APS Risk Management

The National Fire Protection Association (NFPA) specifies a
system for identifying the hazards associated with materials.

The hazard identification signal is a color-coded array of four
numbers or letters arranged in a diamond shape. The blue, red,
and yellow fields (health, flammability, and reactivity) all use a
numbering scale ranging from 0 to 4. A value of zero means that
the material poses essentially no hazard; a rating of four
indicates extreme danger. The fourth value - white- shows
special precautions - either water reactive or an oxidizing agent.

Red--Flammability Hazard

4 - Materials with a flashpoint below 73°F and a boiling point
above 100°F - Materials that will rapidly or completely vaporize
at atmospheric pressure and normal ambient temperature, or
that are readily dispersed in air and that will burn readily.
Example, propane gas.

3 - Materials with a flashpoint below 73°F and a boiling point
greater than or equal to100°F, or a flashpoint above 73°F and
less than 100°F - Liquids and solids that can be ignited under
almost all ambient temperature conditions. Example, gasoline.

2 - Materials with a flashpoint above 100°F, but not exceeding
200°F - must be moderately heated or exposed to relatively high
ambient temperature before ignition can occur. Example, diesel
fuel oil.

1 - Materials with a flashpoint above 200°F - must be pre-heated
to burn. Example, corn oil.

0 - Materials which normally won't burn

Blue--Health Hazard

4-Materials with an oral LD50 of less than or equal to 5 mg/kg -
Material that on very short exposure could cause death or major
residual injury. Example: hydrogen cyanide.

3-Materials with an oral LD50 above 5, but less than 50 mg/kg -
Material that on short exposure could cause serious temporary or
residual injury. Example: chlorine gas.

2-Materials with an oral LD50 above 50, but less than 500 mg/kg
- Material that on intense or continued but not chronic exposure
could cause temporary incapacitation or possible residual injury.
Example: ammonia gas.

1-Materials with an oral LD50 above 500, but less than 2000
mg/kg - Material that on exposure would cause irritation but only
minor residual injury. Example: turpentine.

0-Materials with an oral LD50 above 2000 mg/kg - Material that
on exposure under fire conditions would offer no hazard beyond
that of ordinary combustible material. Example: peanut oil.

Yellow--Reactivity Hazard

4-Material is capable of explosion or detonation at normal
temperature and pressure. Example: trinitrotoluene (TNT).

3-Material is capable of explosion, but requires a strong initiating
source, or the material reacts explosively with water. Example:
fluorine gas.

2-Material undergoes violent chemical changes at elevated
temperature and pressure or which reacts violently with water or
which may form explosive mixtures with water. Example: calcium
metal.

1-Normally stable, but can become unstable at elevated
temperatures and pressures. Example: phosphorus (red or
white).

0-Normally stable - Material that in itself is normally stable, even
under fire exposure conditions, and is not reactive with water.
Example, liquid nitrogen.

White -- Special Precautions

W - Material shows unusual reactivity with water (i.e. don't put
water on it). Example: magnesium metal

OX - Material possesses oxidizing properties.