Environmental Health and Safety

MSDS Glossary

Self-Contained Breathing Apparatus
A respiratory protection device that consists of a supply or a means of respirable air, oxygen, or oxygen-generating material which is carried by the wearer.
Sensitizer
A chemical that causes a substantial proportion of exposed people or animals to develop an allergic reaction in normal tissue after repeated exposure to the chemical.
Silicosis
A disease of the lungs (fibrosis) caused by the inhalation of silica dust.
Skn
Skin.
"Skin"
A notation sometimes used with PEL or TLV exposure data that indicates that the stated substance may be absorbed by the skin, mucous membranes, and eyes, either by airborne or by direct contact.
Skin Absorption
Ability of some hazardous chemicals to pass directly through the skin and enter the bloodstream.
Skin Toxicity
See Dermal Toxicity.
Solubility in Water
A term expressing the percentage of a material (by weight) that will dissolve in water at ambient temperature.
Solvent
A substance, usually a liquid, in which other substances are dissolved. The most common solvent is water.
Specific Chemical Identity
The chemical name, Chemical Abstracts Service (CAS) Registry Number, or any precise chemical designation of a substance.
Specific Gravity
The weight of a material compared to the weight of an equal volume of water is an expression of the density (or heaviness) of a material. Insoluble materials with specific gravity of less than 1.0 will float on water. Insoluble materials with specific gravity greater than 1.0 will sink in water. Some flammable liquids have specific gravities greater than 1.0 and will sink in water. Most flammable liquids have specific gravities less than 1.0 and, if not soluble, will float on water, which is an important consideration for fire suppression.
Spill or Leak Procedures
The methods, equipment, and precautions that should be used to control or clean up a leak or spill.
Splash-Proof Goggles
Eye protection that fits snugly against the face, and may have indirect ventilation ports.
Spontaneously Combustible
Capable of catching fire without an ignition source. Can occur due to oxidation in air or by internal heat buildup.
Stability
The ability of a material to remain unchanged. For MSDS purposes, a material is stable if it remains in the same form under expected and reasonable conditions of storage or use. Conditions that may cause instability (dangerous change) are stated; for example, temperatures above 150°F; shock from dropping.
STEL
Short-Term Exposure Limit (ACGIH terminology). See TLV.
Subcutaneous
Beneath the layers of the skin.
Supplied-Air Respirators
Air line respirators or self-contained breathing apparatus.
Sys
System or systemic.
Systemic Poison
A poison that spreads throughout the body, affecting all body systems and organs. Its adverse effect is not localized in one spot or area.
Systemic Toxicity
Adverse effects caused by a substance that affects the body in a general rather than local manner.
Synonym
Another name or names by which a material is known. Methyl alcohol, for example, is also known as methanol or wood alcohol.

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