Flammable and Combustible Liquid Storage

 The storage of flammable and combustible liquids in a laboratory, shop, or building area must be kept to the minimum needed for research and operations.  Flammable liquids have a flash point below 100oF.  If more than 5 gallons of flammable liquids are stored outside safety cans per 100 square feet of area, a flammable-liquids storage cabinet is needed.  Flammable-liquids storage cabinets are not intended for storage of anything other than flammable liquids. 

The total quantity of flammable liquids permitted to be stored in a laboratory is 10 gallons per 100 square feet of laboratory space. 

The maximum quantities of flammable liquids and flammable gases listed above will be reduced on a case-by-case basis if in the opinion of the Health and Safety Officer, a hazard is created by having such a volume of flammable liquids present. 

Flammable Liquids Storage in a Cabinet 

1.  No more than 60 gallons of Class I flammable liquids (flash point below 100EF) or Class II combustible liquids (flash point between 100E to 140EF) may be stored in a flammable-liquids storage cabinet. 

2.  No more than 120 gallons of a Class III combustible liquid (flash point between 140EF and 200EF) may be stored in a flammable-liquids storage cabinet. 

3.  Storage cabinets shall be designed and constructed to limit the internal temperature to not more than 325EF when subjected to a 10-minute fire test using the standard time temperature chart set forth in NFPA 251. 

4.  All flammable-liquids cabinets shall be labeled in conspicuous letters "FLAMMABLE."

5.  Storage cabinets shall be constructed of at least No. 18 gauge sheet iron and shall be double walled with 1-1/2 inch air space.  Joints shall be riveted, welded, or made tight by some equally effective means.  The door shall be provided with a three-point lock, and the door sill shall be raised at lease 2 inches above the bottom of the cabinet. 

6.  All flammable liquid storage cabinets must be grounded.  A ground cable of 3/8" copper brain or a 12 gauge copper conductor can be used. 

The ground must be tested and resistance to ground cannot exceed one mega ohm.  The grounding cable must be connected to a building structural member or an electrical building ground.  Due to increased use of plastic piping, (which breaks the ground) water pipes must not be used for grounding. 

7.  The NFPA Technical Committee on General Storage of Flammable Liquids considers that providing vents to storage cabinets reduces the limited fire protection provided by such cabinets because a single walled duct will transmit heat faster than a double-walled cabinet.  Ventilation of storage cabinets is recommended only when highly odoriferous conditions exist.  Ventilation requires a steel duct and an appropriate exhaust fan discharging to an appropriate location outside the building. 

8.  All chemical storage in cabinets must be compatible. 

Flammable Liquids Storage Outside of a Cabinet 

Storage of flammable liquids outside of a storage cabinet should be avoided when possible.  Flammable liquids that are not in use should be stored in an appropriate cabinet. 

1.  The maximum quantity of flammable liquids allowed in a laboratory outside of a storage cabinet and not stored in a safety can is 5 gallons per 100 square feet of laboratory space. 

Transportation of Hazardous Chemicals 

The transportation of hazardous chemicals in laboratory buildings provides the greatest potential for chemical exposure to the building occupants.  Spills occurring outside storerooms and laboratories may lead to hazardous concentrations of vapors and gases being distributed throughout the building. 

The following guidelines should be observed when transporting chemicals outside the laboratory: 

1.  Elevators 

a.  Freight elevators shall be used where available to transport hazardous materials.  Under no circumstances are passenger elevators to be used for the transportation of hazardous materials if freight elevators are available. 

2.  Flammable Liquids 

a.  Flammable liquids shall be transported in rugged pressure-resistant safety cans. 

b.  Original containers of flammable liquids shall be placed in an outside container or acid-carrying bucket. 

c.  No more than 5 gallons of flammable liquids in glass containers shall be transported on the freight elevator unless the original shipping carton (box) is used and the materials are on an appropriate cart. 

3.  Corrosive or Oxidizing Materials 

a.  Original glass shipping containers holding liquids acids and bases must be placed in an outside container or acid-carrying bucket. 

b.  Incompatible chemicals, for example chromic acid (oxidizing acid) and ethyl acetate (flammable liquid), should not be transported on the same cart unless they are in original shipping cartons and physically separated. 

4.  Water Reactive Chemicals 

a.  Wherever possible, use the original outside shipping containers (packaging) when transporting water reactive chemicals. 

b.  Once opened, water reactive chemicals must be placed in a rigid outside container or acid carrying bucket for transporting. 

5.  Pyrophoric (spontaneously igniting) Substances 

a.  Whenever possible, the original outside shipping container (packaging) must be used to transport pyrophoric substances. 

b.  Once opened, pyrophoric substances must be placed in a rigid outside container or acid carrying bucket for transporting. 

6.  Acutely Toxic Compounds (See list Appendix B) 

a.  Whenever possible, the original outside shipping container (packaging) must be used to transport acutely toxic compounds. 

7. General 

a.  Chemical, substances and research materials must be clearly labeled with the correct chemical name when transported.  Legible hand-printed labels are acceptable; chemical formulas and structural formulas alone are not acceptable

b.  Carts used for chemical transport must have sides, on each shelf, that are high enough to retain the containers.  Cart wheels must be large enough to prevent the carts from being caught in floor cracks, and door and elevator thresholds. 

c.  Personnel transporting chemicals must (at a minimum) wear chemical resistant gloves and safety glasses. 

Questions concerning hazardous chemicals should be addressed to OHS at -3775.

 General Considerations for Chemical Storage 

Carefully read the label before storing a hazardous chemical.  The MSDS will also provide any special storage information and incompatibilities.

