Appendix K

• Incompatible chemicals should be separated. Incompatibility information and the DOT hazard class is found on SDSs (Incompatibility or Reactivity section, Transportation Information section), container labels, and in other reference sources such as this NOAA site (excellent database) Reactivity worksheet.
• The potential hazards of storing incompatible chemicals together include:
  • Generation of heat.
  • Possible fires and explosion.
  • Generation of toxic and/or flammable gases and vapors.
  • Formation of toxic compounds.
  • Formation of shock and/or friction sensitive compounds.
  • Violent polymerization.

A number of segregation schemes are found in the literature. When choosing a segregation scheme keep in mind that chemicals do not always fall neatly into one hazard class. Chemicals may display both physical and health hazards such as flammable liquid, corrosive or flammable liquid, poison.

• When a chemical fits in more than one hazard category, store the chemical according to the highest risk based on severity of consequences and likelihood.
  • Fire is generally considered to be the highest risk category therefore flammability/combustibility should be used as the foremost storage criteria.
• Use the various literature resources and the SDSs for determining the hazard characteristics of a compound.
• When you are making decisions on how to segregate, consider the:
  • Physical hazards of the chemical.
  • Health hazards of the chemical.
  • Chemical form (solid, liquid or gas).
  • Concentration of the chemical.
• Separate liquids from solids :
  • • Separate all the chemicals into compatible groups. The separations, either by distance or physical barriers, should be enough to prevent the mixing of two incompatibles if a container is dropped and breaks a second container.
    • The following groups should be separated:
      • Chemicals showing hazards such as flammability, reproductive toxicity, or suspect and confirmed carcinogens :
        • Inorganic and organic flammables are separated. In addition, organic flammables are further separated into two classes based on compatibility.
        • Highly toxic and carcinogenic chemicals are stored in safety storage cabinets and carried back and forth from the storage cabinet to the hood in an unbreakable outer container.
      • Acids and bases
        • Acids should be further separated into inorganic acids (hydrochloric, sulfuric) and organic acids (picric, acetic).
        • Concentrated acids should be stored in an acid storage cabinet.
        • Separate acids from active metals (such as sodium, magnesium, and potassium) and chemicals that generate toxic gases on contact with acids (such as inorganic cyanides and sulfides). Picric Acid can form explosive salts with many metals, or by itself when dry.
        • Store oxidizing acids (such as nitric acid (store separately), perchloric, and chromic acid) away from organic acids, and organic solvents.
        • Concentrated Perchloric acid should be stored in glass or plastic (polyethylene or polypropylene), keep secondary containers away from all organic and combustible materials (such as wooden shelves and paper).
        • Glacial acetic acid has a flash point of approximately 103 ºF (39 ºC) and is best stored as a flammable liquid.
        • Store Hydrofluoric Acid in tightly closed polyethylene containers NOT glass containers. See Appendix Q for hydrofluoric acid.
      • Oxidizing agents from reducing agents
      • Potentially explosive materials
      • Water reactive materials
      • Pyrophoric chemicals
      • Peroxide forming materials - these must be properly managed and disposed of within recommended time periods (Appendix J)
      • Materials which can react with themselves (Polymerization for example)
      • Incompatible chemicals NOAA site excellent database Reactivity worksheet
      • Other chemicals can generally be grouped together (but compatibility must be considered).
      • Segregate compressed gases as follows:
        • Toxic gases
        • Flammable gases
        • Oxidizing and inert gases
    • Use secondary containment (trays, bins, or plastic bags) to segregate chemical hazard classes (such as acids and bases) within the same cabinet or shelf unit.
      • However, even when using secondary containment
        • never store oxidizers and flammables in the same cabinet or shelf unit,
        • never store compounds such as inorganic cyanides and acids in the same cabinet or shelf
    • Once chemicals have been separated, train and ensure everyone in the lab knows the process and what system is being used. (Training form Appendix F)
    • Identify where chemicals in each hazard class will be stored by labeling cabinets with signs, or hazard class labels. These can be purchased from a safety supply company, you can create your own, or download labels from the EH&S Signs and Labels web page.
    • The basic DOT hazard classes for transportation and hazard class numbers are:

  DOT Hazard Class Number	Hazard Class
  Class 1	Explosives
  Class 2	Compressed gases
  Class 3	Flammable liquids
  Class 4	Flammable solids
  Class 5	Oxidizers
  Class 6	Poisons
  Class 7	Radioactive materials
  Class 8	Corrosives
  Class 9	Miscellaneous, store with Class 6

  • The benefits of chemical segregation by hazard class include:
    • Safer chemical storage.
    • Understanding the hazards a chemical exhibits will increase your knowledge about the chemical.
    • Identifying potentially explosive chemicals.
    • Identifying multiple containers of the same chemical.
  • A suggested compatible grouping and chemical storage segregation scheme is provided below. This scheme is not the only method of arranging these chemicals and is only offered as a convenience not as an endorsement by AU.

