Class Hazardous Locations Defined

This chart was taken from an OSHA document entitled Hazardous Class Locations. For a more detailed explaination of Classes, Divisions and Groups visit their website or http://www.osha.gov/doc/outreachtraining/htmlfiles/hazloc.html.

Summary of Class I, II, III Hazardous Locations
CLASSES	GROUPS	DIVISIONS
CLASSES	GROUPS	1	2
I Gases, vapors, and liquids (Art. 501)	A: Acetylene B: Hydrogen, etc. C: Ether, etc. D: Hydrocarbons, fuels, solvents, etc.	Normally explosive and hazardous	Not normally present in an explosive concentration (but may accidentally exist)
II Dusts (Art. 502)	E: Metal dusts (conductive,^and explosive) F: Carbon dusts (some are conductive,^and all are explosive) G: Flour, starch, grain, combustible plastic or chemical dust (explosive)	Ignitable quantities of dust normally are or may be in suspension, or conductive dust may be present	Dust not normally suspended in an ignitable concentration (but may accidentally exist). Dust layers are present.
III Fibers and flyings (Art. 503)	Textiles, wood-working, etc. (easily ignitable, but not likely to be explosive)	Handled or used in manufacturing	Stored or handled in storage (exclusive of manufacturing)