Hazardous chemicals present many potential dangers in the workplace, employees unable to read and understand chemical labels further increase these risks. This informational poster provides an overview of hazardous chemical labels.
“Understanding Hazardous Chemical Labels
There are two prevailing labeling systems used: The HMIS developed by the National Paint and Coatings Association and the NFPA created by the National Fire Protection Association. The two systems emphasize different aspects of hazardous chemical labeling, and employees need to understand the difference. Numerical ratings are also different and should not be interchanged.
HMIS Hazardous Material Identification System includes hazard evaluations, a rating system for acute and chronic health, flammability and reactivity. These labels provide at-a-glance information on the hazards and personal protective equipment. The chemical name is listed first. If the chemical has chronic health effects, an asterisk (*) will be placed in the first blue box. The remaining boxes will have numbers based on the severity of the hazard. The personal protection box will have a letter corresponding to the appropriate PPE to use as listed below. Sometimes the letter is replaced with icons of the needed PPE. Some HMIS labels will have a yellow box labeled “reactivity” instead of an orange “physical hazards” box. Other variations are also used but the basic format is still the same.
* chronic hazard chronic (long-term) health effects may result from repeated overexposure.
0 minimal hazard no significant risk to health.
1 slight hazard irritation or minor reversible injury possible.
2 moderate hazard temporary or minor injury may occur.
3 serious hazard major injury likely unless prompt action is taken and medical treatment is given.
4 severe hazard life-threatening, major or permanent damage may result from single or repeated overexposures.
0 minimal hazard materials that will not burn.
1 slight hazard materials that must be reheated before ignition will occur. Includes liquids, solids and semi-solids having a flash point above 200f (Class IIIB).
2 moderate hazard materials which must be moderately heated or exposed to high ambient temperatures before ignition will occur. Includes liquids having a flash point at or above 100f but below 200f (Class II & IIIA).
3 serious hazard materials capable of ignition under almost all normal temperature conditions. Includes flammable liquids with flash points below 73f and boiling points above 100f, as well as liquids with flash points between 73f and 100f. (Class IB & IC).
4 severe hazard flammable gases, or very volatile flammable liquids with flash points below 73f and boiling points below 100f. Materials may ignite spontaneously with air. (Class IA).
0 minimal hazard materials that are normally stable, even under fire conditions, and will not react with water, polymerize, decompose, condense or self-react. Non-explosives.
1 slight hazard materials that are normally stable. Can become unstable (self-react) at high temperatures and pressures. May react non-violently with water or undergo hazardous polymerization in the absence of inhibitors.
2 moderate hazard materials that are unstable and may undergo violent chemical changes at normal temperature and pressure with low risk for explosion. May react violently with water or form peroxides upon exposure to air.
3 serious hazard materials that may form explosive mixtures with water and are capable of detonation or explosive reaction in the presence of a strong initiating source. May polymerize, decompose, self-react or undergo other chemical changes at normal temperature and pressure with moderate risk of explosion.
4 severe hazard materials that are readily capable of explosive water reaction, detonation or explosive decomposition, polymerization or self-reaction at normal temperature and pressure.
Personal protection items
A safety glasses
B safety glasses, gloves
C safety glasses, gloves, protective apron
D face shield, gloves, protective apron
E safety glasses, gloves, dust respirator
F safety glasses, gloves, protective apron, dust respirator
G safety glasses, gloves, vapor respirator
H splash goggles, gloves, protective apron, vapor respirator
I safety glasses, gloves, vapor respirator, dust respirator
J splash goggles, gloves, protective apron, vapor respirator, dust respirator
K airline mask or hood, gloves, full suit, boots
L-z site specific PPE
NFPA is a fire protection hazard warning system designed to provide rapid, clear information to emergency responders on materials under conditions of fire, chemical spill or other emergency situations. The system addresses health hazards, flammability, instability and special hazards.
A number is placed in the blue, red, and yellow diamonds that corresponds with the chemical hazard of that category. A symbol is placed in the white diamond that corresponds with the special hazards of the chemical. See chart to the right.
- Very short exposure could cause death or major residual injury.
- Short exposure could cause serious, temporary or residual injury.
- Intense or continued but not chronic exposure could cause temporary incapacitation or possible residual injury.
- Exposure would cause irritation with only minor residual injury.
- Poses no health hazard, no precautions necessary.
- Will rapidly or completely vaporize at normal atmospheric pressure and temperature, or is readily dispersed in air and will burn readily. Flash point below 23°c (73°f).
- Liquids and solids that can be ignited under almost all ambient temperature conditions. Flash point below 38°c (100°f) but above 23°c (73°f).
- Must be moderately heated or exposed to relatively high ambient temperature before ignition can occur. Flash point between 38°c (100°f) and 93°c (200°f).
- Must be pre-heated before ignition can occur. Flash point over 93°c (200°f).
- Will not burn.
- Readily capable of detonation or explosive decomposition at normal temperatures and pressures.
- Capable of detonation or explosive decomposition but requires a strong initiating source, must be heated under confinement before initiation, reacts explosively with water or will detonate if severely shocked.
- Undergoes violent chemical change at elevated temperatures and pressures, reacts violently with water or may form explosive mixtures with water.
- Normally stable, but can become unstable at elevated temperatures and pressures.
- Normally stable, even under fire exposure conditions, and is not reactive with water.
‘w’ – reacts with water in an unusual or dangerous manner
‘oxy’ – oxidizer
‘cor’ – corrosive; strong acid or base
‘acid’ and ‘alk’ -used to indicate acid or base, more specific than corrosive
‘bio’ – biohazardous
‘cryo’ – cryogenic
Only ‘w’ and ‘oxy’ are official symbols of the NFPA 704. Other symbols are sometimes used and therefore added to this list. Check with local authorities (fire department) on the use of other symbols.”
This full color, laminated, safety poster is 18″ x 24″ with English or Spanish options available.