primary unit.  This may be extended so that tertiary units (e.g., households) or further units (individuals) are selected within the secondary units. 

SAMPLING UNIT. The basic unit (e.g., person, household, etc.) around which a sampling procedure is planned. 

SARCOMA. A malignant neoplasm arising from connective tissue cells.

SCAN. A shortened form of scintiscan - variously designated according to the organ under examination (e.g., brain scan, lung scan, etc.). Scanning refers to the visual examination of a small area in some detail. 

SCHEDULE RATING. A type of rating assigned under the Industrial Compensation Rating Schedule, as approved by the insurance commissioner, by which the Basic Manual Rate is modified to fit the physical conditions related to guarding of machines. It is also affected by the compliance of a safety organization to prescribe insurance standards. Not used in most states any longer.

SCHEDULED CHARGE. The specific charge (in days) assigned to a permanent partial, permanent total, or fatal injury.

SCREENING TEST. A test or series of tests to which an individual submits to determine whether enough evidence of a disease exists to warrant a further diagnostic examination.

SECONDARY ATTACK RATE. The number of new cases of disease which occur over a relatively short period of time within households in which there is a first or primary case of the disease per unit susceptible population in households with primary cases. 

SECULAR TRENDS. Changes in incidence rates, mortality rates, and other indicators of disease or injury frequency that occur gradually over relatively long periods of time. 

SELF INSURANCE. A term used to describe the assumption of one's own financial risk.

SELF-CONTAINED BREATHING APPARATUS (SCBA).  A respiratory protection device that consists of a supply of respirable air, oxygen, or oxygen-generating material worn by the worker.    

SENSITIVITY. The extent to which a test identifies as  positive all individuals who have a given disease. 

SERIOUS INJURY. The classification for a work injury which includes: (1) all disabling work injuries, (2) nondisabling injuries in the following categories: (a) eye injuries from work-produced objects, corrosive materials, radiation, burns, etc., requiring treatment by a physician, (b) fractures, (c) any work injury that requires hospitalization for observation, (d) loss of consciousness (work related), and (e) any other work injury (such as abrasion, physical or chemical burn, contusion, laceration, or puncture wound) which requires: 1) treatment by a medical doctor, or 2) restriction of work, or motion or assignment to another regularly established job.

SERIOUS INJURY FREQUENCY RATE. The number of serious injuries, as defined in ANSI Z16  per 1,000,000 employee-hours of exposure. When serious injury frequency rate is used, it should be clearly identified as serious injury frequency rate, to avoid confusion with other frequency rates. This rate relates serious injuries, as defined, to the employee-hours worked during the period and expresses the number of such injuries in terms of million-hour units by use of the following formula:  SIFR = Number of serious injuries x 1,000,000 /   Employee-hours of exposure.

SERIOUS VIOLATION. Any violation in which there is a substantial probability that death or serious physical harm could result from the violative condition. (OSHAct.)

SEVERITY RATE. The total days charged for work injuries as defined in ANSI Z16  per 1,000,000 employee-hours exposure. Days charged include actual calendar days of disability resulting from temporary total injuries and scheduled charges for deaths and permanent disabilities. These latter charges are based on 6,000 days for a death or permanent total disability, with proportionately fewer days for permanent partial disabilities for varying degrees of seriousness. (See standard disabling injury severity rate.)  SR =  Total days charged for work injuries x 1,000,000 /  Employee-hours exposure.

SHAVER'S DISEASE. A condition of pulmonary fibrosis and emphysema attributed to inhalation of fumes consisting of alumina, silica, iron and other substances fused at 2000ºC.

SHOCK. (1) The rapid fall in blood pressure especially following injury, operation, or the administration of  anesthesia. (2) A sudden disturbance of mental equilibrium.

SHOP RULES (WORKING RULES). Either regulations established by an employer dealing with day-to-day conduct in the plant operations, safety, hygiene, records, etc., or working rules set forth in collective bargaining agreements and in some union constitutions.

SHORT TERM EXPOSURE LIMITS (STEL). A 15 minute time-weighted average exposure which should not be exceeded at any time during a work shift.

SICK LEAVE. Period of time during which a worker may be absent without loss of job or seniority if unable to work because of illness or accident. A paid sick leave plan provides for full or partial pay for such absence, usually up to a stipulated maximum. Sick leave plans differ from accident and sickness benefits, principally in that the former cover shorter periods of absence, usually provide higher pay, and are uninsured.

SIDEROSIS. A pneumoconiosis resulting from chronic exposure to iron oxide and silicon dioxide. 

