Requirements and Work Practices

The Chemical Hygiene and Safety Plan (ES&H Manual Chapter 45) Requires:

• • Inorganic (mineral) acids must be stored in a corrosive or acid storage cabinet with corrosion-resistant interior and hardware and self-closing, self-latching doors.

  • All flammable and combustible liquids must be stored in a flammable storage cabinet with self-closing, self-latching doors; or in a flammable-approved or explosion-proof refrigerator; or in an approved flammable liquid safety can.

    • Note: Small quantities of flammable and combustible liquids may be kept in tightly closed plastic bottles outside of these storage options when they are being used for ongoing processes or experiments and are kept in secondary containment. For example, it is allowed to keep a small squeeze bottle of ethanol in a tray near an instrument for daily cleaning of the optics.

  • Flammable and combustible liquids may not be stored in standard refrigerators due to the risk of flammable vapor explosion initiated by the exposed electrical systems in normal refrigerators.

  • Hazardous materials may not be stored under sinks (with the exception of commercially available cleaners such as glass cleaner and bleach).

  • Note: Commercial cleaners containing ammonia must be segregated from any product containing sodium hypochlorite bleach. The mixture of ammonia with sodium hypochlorite produces chloramine gases, which are highly toxic.

  • All liquid hazardous materials must be in secondary containment trays to contain spills and leaks. This includes those stored within cabinets.

  • Incompatible materials must be segregated.

The Chemical Hygiene and Safety Plan requires the following materials to be segregated:

• • Acids from Bases

  • Acids from Reactive Metals (Na, Mg, K, etc.)

  • Oxidizing Acids (HNO₃, HClO₄, etc.) from Organic Acids (acetic acid, formic acid, oleic acid, etc.)

  • Oxidizing Acids from Flammable and Combustible Materials

  • Acids (either mineral acids or organic acids) from materials that can generate toxic or flammable gases on contact with acids (cyanide salts, sodium azide, organic cyanides, metal sulfides, thiols, metal carbides, etc.)

  • Nitric acid from all other acids.

  • Flammable and Combustible Liquids from Oxidizing Acids and Oxidizers

  • Alkali Metals from Halogenated Hydrocarbons

  • Pyrophoric Materials from Flammable and Combustible Liquids

Other than the requirements listed above, the exact implementation of segregation is left to the professional judgement of the chemical owner. This site provides some best practices that chemical owners may use to improve their chemical storage segregation. Please see the Chemical Hygiene and Safety Plan for more information on LBNL policy and work processes, or contact chemsafety@lbl.gov.

There are other methods of chemical segregation, such as the Storage Groups system presented in Prudent Practices in the Laboratory by the National Research Council. In addition, staff can review a summary of the storage groups as well as a table of examples for the storage groups.