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Materials Labeling and Signage

Hazardous waste label
Example of a hazardous waste label.

Container Labeling

Labeling is required by law. The container must provide the full name of the substance with no abbreviations. In addition, hazardous chemicals must also contain basic warning information. The basic warning information is the following: The chemical lab group the waste originated from, full name of the chemical waste (no abbreviations), percentage of chemical waste constituents to total 100%, hazardous designation (ignitable, toxic, reactive, or corrosive), and the full date when each bottle has been filled to 80% capacity.

When reusing a container, make sure you either remove or completely deface old labels to avoid confusion. Inspect labels and replace those that are hard to read or have fallen off. Good labeling practices avoids accidents and reduces the disposal cost of chemicals by eliminating subsequent unknowns.

National Fire Protection Association Labeling

NFPA uses a symbol system designed as a diamond-shaped label containing four differently colored squares. A number (0-4) or an abbreviation is added to each square indicating the order of hazard severity. The higher the number, the greater the hazard.

NFPA Labeling System

Red background = Flammability Yellow Background = Reactivity
4 – flash point < 73º F
3 – flash point < 100ºF
2 – flash point > 100ºF to < 200 ºF
1 – flash point > 200ºF
0 – will not burn
4 – Explosive at room temperature.
3 – Shock and heat may detonate
2 – Violent reaction with water
1 – Unsafe if heated, not violent
0 – Not reactive with water.
Blue Background = Health Hazard White Background = Specific Hazard
4 – Deadly
3 – Extreme danger
2 – Hazardous
1- Slightly hazardous
0 – Normal material
Oxidizer : OX
Acid: ACID
Alkali: ALK
Corrosive: CORR
Use No Water: W
Contact Information

Environmental Health and Safety

Office Location
  • Arthur M. Sackler Sciences Center
    Room S108
    950 Main Street
    Worcester, MA 01610
  • 1-508-793-7280
  • 1-508-793-7117 Fax
  • fabell[at]clarku[dot]edu