Safety exam glossary with cited definitions
48 terms that come up on the ASP, CSP and CHST. Each one quotes the regulation or federal document that defines it, then explains it plainly with an example.
Regulation quotes are checked word for word against the eCFR text we store. Checked 2026-10-16.
A
- Action levelAn exposure below the legal limit that triggers requirements such as monitoring, medical surveillance or hearing conservation.
- Affected employee (lockout/tagout)Someone who operates or works near equipment that's being serviced under lockout or tagout.
- Assigned protection factor (APF)How much protection a class of respirator is expected to give inside a working respiratory protection program.
- Attendant (confined space)The person stationed outside a permit space who watches the entrants and carries out the attendant duties.
- Authorized employee (lockout/tagout)The person who locks or tags out equipment to service or maintain it.
C
- Ceiling limit (C)An exposure limit that must never be exceeded at any time during the workday.
- Competent personSomeone who can recognize existing and predictable hazards and has the authority to correct them right away.
- Confined spaceA space big enough to enter and work in, with limited ways in or out, that isn't designed for people to stay in.
E
- Emergency response (HAZWOPER)A response by people from outside the immediate area to a release that is, or is likely to be, uncontrolled.
- Energy isolating deviceA mechanical device, such as a disconnect switch, valve or block, that physically stops energy from reaching equipment.
- Entry supervisorThe person who decides whether conditions are acceptable, authorizes entry into a permit space, oversees it and ends it.
- Exposure incident (bloodborne pathogens)A specific contact of blood or other infectious material with the eyes, mouth, mucous membranes or broken skin, or through the skin.
F
- Fault tree analysisA top-down method that starts from one undesired event and maps every credible combination of failures that could cause it.
- First aid (OSHA recordkeeping)The complete list of treatments in 1904.7(b)(5)(ii). A case treated only with these isn't recordable on treatment alone.
- Fit testA test of how well a tight-fitting respirator seals on a particular person, done qualitatively or quantitatively.
- Flammable liquidUnder OSHA, any liquid with a flashpoint at or below 199.4°F (93°C), split into four categories.
- FlashpointThe lowest temperature at which a liquid gives off enough vapor to form an ignitable mixture with air near its surface.
H
- Hazard (system safety)A real or potential condition that could lead to a mishap.
- Hazard statementThe set phrase on a label that describes the nature of a chemical's hazard and, where it applies, how severe it is.
- Hazardous atmosphereAir that could kill, injure, incapacitate or keep a worker from escaping, from one of five listed causes.
- Heat stressThe total heat load on a worker from body heat, the environment and clothing.
- Heat strokeA medical emergency where body temperature rises above about 106°F and the body's temperature control fails.
- Highly hazardous chemicalA toxic, reactive, flammable or explosive substance that brings a process under OSHA's Process Safety Management standard.
I
L
- Lagging indicatorA measure of past outcomes, such as injury rates or the number of fatalities.
- Leading indicatorA proactive measure of safety activity that can show problems before anyone is hurt.
- LockoutPutting a lock on an energy isolating device so the equipment can't run until that lock comes off.
M
- Maximum use concentration (MUC)The highest concentration a respirator can be used in: its APF multiplied by the exposure limit.
- Medical treatment (OSHA recordkeeping)Managing and caring for a patient to combat disease or disorder, excluding observation, diagnostic procedures and first aid.
- MishapAn event or series of events that causes unintentional death, injury, illness, property loss or environmental damage.
N
O
P
- Permit-required confined spaceA confined space with at least one serious hazard, such as a possible hazardous atmosphere, engulfment or entrapment.
- Pictogram (GHS)A symbol in a red diamond on a chemical label that shows the type of hazard. OSHA designates eight.
- Point of operationThe part of a machine where work is actually done on the material.
Q
R
- Recordable injury or illnessA work-related case that results in death, days away, restricted work or transfer, medical treatment beyond first aid, loss of consciousness, or a significant diagnosis.
- Restricted work (OSHA recordkeeping)When a work injury keeps someone from routine job functions or a full workday, by employer decision or medical recommendation.
- Risk (system safety)The combination of how severe a mishap would be and how likely it is to happen.
S
- Safety data sheet (SDS)The document for a hazardous chemical, prepared under the Hazard Communication Standard, with 16 set sections.
- Signal wordDanger or Warning on a chemical label: Danger for the more severe hazards, Warning for the less severe.
- Standard threshold shift (STS)A hearing change of 10 dB or more on average at 2,000, 3,000 and 4,000 Hz in either ear, compared with the baseline audiogram.
T
U
W
Formulas
For the math, see safety exam formulas with worked examples.
See where you stand
The free 25-question diagnostic scores you on every blueprint domain and shows the source behind each answer.