Flammable & Combustible Liquids

The use and storage of flammable and combustible liquids must comply with State Fire Marshal Division rules. This page is a guide to the most common regulations relating to flammable and combustible liquids.


Combustible: A liquid with a flash point over 100°F (38°C) is considered combustible.

  • Examples: diesel fuel, motor oil.
  • Hazard: May produce ignitable vapors at elevated temperatures.

Flammable: A liquid with a flash point under 100°F is considered flammable. 

  • Examples: gasoline, acetone, toluene, diethyl ether, alcohols.
  • Hazard: May produce ignitable vapors at normal ambient temperatures.


  • Ensure that all stored containers are in good condition, closed and properly labeled.
  • Use flammable liquids and combustible liquids in a fume hood to prevent buildup of ignitable vapor/air mixtures or inhalation of toxic vapors or gases. 
  • Avoid placing ignition sources (hot materials, flames, or sparking equipment) in the general vicinity of these liquids. If possible, replace open flames by electrical heating.
  • Ground equipment likely to produce a static spark.
  • Implement additional safety precautions when flammable and combustible liquids are heated to or above their flash points.
  • Compressed or liquefied gases present special fire hazards. Refer to the EH&S Compressed Gas Guidelines.

Contact between incompatible chemicals presents a serious fire risk. Proper handling and storage procedures should be followed. 

Storage Cabinets

No more than 10 gallons (37.9L) of flammable liquids may be kept outside of an approved storage cabinet at any time. Flammable and combustible liquid storage cabinets shall meet appropriate NFPA standards and may not be modified in any way. It is not recommended to ventilate storage cabinets. If not ventilated, storage cabinet vent openings shall be sealed with the bungs supplied with the cabinet. 

Safety Cans

Up to 5.3 gallons (20L) of flammable and combustible liquids may be stored in UL or FM listed safety cans. Safety cans must be constructed from metal and come equipped with a flame arrestor and spring-loaded caps on both the filling and pouring spouts to prevent spillage when dropped. The double-perforated metal surface of the flame-arrestor screen prevents flames from entering the container. Safety cans are available for both dispensing products and collecting waste. Safety cans shall not be modified. Many consumer portable fuel containers available at stores do not meet safety can standards.

Refrigerator Storage

Commercially available, domestic refrigerators contain built-in ignition sources and shall not be used to store flammable liquids or explosive chemicals. Light bulbs, switches, temperature controls, standard plugs, motor-starting relays, thermal-overload devices, and heater strips (for frost control) are all ignition sources.

Anyone who needs a refrigerator to store flammable liquids or explosives should use refrigerators specifically designed and approved for such use. Store flammable liquids requiring cool/cold storage in refrigerators/freezers manufactured for that purpose. Modification of general-purpose (domestic) refrigerators or freezers for flammable liquid storage is NOT permitted. Labels are available from EH&S.