SIEVERT (SV).   The SI unit of radiation dose equal to the absorption of one gray (Gy), 1 Sv = 100 rem.

SILICATES. Compounds made up of silicon, oxygen, and one or more metals with or without hydrogen. These dusts cause nonspecific dust reactions, but generally do not interfere with pulmonary function. 

SILICONES. A unique group of compounds made by molecular combinations of the element silicon or certain of its compounds with organic chemicals.  Produced in variety of forms, including silicone fluids, resins, and rubber.  Silicones have special properties such as water repellency, wide temperature resistance, high durability, and high dielectric strength. 

SILICOSIS. A fibrotic disease of the lungs caused by the chronic inhalation of dust containing silicon dioxide. 

SINGLE POINT FAILURE. A failure of a subunit which by itself will cause a failure of the system or equipment.

SINTERING. Process of making coherent powder of earthy substances by heating but without melting. 

SKIN CONTAMINATION. Irritations and infections to the skin such as dermatitis and poison ivy. These contaminations are classified as work injuries if they arise out of and in the course of employment.

SLOT VELOCITY. Linear flow rate of contaminated air through the openings in a slot-type hood.

SMOKE. An air suspension (aerosol) of particles, often originating from combustion or sublimation. Carbon or soot particles less than 0.1µm in size result from the incomplete combustion of carbonaceous material such as coal or oil.  Smoke generally contains droplets as well as dry particles. Tobacco, for instance, produces a wet smoke composed of minute tarry droplets. 

SOMATIC MUTATION. An alteration in the molecular arrangement of the inherited DNA of the chromosomes of the general body cells (as opposed to the germ cells) occurring spontaneously or by some abnormal form of external stimulus.

SONAROGRAPHY. Ultrasonic scan (q.v.) that provides a two- dimensional image corresponding to clear sections of acoustic interfaces in tissue. 

SONE. A unit used in judging the loudness of sounds.  One sone is defined as the level, at 1000 Hz, that is 40 dB above the subjects' threshold of hearing. The loudness of a given sound is rated by the listener as some multiple of the sone.

SONOMETER. An appliance for testing acuteness in hearing.

SORBENT. A material which removes gases and vapors from air passed through a canister or cartridge. 

SOUND. An oscillation in pressure, stress, particle displacement, particle velocity, etc., which is propagated in an elastic material, in a medium with internal forces (e.g., elastic, viscous), or the super-position of such propagated oscillations. Sound is also the sensation produced through the organs of hearing, usually by vibrations transmitted in a material medium, commonly air.

SOUND ABSORPTION. The change of sound energy into some other form, usually heat, in passing through a medium or on striking a surface. In addition, sound absorption is the property possessed by materials and objects, including air, of absorbing sound energy.

SOUND ANALYZER. A device for measuring the band-pressure level or pressure-spectrum level of a sound as a function of frequency.

SOUND INTENSITY. The average rate at which sound energy is transmitted through a unit area perpendicular to a specified point.

SOUND-LEVEL METER. An instrument for the direct measurement of sound pressure level.  Sound-level meters often are made with various filtering networks that measure the sound directly on A, B, C, etc., scales.  Sound-level meters may also incorporate octave-band filters for measuring sound directly in octave bands. 

SOUND PRESSURE LEVEL.  The weighted sound pressure in decibels.  The level, in decibels, of sound is 20 times the logarithm to the base 10 of the ratio of the pressure of this sound to the referenced pressure.  The reference pressure must be explicitly stated.  (See DECIBEL.)

SPASM. (1) Sudden, violent, involuntary contraction of muscle(s). (2) Sudden but transitory constriction of a passage, canal, or orifice.

SPECIFIC GRAVITY.  The ratio of the density of a material to the density of some standard material, such as water at a specified temperature, or (for gases) air at standard pressure and temperature.  Abbreviated sp. gr.  Also known as relative density.

SPECIFICITY. The extent to which a test identifies as negative all individuals who are free of a given disease. 

SPEECH PERCEPTION TEST. A measurement of hearing acuity by the administration of a carefully controlled list of words. The identification of correct responses is evaluated in terms of norms established by the average performance of normal listeners.

SPLASH-PROOF GOGGLES.  Eye protection constructed of noncorrosive material that fits snugly against the face, and has indirect ventilation ports.

SPONTANEOUS IGNITION. Ignition resulting from a chemical reaction in which there is a slow generation of heat from oxidation of organic compounds until the combustion or ignition temperature of the material (fuel) is reached. This condition is reached only where there is sufficient air for oxidation but not enough ventilation to carry away the heat as fast as it is generated.

