CHEMICAL STORAGE GUIDELINES

Chemical Storage

Proper storage is needed to minimize the hazards associated with accidentally mixing incompatible chemicals.

Do not sort and store chemicals alphabetically unless they have first been separated into hazard classes. Additional guidelines on storing chemicals according to their hazard classes are presented later in this section.

Observe the following general storage guidelines. (Note: Specific guidelines are presented later in this section):

• In general, chemicals should be separated according to the following categories:
• Solvents, which include flammable/combustible liquids and halogenated hydrocarbons (e.g., acetone, benzene, ethers, alcohols) Note:  Store glacial acetic acid as a flammable liquid
• Inorganic mineral acids (e.g., nitric, sulfuric, hydrochloric, and perchloric acids). 
• Bases (e.g., sodium hydroxide, ammonium hydroxide)
• Oxidizers
• Poisons
• Explosives or unstable reactives, such as picric acid.  Store separately outdoors in flammable storage cabinets
• Ensure that caps and lids on all chemical containers are tightly closed to prevent evaporation of contents.
• Store all hazardous liquid chemicals in drip trays that are chemically resistant. This is to minimize the impact and spread of a spill resulting from broken/leaking containers. 
• Photo trays provide good containment and are widely used at the Lab. Tray capacity must be 110% of the largest container or 10% of the aggregate volume of all containers, whichever is larger.
• Photo trays are available through several commercial sources including VWR Scientific.  The Laboratory has a “B2B contract” with VWR. These can be ordered online through  Procurement’s web page.
• An additional source of spill containment trays is Scientific Plastics.  This company provides trays in several depths, with width and length in 1” increments. These trays have been used at LBNL to contain entire shelves in storage cabinets.

• Install Plexiglas lips or use equivalent means to prevent materials from falling off storage shelves.
• Avoid storing chemicals on countertops or in fume hoods except for those being currently used.
• Label all containers (squeeze bottles and Nalgene bottles) to which hazardous materials are transferred with the identity of the substance and its hazards.
• Be aware that squeeze bottles and Nalgene bottles have varying resistances to different chemicals. The Nalgene website has a database for selecting chemically resistant wash bottles.
• Evaluate/test stored chemicals that can form peroxides for crystal formation, deterioration, and integrity (see Controls for Peroxide Forming Chemicals). A label has been developed to document evaluation and test results.

• Limit the amount of chemicals stored to the minimum required.
• Avoid exposure of chemicals to heat or direct sunlight. This may lead to the deterioration of storage containers as well as the degradation of the chemicals.
• Use approved corrosive storage cabinets (constructed of chemically resistant components) for storing acids and bases. Consult Control Procedures for Acids and Bases for additional information.

• Use flammable storage cabinets to store flammable liquids.  PUB 3000, Chapter 12, Fire Prevention and Protection and the Controls for Flammable and Combustible Liquids section contain more information on safe handling and storage of flammable and combustible materials.
• Chemical storage cabinets (such as corrosive and flammable storage cabinets) must be connected to the building's exhaust system. This applies to all cabinets installed during renovation or new construction. Most chemical storage cabinets are equipped with two bungs. Connect the bottom bung to the exhaust system with a metallic pipe (copper or steel flex hose - 2 inch diameter). The top bung is used to provide make up air to the cabinet and must be fitted with a flame arrester. Existing cabinets showing signs of interior corrosion or whose contents produce strong odors during storage will also be ventilated.
• Refrigerators used for storing chemicals, samples or media must be labeled with words to the effect as follows: “Caution – Do Not Store Food Or Beverages In This Refrigerator”. Refrigerators used for food storage in or near work areas (shops and labs) must be labeled with words to the effect as: “Notice – Food May Be Stored In this Refrigerator”. Labels may be fabricated by users provided they are legible and securely affixed to the refrigerator. Posting refrigerators used for food and beverage which are located in lunch rooms and office buildings, where there is no shop or lab type chemical usage do not require any posting.