  The Flinn Chemical & Biological Catalog Reference Manual suggests organic and inorganic groupings which are further sorted into a list of compatible families. This list is not all inclusive and is only intended to cover the chemicals found in an average laboratory.

  	Inorganic		Organic
  1	Metals, Hydrides	1	Acids, Amino Acids, Anhydrides, Peracids
  2	Acetates, Halides, Iodides, Sulfates, Sulfites, Thiosulfates, Phosphates, Halogens, Oxalates, Phthalates, Oleates	2	Alcohols, Glycols, Sugars, Amines, Amides, Imines, Imides
  3	Amides, Nitrates (except Ammonium Nitrate), Nitrites, Azides	3	Hydrocarbons, Esters, Aldehydes, Oils
  4	Hydroxides, Oxides, Silicates, Carbonates, Carbon	4	Ethers, Ketones, Ketenes, Halogenated Hydrocarbons, Ethylene Oxide
  5	Sulfides, Selenides, Phosphides, Carbides, Nitrides	5	Epoxy Compounds, Isocyanates
  6	Chlorates, Bromates, Iodates, Chlorites, Hypochlorites, Perchlorates, Perchloric Acid, Peroxides, Hydrogen Peroxide	6	Peroxides, Hydroperoxides, Azides
  7	Arsenates, Cyanides, Cyanates	7	Sulfides, Polysulfides, Sulfoxides, Nitriles
  8	Borates, Chromates, Manganates, Permanganates, Molybdates, Vanadates	8	Phenols, Cresols
  9	Acids (except Nitric Acid which is isolated and stored by itself)	9	Dyes, Stains, Indicators
  10	Sulfur, Phosphorus, Arsenic, Phosphorus Pentoxide	10	Organic miscellaneous
  11	Inorganic miscellaneous

  Suggested Shelf Storage Patterns

  boxes depict cabinets with/and/or shelves

  Poisons Cabinet - locked

  store severe poisons here

   

  Inorganic Chemical Storage
  Inorganic #10 Sulfur, Phosphorus, Arsenic, Phosphorus Pentoxide	Inorganic #7 Arsenates, Cyanides, Cyanates
  Inorganic #2 Halides, Sulfates, Sulfites, Thiosulfates, Phosphates, Halogens, Acetates	Inorganic #5 Sulfides, Selenides, Phosphides, Carbides, Nitrides
  Inorganic #3 Amides, Nitrates (except Ammonium Nitrate), Nitrites, Azides Isolate Amnonium Nitrate From All Other Substances	Inorganic #8 Borates, Chromates, Manganates, Permanganates	Acid Cabinet Inorganic #9 Acids except Nitric unless your acid cabinet provides a separate compartment for Nitric Acid
  Inorganic #1 Metals, Hydrides Store Away from Water Store Flammable Solids in Flammables Cabinet	Inorganic #6 Chlorates, Bromates, Iodates, Chlorites, Hypochlorites, Perchlorates, Perchloric Acid, Peroxides, Hydrogen Peroxide
  Inorganic #4 Hydroxides, Oxides, Silicates, Carbonates, Carbon	Miscellaneous

  Organic Chemical Storage
  Organic #2 Alcohols, Glycols, Sugars, Amines, Amides, Imines, Imides Store Flammables in a Dedicated Cabinet	Organic #8 Phenols, Cresols
  Organic #3 Hydrocarbons, Esters, Aldehydes, Oils Store Flammables in a Dedicated Cabinet	Organic #6 Peroxides, Hydroperoxides, Azides
  Organic #4 Ethers, Ketones, Ketenes, Halogenated Hydrocarbons, Ethylene Oxide Store Flammables in a Dedicated Cabinet	Organic #1 Acids, Amino Acids, Anhydrides, Peracids Store Certain Organic Acids in Acid Cabinet	Flammable Cabinet Organic #2 Alcohols, Glycols, etc. Organic #3 Hydrocarbons, etc. Organic #4 Ethers, Ketones, etc. Organic #9 Alcohol-based Indicators, etc.
  Organic #5 Epoxy Compounds, Isocyanates	Organic #9 Dyes, Stains, Indicators Store Alcohol-Based Solutions in Flammables Cabinet
  Organic #7 Sulfides, Polysulfides, Sulfoxides, Nitriles	Miscellaneous