Do NOT store unsegregated chemicals in alphabetical order or incompatible chemicals in close proximity to each other. 

Chemicals should be separately stored by chemical class as follows: 


  • oxidizing solids

  • flammable solids

  • water reactive solids

  • all other solids


  • acid liquids

  • caustic liquids

  • oxidizing liquids

  • perchloric acid solutions

  • flammable or combustible liquids


  • toxic gases

  • flammable gases

  • oxidizing and inert gases

(Once separated into hazard classes, chemicals may be stored alphabetically). 

Use approved storage containers and safety cans for flammable liquids.  Use spill trays under containers of strong corrosive reagents.  Do not store liquids above eye level

Ensure that all containers are properly labeled.  For more information on chemical storage, contact your supervisor, Lead Instructor, Principal Investigator, or OHS. 

Chemical Stability

Stability refers to the susceptibility of the chemical to dangerous decomposition.  Ethers and olefins form peroxides on exposure to air and light.  Since these chemicals are packaged in an air atmosphere, peroxides can form even though the containers have not been opened.  Write the date received and date opened on all containers of ether 

Unless the manufacturer added an inhibitor, closed containers of ether should be discarded after 1 year. 

Open containers of ether should be discarded within 6 months of opening.  In the Science Careers labs, refilled ether cans should be so labeled. 

The label and MSDS will indicate if a chemical is unstable. 

The following are examples of materials that may form explosive peroxides






Diethyl ether

Diethylene glycol

Dimethyl ether


Divinyl acetylene

Ethyl ether


Isopropyl ether

Methyl acetylene


Vinylidene chloride

Vinyl ether

Ethylene glycol-dimethylether

For additional information on chemical stability, contact your Laboratory Supervisor, Lead Instructor or OHS. 

Shock Sensitive Chemicals

Shock sensitive” refers to the susceptibility of a chemical to rapidly decompose or explode when struck, vibrated or otherwise agitated.   

Some chemicals become increasingly shock sensitive with age.  Write the date received and date opened on all containers of shock sensitive chemicals.  Unless an inhibitor was added by the manufacturer, closed containers of shock sensitive materials should be discarded after one year.  Open containers of shock sensitive materials should be discarded within six months of opening.   Table 2 lists materials that can be shock sensitive.

Table 2

Shock Sensitive Chemicals*


acetylides of heavy metals

aluminum ophorite explosive



ammonium perchlorate

ammonium picrate

ammonium salt lattice

butyl tetryl

copper acetylide

cyanuric triazide






dinitrophenyl hydrazine

dipicryl sulfone


erythritol tetranitrates

explosive mixtures

fulminate of silver

fulminating gold

fulminating mercury

fulminating platinum


guanyl nitrosamino guanyltetrazene

guanyl nitrosamino guanylidene hydrazine






hydrazoic acid

lead azide

lead mannite

lead mononitro-resorcinate

lead salts

lead styphnate

magnesium ophorite

mannitol hexanitrate

mercury tartrate



nitrated carbohydrate

nitrated polyhydric alcohol

nitrogen trichloride

nitrogen tri-iodide





nitronium perchlorate

organic amine nitrates

organic nitramines

organic peroxides

picramic acid


picric acid

picryl chloride

picryl fluoride

potassium nitroaminotetrazole

silver acetylide

silver azide

silver styphnate

sodium amatol

sodium dinitro-ortho-cresolate

sodium nitrate-potassium explosive mixtures

sodium picramate






trinitrobenzoic acid







nitrates of ammonium, calcium, or urea

picric acid; many picrates!




*NOTE: This list is NOT all-inclusive.  Review the Material Safety Data Sheet for reactivity information concerning the chemicals you use.

Compressed Gases 

Carefully read the label before using or storing compressed gas. The MSDS will provide any special hazard information.  Always use the minimum size cylinder required to perform the work. 

Cylinders of compressed gases must be handled as high-energy sources.  When storing or moving a cylinder, have the cap securely in place to protect the stem.  Use suitable racks, straps, chains or stands to support cylinders.  Compressed gas cylinders pose a crush hazard to hands and feet. 

Do not expose cylinders to temperature extremes. 

Always use the correct regulator.  Do not use a regulator adapter.  Oil or grease on the high pressure side of an oxygen cylinder can cause an explosion.  Do not lubricate an oxygen regulator. 

Cylinders of toxic, flammable or reactive gases should be stored and used in a fume hood or with local ventilation. 

Never bleed a cylinder completely empty.  Leave a slight pressure to keep contaminants out.

 Always wear safety glasses when handling compressed gases.

 For more information, contact your Laboratory Supervisor, Lead Instructor, Principal Investigator, or OHS. 

Designated Areas

 All locations within the laboratory where acutely toxic, carcinogenic, or reproductive hazards are stored or handled should be demarcated with caution signs.  Storage areas must be segregated from other chemical storage.  This includes all fume hoods and bench tops where the acutely toxic, carcinogenic, or reproductive hazards are handled.

 The use of a designated area for handling and storage of these three chemical classes will minimize the exposure to laboratory workers and prevent accidental contact by untrained students, faculty, staff and administrators.

Flammable Gas Cylinders 

The storage of flammable gas cylinders is limited to two (2) type 1 (10" x 50") cylinders per 500 square feet of non-sprinklered laboratory space. 

Liquefied flammable gas containers should be limited to two (2) 9" x 30" cylinders per 500 square feet of non-sprinklered laboratory space or three (3) 9" x 30" cylinders per 500 square feet of sprinklered laboratory space.


Gary Lee
Director of Environmental Health
4601 College Blvd.
Farmington, NM  87401
(505) 566-3063 or (505) 566-3190