The following guidelines are provided for the safe storage of hazardous materials in accordance with their hazard classes:

It is recommended that the EH&S Chemical Safety Web Page be consulted for additional guidance. This contains Material Safety Data Sheet and toxicological databases that can be accessed.  An EH&S Industrial Hygienist can also be consulted, if additional assistance is needed.

Acids

• Segregate acids from reactive metals such as sodium, potassium, magnesium, etc.
• Segregate oxidizing acids from organic acids, flammable and combustible materials.
• Segregate acids from chemicals which could generate toxic or flammable gases upon contact, such as sodium cyanide, iron sulfide, calcium carbide, etc.
• Segregate acids from bases.
• See Control Procedures for Acids and Bases.

Bases

• Segregate bases from acids, metals, explosives, organic peroxides and easily ignitable materials.
• See Control Procedures for Acids and Bases.

Solvents (Flammable and Halogenated Solvents)

• Store in approved safety cans or cabinets.
• Segregate from oxidizing acids and oxidizers.
• Keep away from any source of ignition:  heat, sparks, or open flames.
• See Control Procedures for Flammable and Combustible Liquids.

Oxidizers

• Store in a cool, dry place.
• Keep away from combustible and flammable materials.
• Keep away from reducing agents such as zinc, alkali metals, and formic acid.

Cyanides

• Segregate from acids and oxidizers.

Water Reactive Chemicals

• Store in a cool, dry place away from any water source.
• Make certain that a Class D fire extinguisher is available in case of fire.
• See Control Procedures for Water Reactive Chemicals.

Pyrophoric Substance

• (Materials which will react with the air to ignite when exposed, e.g., white phosphorus.)
• Store in a cool, dry place making provisions for an airtight seal.

Light Sensitive Chemicals

• Store in amber bottles in a cool, dry, dark place.

Peroxide Forming Chemicals

• Store in airtight containers in a dark, cool, and dry place.
• Label containers with receiving, opening, and disposal dates.
• Periodically test for the presence of peroxides.
• See Control Procedures for Peroxide Forming Compounds.

Toxic Chemicals

• Store according to the nature of the chemical, using appropriate security where necessary.

(From "Safe Chemical Storage:  A Pound of Prevention is Worth a Ton of Trouble" by David Pipitone and Donald Hedberg, Journal of Chemical Education, Volume 59, Number 5, May 1982 and "Fire Protection Guide on Hazardous Materials," NFPA, 1978.)

Know the properties of the chemicals used.

The chemical incompatibilities discussed below are by no means exhaustive.  As a result, it is important for laboratory personnel to thoroughly research the properties of the chemicals they are using.  Material Safety Data Sheets (MSDSs) have sections on chemical incompatibility.  The container's label should also provide storage guidelines.

Avoid mixing incompatible waste materials.

A number of serious laboratory accidents have occurred when people have poured incompatible waste materials into hazardous waste containers.  Use separate waste containers for each type of waste.  Consult an EH&S Waste Generator Specialist for guidance.

Store incompatible chemicals separately.

Common storage problems in laboratories can lead to mixing incompatible chemicals.  The most serious of these is the storage of acids (especially oxidizing acids) with flammable solvents.  Contact of a concentrated oxidizing acid with a flammable solvent would likely result in a fire or an explosion.  This is not an unlikely scenario in the event of an earthquake.  Storage of chemicals in alphabetical order on shelves often results in incompatible chemicals being stored together.  For example, alphabetical arrangement could result in hydrogen peroxide (a strong oxidizer) being stored next to hydrazine (a very strong reducer).

Chemical Storage - Incompatible Chemicals

Certain hazardous chemicals should not be mixed or stored with other chemicals because a severe reaction can take place or an extremely toxic reaction product can result. The label and MSDS will contain information on incompatibilities.

The following incompatibility matrix and table contains examples of incompatible chemicals:

Chemical Incompatibility Matrix

X = Not compatible – do not store together

(From Manufacturing Chemists' Association, Guide for Safety in the Chemical Laboratory, pp. 215-217, Van Nostrand Reinhold, 2nd Edition.)

Last updated 11/8/07

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