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.
The extinguishing agents in Class B fire extinguishers may contain dry chemical agents. Class B extinguishers may contain an agent of either potassium bicarbonate or sodium bicarbonate. Cloth, paper, plastic, rubber, and wood are combustibles with potential to smolder and later reignite after the CO2 has dissipated.