NFPA Rating System
HEALTH (Blue)
4
Deadly: Even the slightest exposure to this substance would be life threatening.
Only specialized protective clothing, for these materials, should be worn.
3
Extreme Danger: Serious injury would result from exposure to this substance.
Do not expose any body surface to these materials. Full protective measures should be taken.
2
Dangerous: Exposure to this substance would be hazardous to health. Protective measures are indicated.
1
Slight Hazard: Irritation or minor injury would result from exposure to this substance.
Protective measures are indicated.
0
No Hazard: Exposure to this substance offers no significant risk to health.
FLAMMABILITY (Red)
4
Flash Point Below 73° F: This substance is very flammable, volatile or explosive depending on its state.
Extreme caution should be used in handling or storing these materials.
3
Flash Point Below 100° F: Flammable, volatile or explosive under almost all normal temperature conditions.
Exercise great caution in storing or handling these materials.
2
Flash Point Below 200° F: Moderately heated conditions may ignite this substance.
Caution procedures should be employed in handling.
1
Flash Point Above 200° F: This substance must be preheated to ignite.
Most combustible solids would be in this category.
0
Will Not Burn: Substances that will not burn.
REACTIVITY (Yellow)
4
May Detonate: Substances that are readily capable of detonation or explosion
at normal temperatures and pressures. Evacuate area if exposed to heat or fire.
3
Explosive: Substances that are readily capable of detonation or explosion by a strong initiating source,
such as heat, shock or water. Monitor from behind explosion-resistant barriers.
2
Unstable: Violent chemical changes are possible at normal or elevated temperatures
and pressures. Potentially violent or explosive reaction may occur when mixed with water.
Monitor from a safe distance.
1
Normally Stable: Substances that may become unstable at elevated temperatures and pressures
or when mixed with water. Approach with caution.
0
Stable: Substances will remain stable when exposed to heat, pressure or water.