SPRAIN. A joint injury in which some of the fibers of a supporting ligament are ruptured, but the continuity of the ligament remains intact.

SPRINKLER SYSTEM. A combination of water discharge devices (sprinklers), distribution piping to supply water to the discharge devices, or more sources of water under pressure, water flow controlling devices (valves), and actuating devices (temperature, rate of rise, smoke or other type device). The system automatically delivers and discharges water in the fire area.

SQUEEZE. This occurs in diving during increases in pressure from the failure or inability to equalize pressure in gas- filled spaces. It occurs most commonly in the middle ear (aerotitis media) due to eustachian tube dysfunction or the nasal sinuses (aerosinusitis) due to blockage of the ostia. Squeeze may also occur in carious or poorly restored teeth, in the lung in breath-hold diving, or in the mask, suit, or helmet. 


STANDARD MAN. A theoretical physically fit man of standard (average) height, weight, dimensions, and other parameters (blood composition, percentage of water, mass of salivary glands, to name a few); used in studies of how heat or ionizing radiation affects humans. 

STANDARDIZED MORTALITY RATIO (SMR). The ratio of the number of deaths observed in the study population to the number of deaths that would be expected if the study population had the same specific rates as the standard population, multiplied by 100. 

STANNOSIS. A condition due to inhalation of tin or tin oxide dust.  It is characterized by the appearance of nodules in the lungs on chest x-ray, but autopsy studies have shown no evidence of fibrosis. The condition at present is thought to be benign.

STENOSING TENOSYNOVITIS (TRIGGER OR SNAPPING FINGER).  A localized inflammation of the tendon sheath with localized swelling. The swollen tendon snaps back and forth through the narrowed sheath during flexion and extension.  The condition frequently occurs at the base of the thumb or fingers in workers who repeatedly grasp hard or push with the distal palm, causing points of pressure over the tendon sheaths. 

STRAIN. Overstretching or overexertion of some part of the body musculature. 

STRATIFIED SAMPLING. A procedure in which the population is divided into strata, or groups of units having certain characteristics in common, and a sample of units drawn from each stratum. 

SUBROGATION. The legal process by which a company endeavors to recover from a third party the amount paid to an insured under an insurance policy when such third party may have been responsible for the occurrence causing the loss.

SUPPLIED-AIR SUIT. A one- or two-piece suit that is impermeable to most particulate and gaseous contaminants and is provided with an adequate supply of respirable air. 

SURGICAL BENEFITS. Plans which provide employees, and in many cases their dependents, with specified surgical care or a cash allowance toward the cost of such care, usually in accordance with a schedule of surgeon's fees. Generally part of a health and insurance program  (See HEALTH AND INSURANCE PLAN.)

SURVEILLANCE. Ongoing scrutiny, generally using methods distinguished by their practicability, uniformity, and frequently their rapidity, rather than by complete accuracy. Its main purpose is to detect changes in order to initiate investigative or control measures. 

SURVEY. Inspection and comprehensive study or examination of an organization, environment or activity for insurance and/or accident prevention purposes.

SURVIVORS' BENEFITS (TRANSITION BENEFITS, BRIDGE BENEFITS, WIDOWS' ALLOWANCE). Payments to dependents of employees who die prior to retirement, financed in whole or in part by the employer. May be in the form of payments for a fixed period (e.g. 24 months) supplementing regular life insurance benefits, a benefit for life out of a pension program, a lump-sum payment, etc.

SYNERGISM. The interaction of two or more physiologically active agents producing an effect which is equal to (additive) or greater than (potentiation) the effect produced using equivalent doses of each agent presented individually. 

SYSTEM SAFETY. The application of operating, technical and management techniques and principles to the safety aspects of a system throughout its life to reduce hazards to the lowest level possible through the most effective use of available resources.

SYSTEM SAFETY ANALYSIS. The safety analysis of a complex process by means of a diagram or model that provides a comprehensive, overall view of the process, including its principal elements and the ways in which they are interrelated. There are four principal methods of analysis: failure mode and effect, fault tree, THERP, and cost-effectiveness. Each has a number of variations and more than one may be combined in a single analysis. (See FAILURE MODE AND EFFECT ANALYSIS, FAULT TREE ANALYSIS, THERP.)

SYSTEM SAFETY ENGINEERING. The application of scientific and engineering principles during the design, development, manufacture, and operation of a system to meet or exceed established safety goals.

SYSTEMATIC SAMPLING. A procedure in which the selected sampling units are spaced regularly throughout the population; that is, every nth unit is selected. 

< Previous |  Next >

Print: Share: