Graphology - the study of handwritings; autograph - written with one's own hand; seismograph - a machine noting strength and duration of earthquakes. marina - a harbor for pleasure boats; maritime - relating to the sea; submarine - an undersea boat; aquamarine - color of sea water.
Chemicals are classified into various hazard classifications in accordance with their physiochemical properties and health hazards. Each class of chemical has a pictorial symbol called a danger symbol.
Nine Classes of Hazardous Materials Class 1: Explosives Divisions: 1.1, 1.2, 1.3, 1.4, 1.5, 1.6 Class 2: Gases Divisions: 2.1, 2.2, 2.3. Class 3: Flammable Liquid and Combustible Liquid. Class 4: Flammable Solid, Spontaneously Combustible, and Dangerous When Wet . Divisions 4.1, 4.2, 4.3. Class 5: Oxidizer and Organic Peroxide. Divisions 5.1, 5.2