The red portion of the NFPA diamond represents fire hazards. The fire classification system for NFPA is as follows:

0 - Will not burn

1 - Must be preheated for ignition; flashpoint above 200°F (93°C)

2 - Must be moderately heated for ignition, flashpoint above 100°F (38°C)

3 - Ignition may occur under most ambient conditions, flashpoint below 100°F (38°C)

4 - Extremely flammable and will readily disperse through air under standard conditions, flashpoint below 73°F (23°C)

A laboratory labels its secondary containers of hazardous chemicals using a color-coded system, with a different color representing each different type of hazard. The coding system follows the color-coding used by the National Fire Protection Agency's "fire diamond." What hazard would be represented by the red section on the hazard label?