Section II. CHEMICAL FORMS AND EXPOSURE HAZARDS
Many work processes require the contact with hazardous chemicals. Having a
safe and healthful work environment means you must recognize potential chemical
hazards and protect yourself from them.
a. Categories. The Hazard Communication Standard defines two main
categories of chemical hazards:
(1) Physical hazards. Physical hazards are chemicals that cause
explosion, fires, violent chemical reactions, or other hazardous situations.
(2) Health hazards. Health hazards are chemicals that can cause illness
or injury when inhaled or swallowed, or through contact with the skin or eyes.
Basic Forms. All chemicals exist in one of three basic forms:
(1) Solids. Solids have a definite shape and can become airborne s dust
or fume particles.
(2) Liquids. Liquids take the shape of their container and can become
airborne as mists or vapors.
(3) Gasses. Gasses are easily compressed, expand to fill a container,
and become airborne when not contained.
Dust and Fumes. Both dusts and fumes are made up of tiny solid
particles. Mechanical operations like grinding and crushing produce dust. So does
transfer of powdered or fibrous solids and abrasive cleaning. Fumes form by vapor
condensation when solids are melted in operations like welding and metal casting.
d. Vapors. Vapors are formed above any exposed liquid surface. Heating a
liquid makes it vaporize more quickly. Mist is made up of tiny droplets that become
airborne when liquids are sprayed, agitated, or applied to a hot surface. Mists also form
when hot vapors cool in air and condense.
Exposure routes are ways that chemicals enter the body. There are four main
routes of exposure.