A formless substance that expands to occupy the space of its container (for example, methane, acetylene).


Glove cuff 4” or more in length which gets wider towards the end.

GFCI (Ground Fault Circuit Interrupter)

Device that protects people and equipment from ground faults or sudden equipment restarts after a power failure.


Bright light that interferes with a person’s ability to see. Glare causes discomfort and can lead to eyestrain and headaches.

Grain Leather

Smooth external side of the hide. Provides durability and dexterterity.


Electrical connection of one or more conductive objects to the earth through the use of metal grounding rods or other devices.


Use of any device or combination of devices designed to keep any part of a worker’s body out of the danger zone of a machine during its operating cycle. This usually involves guarding the point of operation, guarding power transmission components by fixed enclosures, and/or protecting the operator and nearby workers from flying fragments.



The potential of any machine, equipment, process, material (including biological and chemical) or physical factor that may cause harm to people, or damage to property or the environment.

Hazardous Material

Any substance that may produce adverse health and/or safety effects to people or the environment.


Light bulb which is brighter than fluorescent and krypton.


Lockout device designed to prevent accidental equipment start-up.

Health and Safety Policy

A policy is a statement of intent, and a commitment to plan for coordinated management action. A policy should provide a clear indication of a company’s health and safety objectives. This, in turn, will provide direction for the health and safety program.

Health and Safety Program

A systematic combination of activities, procedures, and facilities designed to ensure and maintain a safe and healthy workplace.

Heat Exhaustion

Overheating of the body. Heat exhaustion can happen when the body loses too much fluid (because of excessive sweating) or when conditions, such as physical activity in a hot environment, prevent sweat from evaporating into the air.

Heat Stroke

A potentially deadly condition in which over-exposure to a very hot environment breaks down the body’s ability to control its temperature and cool itself sufficiently.

Hearing Conservation

The prevention or minimizing of noise induced deafness through the use of hearing protection devices, the control of noise through engineering methods, annual audiometric tests and employee training.

HEPA (High Efficiency Particulate Air Filter)

At least 99.97% efficient against particulates down to a 0.3 micron diameter size. A P100 filter can be used in place of HEPA filters.


A way of controlling hazards along the path between the source and the worker. Good housekeeping means having no unnecessary items in the workplace and keeping all necessary items in their proper places. It includes proper cleaning, control of dust, disposal of wastes, clean-up of spills and maintaining clear aisles, exits, and work areas.

Human Error

This term is used today to include not just workers’ errors, but engineering deficiencies and lack of adequate organizational controls which together account for the majority of accidents.

Hygiene Practices

A broad term for personal health habits that may reduce or prevent the exposure of a worker to chemical or biological substances.


The condition of being reactive to substances that normally would not affect most people.


A condition in which body temperature drops below normal (36°C or 96.8°F). It most frequently develops from being exposed to very low temperatures. Hypothermia can cause death.


IDLH (Immediately Dangerous to Life and Health)

The maximum concentration of a chemical in the air to which one can be exposed (for up to 30 minutes) without suffering irreversible health effects when not using a respirator.


An unwanted event which, in different circumstances, could have resulted in harm to people, damage to property or loss to a process. Also known as a near miss.

Indirect Venting

Allows only air through goggles, not liquid or particles. Commonly used in chemical applications.

Indoor Air Quality (IAQ)

The study, evaluation and control of indoor air quality related to temperature, humidity and airborne contaminants.

Industrial Hygiene

A science that deals with the anticipation, recognition, evaluation, and control of hazards in the workplace. These hazards may cause sickness, harm to employee health, discomfort, and inefficient performance on the job. Also known as occupational hygiene.


The breathing in of an airborne gas, vapor, fume, mist or dust.


To force or drive liquid or gas into the body.

Injury Frequency Rate

The number of compensable injuries per 200,000 employee-hours of exposure. The following formula is used to calculate the injury frequency rate: Number of Compensable Injuries X 200,000 Hours Total Hours Worked.

Injury Severity Rate

A number that relates total days lost due to compensable injuries to the total hours worked during a specific period. The following formula is used to calculate the injury severity rate: Number of Days Lost X 200,000 Hours Total Hours Worked.

Intrinsically Safe

Product that won’t cause spark in an explosive environment.


A substance which, in sufficient quantities, can inflame or irritate the eyes, skin or respiratory system (lungs, etc.). Symptoms include pain and reddening.


Buffered to the same pH balance as the human eye.



Knitted material that is extremely soft and comfortable to wear.

Job Hazard Analysis

A technique used to identify, evaluate, and control health and safety hazards linked to particular tasks. A task analysis systematically breaks tasks down into their basic components. This allows each step of the process to be thoroughly evaluated.

Job Rotation

Moving an employee to one or more related jobs during a work shift.


Unit of energy used in describing a single pulse output of a laser.



Cut-resistant, flame retardant fiber offers heat resistance and is often used in clothing and gloves.


Knitted wristband prevents glove from falling off and debris from entering. Also keeps hands warmer.



Flexible line used to secure a body harness to a lifeline or anchorage point.


Liquid Crystal Display.

LED (Light Emitting Diode)

Electrical device used as an indicator light and in flashlights.

LEL (Lower Explosive Limit)

Minimum percent of a combustible gas that could cause an explosion if exposed to any source of ignition.

Level A Clothing

Should be worn when the highest level of respiratory, skin, and eye protection is needed.

