Any substance can be harmful to living things. Therefore proper caution must be used when handling all substances, especially those encountered in a chemistry laboratory.

There are four main routes by which hazardous materials enter the body:

• Absorption through the lungs via inhalation. This can result in severe harm!
• Absorption through the digestive tract, possibly by eating in a contaminated work area.
• Absorption through the skin.
• Injection through the skin. This can occur through misuse of sharp materials or through contact with wounds or broken skin.

Toxic effects can vary from mild and reversible to serious and irreversible:

• ACUTE poisoning can be caused by rapid absorption, usually of a single, large, sudden exposure.
• CHRONIC poisoning occurs by prolonged or repeated exposure but symptoms may not be immediately apparent.
• CUMULATIVE poisons tend to build up in the body by chronic exposures but, again, the effects may not be seen until a critical amount is present.
• SYNERGISTIC poisons are two or more hazardous materials which together have a much greater effect than expected from each substance alone.

Chemical Reactivity Hazards: Certain types of compounds react with each other to produce heat, gases, and hazardous products. Examples:

• Oxidizing agents react with reducing agents. [Organic tissue has reducing properties.]
• Acids react with bases. Both are corrosive. The heat of reaction usually causes a more severe hazard.
• Substances may react with water, including water vapor in the air.
• Substances may react with oxygen in air.

When handling chemicals:

• Keep your hands away from your face, eyes, and body until after they have been washed thoroughly.
• If you spill any chemical onto your skin, wash it away with plenty of fresh water.
• Do not taste any chemical.
• To sample the odor of a chemical, fan some vapor toward your nose with your hand, and sniff cautiously.
• Do not pipet anything by mouth.
• When diluting acids, pour the acid into the water, slowly and with agitation. NEVER POUR WATER INTO SULFURIC ACID. Instead, carefully add the acid to the water.
• When pouring from a bottle, hold the stopper so that it is not contaminated by foreign substances. Wash any chemicals from the outside of the bottle before returning it to its storage place. DO NOT RETURN UNUSED CHEMICALS TO STOCK BOTTLES.
• Mercury and its vapor are poisonous. Notify the instructor immediately in case of any spill, (such as a thermometer breakage). Do not pour mercury into the sink drain.

Chemical container labels usually give information about the toxic, flammable, corrosive, and reactive properties and potential hazards of the chemicals they contain. It is impreative to READ and HEED the LABEL. Not all hazards, however, may be covered on the label.

A Material Safety Data Sheet (MSDS) for each chemical is on file in our stockroom. This information is available for students to consult, but it can be voluminous and technical.  The meaning of some words used to describe health hazards in MSDS follows: