Environmental Health and Safety

MSDS Glossary

ACGIH
American Conference of Governmental Industrial Hygienists. An organization of professionals in governmental agencies or educational institutions engaged in occupational safety and health programs. ACGIH develops and publishes recommended occupational exposure limits for chemical substances and physical agents. See TLV.
Acid
A substance that produces hydrogen ions (H+) in aqueous solutions. An acid will destroy human tissue on contact. The pH values of acids are between 0 and 6. Strong acids have a lower pH and are more corrosive than weak acids. Examples of strong acids include hydrochloric acid, nitric acid, and phosphoric acid. See also pH, Bases, Corrosive.
Acute Effects
Adverse symptoms that occur immediately or shortly after an exposure to a chemical. Common symptoms of acute exposure include headache, dizziness, or nausea.
Acute Toxicity
Acute effects resulting from a single dose of, or exposure to, a substance.
Aerosol
A fine suspension in the air of small particles (e.g., smoke or fog).
Air-Purifying Respirator
A respirator that uses chemicals to remove specific gases and vapors from the air or that uses a mechanical filter to remove particulate matter. An air-purifying respirator must only be used when there is sufficient oxygen to sustain life and the air contaminant level is below the concentration limits of the device. See also Chemical Cartridge Respirator.
Alkali
See Base.
Allergic Reaction
An abnormal response by the body to chemical or physical stimuli (e.g., hives, sneezing).
Anesthetic
A chemical that causes a total or partial loss of sensation. Overexposure to anesthetics can cause impaired judgment, dizziness, drowsiness, headache, unconsciousness, and even death. Examples include alcohol, paint remover, and degreasers.
ANSI
American National Standards Institute is a privately funded, voluntary membership organization that identifies industrial and public needs for national consensus standards and coordinates development of such standards.
Antidote
A remedy to relieve, prevent, or counteract the effects of a poison.
Appearance
A description of a substance at normal room temperature and normal atmospheric conditions. Appearance includes the color, size, and consistency of a material.
Aquatic Toxicity
The adverse effects to marine life that result from being exposed to a toxic substance.
Asphyxiant
A vapor or gas that can cause unconsciousness or death by suffocation due to lack of oxygen. Most simple asphyxiants are harmful to the body only when they become so concentrated that they reduce oxygen in the air to dangerous levels of 18 percent or lower. The normal level of oxygen in the air is about 21 percent. Asphyxiation is one of the principal potential hazards of working in confined and enclosed spaces.
Asymptomatic
Showing no symptoms.
Atm
Atmosphere, a unit of pressure equal to 760 mmHg (mercury) at sea level.
Auto-Ignition Temperature
The minimum temperature at which a substance can ignite without a spark or a flame. Some examples: acetone 538°C (1000°F), ethyl ether 180°C (356°F), phenol 715°C (1319°F).

Return to top