Level B Clothing

Should be worn when the highest level of respiratory protection is needed, but a lesser level of skin protection.

Level C Clothing

Should be worn when using air purifying respirators.

Level D Clothing

Should be worn only as a work uniform and not on any site with respiratory or skin hazards.


Line provided for direct or indirect attachment to a worker’s body harness, lanyard, or deceleration device. Good for horizontal or vertical applications.


Restricted to one spot or area in the body and not spread throughout it.


A specific set of procedures for ensuring that a machine, once shut down for maintenance, repair or other reason, is secured against accidental start-up or movement of any of its parts for the length of the shutdown.

Loss Control

Measures taken to prevent and reduce loss. Loss may occur through injury and illness, property damage, poor work quality, etc.




Material Safety Data Sheet (MSDS)

A form that contains detailed information about the possible health and safety hazards of a product and how to safely store, use and handle the product. Under the federal Hazardous Products Act, suppliers are required to provide MSDSs for all hazardous materials, as a condition of sale.

Medical Surveillance

The systematic approach to monitoring health changes in workers to identify and determine which effects may be work-related.


Top part of the foot above the toes and below the shin bone.


Unit of measure for particle size. The smaller the number, the smaller the particle.


Type of fabric created with fibers that are thousands of times smaller than fibers in conventional fabrics. Provides exceptional pick-up ability.


Protective sole, usually made of steel, that protects the underside of the foot against punctures resulting from stepping on sharp objects.


Metal Inert Gas.


1/1,000 of an inch. Used in reference to glove thickness.


Small droplets of a liquid that can remain suspended in air. Mists can form when a vapor condenses back to its liquid state, or when a liquid breaks up.


Mining Safety and Health Administration.

Musculoskeletal Injuries

Injuries to the system of muscles, tendons, ligaments, joints, bones and related structures of the human body.

MUTCD (Manual on Uniform Traffic Control Devices)

Defines the standards used by road managers nationwide to install and maintain traffic control devices on all streets and highways.



Hand-held ball that produces a mist or cloud when squeezed. Used in fit testing applications.

Negative Pressure

Respirators that depend on wearer’s lung power to draw air through a filter material.


Synthetic rubber that is lightweight and flexible even in temperature extremes. Has a wide range of chemical and abrasion resistance.


National Fire Protection Association.


The standard for electrical safety in the workplace.


Nickel cadmium rechargeable battery.


Nickel metal hydride rechargeable battery.

NIOSH (National Institute for Occupational Safety and Health)

Independent federal agency which tests and certifies respirators.


Synthetic rubber resists a wide range of chemicals, as well as punctures, cuts, snags, and abrasions.


Unwanted sound that can lead to hearing loss or stress, or interfere with the ability to hear other sounds or to communicate.

Nose Cup

Part of a full face respirator that is designed to reduce fogging.

NRR (Noise Reduction Rating)

The number of decibels by which the surrounding noise level is reduced.

Nuisance Dust or Particle

Dust that does not cause disease or harmful effects when exposures are kept at reasonable levels.

Nuisance Level

Air concentration of a chemical below OSHA’s permissible exposure limit.


Occupational Illness

A harmful condition or sickness that results from exposure in the workplace due to a biological, chemical, or physical agent or an ergonomic hazard.

Occupational Safety

The maintenance of a work environment that is relatively free from actual or potential hazards that can injure employees.

OSHA (Occupational Safety and Health Administration)

Oversees and regulates workplace safety and health.


A form of oxygen that is an irritating, sharp-smelling gas. Prevalent when striking an arc while welding on aluminum, galvanized or stainless steel.


PAPR (Powered Air Purifying Respirator)

Respirator system that uses a blower motor to pull in air and distribute it through a hose to the facepiece.


Tiny pieces of dry or liquid matter.

PEL (Permissible Exposure Limit)

OSHA designated exposure limits to chemicals found in the air.

Personal Monitoring

A technique used to determine an individual’s personal exposure to a chemical, physical or biological agent. This is done by means of a sampling device worn on the worker’s body (e.g., personal monitor).

Personal Protective Equipment (PPE)

Any device worn by a worker to protect against hazards. Some examples are: respirators, gloves, earplugs, hard hats and safety glasses.


Material used for chemical and light impact protection.


A measure of the acidity or alkalinity of a substance on a scale of 0–14, where 7 is neutral. Less than 7 becomes more acidic. Greater than 7 becomes more alkaline.


Extremely impact resistant material that blocks out 99.9% UV rays.


Non-woven, lightweight plastic material that resists chemicals and moisture.


Breathable, non-woven, lightweight thermoplastic material.

Positive Pressure

Refers to respirators in which air is delivered by either pump, compressor, tank, or through a motor blower. Maintains a constant flow of clean air and prevents contaminants from entering.

PPM (Parts per Million)

Measures very low concentrations or contamination levels.


Used on air purifying respirators. Prefilter traps particles and helps prolong the life of the cartridge. May also be used without a cartridge.

Pressure Demand

A positive pressure respirator that regulates air flow only when a person breathes. Conserves limited air supplies.


Provides excellent abrasion resistance and limited chemical resistance.

PSI (Pounds per Square Inch)

Measurement of pressure exerted by a solid, liquid, or gas.

PVC (Polyvinyl Chloride)

Synthetic, abrasion-resistant material that protects against many acids, oils, fats, caustics, and petroleum hydrocarbons.