In this plan there are nine storage groups. Seven of these groups cover storage of liquids
because of the wide variety of hazards posed by these chemicals. Specific instructions must be
followed for metal hydrides (Group VIII) and certain individual compounds, but otherwise, dry
solids are in Group IX.
Many liquid chemicals pose hazards that correspond to more than one storage group. These
chemicals should be stored in the lowest group number.
Group I Flammable Liquids
Group II Poisons - volatile
Group III Acids - Oxidizing
Group IV Acids - Organic and Mineral
Group V Bases - Liquid
Group VI Oxidizer - Liquid
Group VII Poisons - Non-volatile
Group VIII Reactives
Group IX Solids
Group I: Flammable Liquids
Includes liquids with flashpoints < 55 °C. Examples: all alcohols,
acetone,acetaldehyde,acetonitrile, amyl acetate, benzene, cyclohexane,
dimethyldichlorosilane, dioxane, ether, ethyl acetate, histoclad, hexane, hydrazine, methyl
butane, picolene, piperidine, propanol, pyridine, scintillation liquids, all silanes, tetrahydrofuran,
toluene, triethylamine, xylene
Primary Storage Concern: To protect from ignition
1. Flammable cabinet
2. Refrigerator: for containers less than 1 liter.
Compatible Storage Groups: Volatile poisons may be in the same compartment of the flammable
cabinet as flammables if bases are not present.
Group II: Volatile Poisons
Includes poisons, toxics and known and suspected carcinogens with strong odor or
evaporation rate greater than 1 (butyl acetate = 1): Examples: carbon tetrachloride, chloroform,
dimethylformamide, dimethyl sulfate, formamide, formal dehyde, halothane, mercaptoethanol,
methylene chloride, phenol.
Primary Storage Concern: To prevent inhalation exposures.
1. Flammable cabinet
2. Refrigerator: for containers less than 1 liter.
Compatible Storage Groups: Volatile poisons may be in the same compartment of the
flammable cabinet as flammable if bases are not present.
Group III: Oxidizing Acids
All oxidizing acids are highly reactive with most substances and each other. Examples: nitric,
sulfuric, perchloric, phosphoric acids, and chromic acids.
Primary Storage Concern: Preventing contact and reaction with each other and other
substances and corrosive action on surfaces.
1. Safety Cabinet. Each oxidizing acid must be double-contained, i.e., the primary container
must be kept inside canister, tray or tub.
Compatible Storage Groups:
Oxidizing acids must be double-contained and should be segregated in their own compartment
in a safety cabinet. When quantities are small (e.g., 1 or 2 bottles) they do not warrant a
separate compartment. Small quantities may be double-contained and stored with Group 4
Organic and Mineral Acids. Store oxidizing acids on bottom shelf below Group 4.
Group IV: Organic and Mineral Acids
Examples: acetic, butyric, formic, glacial acetic, hydrochloric, isobutyric, mercaptoproprionic,
proprionic, trifluoroacetic acids.
Primary Storage Concern: To prevent contact and reaction with bases and oxidizing acids and
corrosive action on surfaces.
1. Safety cabinet.
Compatible Storage Groups: Small amount of double-contained oxidizing acids can be stored
in the same compartment with organic acids if the oxidizing acids are stored on the bottom
Exceptions: acetic anhydride and trichloroacetic anhydride are corrosive. These acids are very
reactive with other acids and should not be stored in this group. It is better to store these with
organic compounds as in Group 7 Non-volatile Liquid Poisons.
Group V: Liquid Bases
Examples: sodium hydroxide, ammonium hydroxide, calcium hydroxide, glutaraldehyde
Primary Storage Concern: Preventing contact and reaction with acids.
1. Safety cabinet;
2. In tubs or trays in normal cabinet.
Compatible Storage Groups: Liquid bases may be stored with flammables in the flammable
cabinet if volatile poisons are not also stored there.
Group VI: Oxidizing Liquids
Oxidizing liquids react with everything potentially causing explosions or corrosion of surfaces.
Examples: ammonium persulfate, hydrogen peroxide (if greater than or equal to 30%)
Primary Storage Concern: To isolate from other materials.
1. Total quantities exceeding 3 liters should be kept in a cabinet housing no other chemicals.
2. Smaller quantities must be double-contained if kept near other chemicals, e.g., in a
Compatible Storage Groups: None
Group VII: Non-Volatile Liquid Poisons
Includes highly toxic (LD50 oral rat < 50 mg/kg) and toxic chemicals (LD50 oral rat < 500
mg/kg), known carcinogens, suspected carcinogens and mutagens Examples: acrylamide
solutions; diethylpyrocarbonate; diisopropyl fluorophosphate; uncured epoxy resins; ethidium
Primary Storage Concern: To prevent contact and reaction with other substances.
Cabinet or refrigerator (i.e., must be enclosed)
Do not store on open shelves in the lab or cold room.
Liquid poisons in containers larger than 1 liter must be stored below bench level on shelves
closest to the floor. Smaller container of liquid poison can be stored above bench level only if
behind sliding (non-swinging) doors.
Compatible Storage Groups: Non-hazardous liquids (e.g., buffer solutions).
Exceptions: Anhydrides, e.g., acetic and trichloroacetic, are organic acids, however it is
better to store with this group than with Group 4 Organic Acids, since they are highly reactive
with other organic or mineral acids.
Group VIII: Reactives Metal Hydrides and Pyrophorics
Most metal hydrides react violently with water, some ignite spontaneously in air
(pyrophoric).Examples of metal hydrides, are sodium borohydride, calcium hydride, lithium
aluminum hydride. Other pyrophorics are boron, diborane, dichloroborane, 2-Furaldehyde,
diethyl aluminum chloride, lithium, white or yellow phosphorus and trimethyl aluminum. Other
water reactives include aluminum chloride-anhydrous, calcium carbide, acetyl chloride,
chlorosulonic acid, sodium, potassium, phosphorous pentachloride, calcium, aluminum
tribromide, calcium oxide, and acid anhydrides.
Primary Storage Concern: To prevent contact and reaction with liquids and, in some cases,
1. Secure, water-proof double-containment according to label instructions.
2. Isolation from other storage groups.
Compatible Storage Groups: If securely double-contained to prevent contact with water
and/or air, metal hydrides may be stored in the same area as Group 9 Dry Solids.
Group IX: Dry Solids
Includes all powders, hazardous and non-hazardous. Examples: benzidine, cyanogen bromide,
ethylmaleimide, oxalic acid, potassium cyanide, sodium cyanide
Primary Storage Concern: To prevent contact and potential reaction with liquids.
1. Cabinets are recommended, but if not available, open shelves are acceptable.
2. Store above liquids.
3. Warning labels on highly toxic powders should be inspected and highlighted or
amended if they do not cause the containers to stand out against less toxic substances
in this group.
4. It is recommended that the most hazardous substances in this group be segregated.
5. It is particularly important to keep liquid poisons below cyanide-or sulfide-containing
poisons (solids). A spill of aqueous liquid onto cyanide - or sulfide - containing poisons
would cause a reaction that would release poisonous gas.
Compatible Storage Groups: Metal hydrides, if properly double-contained may be
stored in the same area.
Exceptions: Solid picric or picricsulfonic acid can be stored with this group, but should
be checked regularly for dryness. When completely dry, picric acid is explosive and
may detonate upon shock or friction. Picric acid in contact with some metals may form
explosive metal picrates. Use non-metal caps.