Recognition, Identification, and Classification of Hazardous Materials
Recognition before identification
Recognition is noticing that something is wrong; identification is naming the material. Use multiple independent clues: occupancy and type of business, container shape and size, placards and labels, shipping papers and Safety Data Sheets, facility markings such as NFPA 704 and pipeline markers, and sensory clues gathered only from a safe distance - never deliberately smell a product, and never enter a plume to read a label.
Classification and the ERG
DOT organizes hazmat into nine classes: 1 explosives, 2 gases (2.1 flammable, 2.2 nonflammable, 2.3 toxic), 3 flammable and combustible liquids, 4 flammable solids and water-reactive materials, 5 oxidizers and organic peroxides, 6 toxic and infectious substances, 7 radioactive, 8 corrosives, 9 miscellaneous. The Emergency Response Guidebook works in a fixed order: yellow-bordered pages for the 4-digit UN/NA identification number, blue-bordered pages for the material name, then the orange guide page, and finally the green pages for isolation and protective action distances when the guide is so highlighted.
Traps
- Reading the orange-panel 4-digit number as a guide number. It is an ID number; the guide is a three-digit page reference.
- Reversing NFPA 704 colors: blue is health, red is flammability, yellow is instability, white is special hazards.
- Believing a placard is required on every package. Placards apply mainly to bulk and to quantities at or above the 1,001 lb aggregate threshold; small packages may show labels only.
- Assuming a container's shape tells you the exact product. Shape narrows the family; it does not name the chemical.
Rule of thumb
Identify from a distance using at least two independent clues and confirm with the ERG before anyone acts.