Chemical Storage: Categories, Hazards And Compatibilities

1. Labeling for Hazardous Material

1. Collect information on hazards from applicable sections of the safety data sheet (SDS) for the chemical. Some SDSs may even provide the NFPA 704 diamond symbol with hazard rating numbers filled in already.
2. If the SDS does not provide a NFPA diamond label for the chemical, the information may be obtained under the following sections of the SDS:
   • Health hazard information under Section 11
   • Flammability information under Section 9
   • Instability information under Section 10
   • Special information under Section 9, 10, 11
   Check other sections of the SDS for additional information.
3. Compare the SDS criteria with the current edition copy of NFPA 704 criteria shown in:
   • Table 5.2 Degrees of Health Hazards
   • Table 6.2 Degrees of Flammability Hazards
   • Table 7.2 Degrees of Instability Hazards
   • Table 8.2 Degrees of Special Hazards
4. Once the numbers for the degree of hazard associated with the criteria are determined, place in the correct quadrant of NFPA 704 placard.
5. The Hazard Communication Standard, 29 CFR 1910.1200 requires all manufacturers, importers, and distributers of hazardous materials to label chemicals with the following information: product identifier, signal word, hazard statement(s), precautionary statement(s) and pictogram(s), and name, address and telephone number of the material manufacturer, importer or distributer.
6. The product identifier can include the name and alternate names of the material, a code, such as the CAS number, and the product batch number.
7. The signal word is to indicate the level of the hazard and can only be 'warning' or 'danger'. 'Warning' means less severe, 'danger' means more severe.
8. A hazard statement describes the hazard of the material. Hazard statements are always written the same for a given hazard, for example, 'May cause allergy or asthma symptoms or breathing difficulties if inhaled'. The only acceptable alterations to hazard statements are if multiple hazard statements are combined to improve readability.
9. There are four types of precautionary statements: prevention, response, storage, and disposal. A prevention precautionary statement is aimed at minimizing risk, for example, 'handle under inert gas'. A response precautionary state is included in the case of a spill or exposure to the material, for example, 'take off immediately all contaminated clothing'. An example of a storage precautionary statement is 'protect from sunlight'. An example of a disposal precautionary statement is 'dispose of contents/container to comply with applicable local, national and international regulation.'

2. Segregate Incompatible Chemicals

1. Chemicals should always be segregated and stored according to their incompatible chemical and physical characteristics. Basic hazard groups include:
   1. Acids
   2. Bases
   3. Flammables
   4. Oxidizers
   5. Toxics
   6. Peroxide forming chemicals
   7. Pyrophoric forming substances
   8. Water reactive chemicals
   9. Explosives
2. Below are some common hazard groups to segregate:
   1. No acids with bases
   2. No bases with acids
   3. No acids or bases with flammables
   4. No oxidizers near compressed flammable gases
3. Incompatible chemicals must not be stored in close proximity to each other. In an emergency situation of a fire, earthquake or a spill, incompatible chemicals could mix and react to cause toxic fume production or an explosion.

3. Chemical Storage Method

1. Chemicals should be stored according to their incompatible chemical and physical characteristics. Alphabetical storage may be used within a compatible chemical group but never as a chemical storage plan for an entire inventory.
2. Chemicals must be stored in accordance to the manufacturer's directions or SDS instructions.
3. Liquid chemicals should not be stored over shoulder height to ensure easy access and handling and be stored in chemically resistant secondary containers in case there is a leak or spill.
4. Chemicals containers should be stored with closed and properly fitted caps.
5. Acids and bases should be stored separately and stored in acid cabinets or on protected shelves which are not metal in order to avoid corrosion
6. Flammable and combustible chemicals must be stored in approved flammable storage cabinets and kept away from any ignition source, oxidizers, or corrosives. Flammable storage cabinets should be properly vented into the building's dedicated vent system. Laboratory-grade flammable-safe refrigerators should be used when flammable chemicals require refrigeration. Do not store food or beverages in the laboratory refrigerator.
7. Toxic chemicals should be stored in a ventilated, cool, and dry area.
8. Peroxide forming chemicals must be dated upon delivery and opening, and must be disposed before the expected date of initial peroxide formation and be stored in a dark, cool, and dry area.
9. Air and water must be removed rigorously from containers of pyrophoric forming substances and should be stored away from flammables in a cool and dry area.
10. Explosives should be stored away from all other chemicals in a secure location and away from shock or friction.

4. Safety Data Sheets

Note: The purpose of the SDS is to provide an easy to understand, standardized document that informs the user of important information regarding the material. OSHA requires manufacturers, distributors, and importers to provide SDSs to end-users of hazardous materials (Hazard Communication Standard 29 CFR 1910.1200(g)). The SDS is a 16 section document containing details on properties, hazards, storage and transport, regulatory status, protective measures, and emergency procedures. The following is an outline of the 16 sections in an SDS.

1. Section 1: Identification: This section provides the name and alternate names of the material along with suggested uses, restrictions and contact information of the supplier.
2. Section 2: Hazard identification: Hazards associated with the material are identified in this section. Hazard symbols may be shown along with a description of the hazard.
3. Section 3: Composition/information on ingredients: For substances, this sections contains the chemical name, alternative names and identifiers, CAS number, impurities and additives. For mixtures, the same information for substances is provided for all components of the mixture. The percentage of each component is specified, except in the case of trade secrets. If chemical composition has been withheld due to trade secret, this must be stated. Toxicology data is provided for each hazardous substance in the material (lethal dose/lethal concentration, etc).
4. Section 4: First-aid measures: In the event of exposure (skin and eye contact, inhalation, or ingestion) to the material, this section states the first response procedures for untrained personnel. The effects, acute and delayed, are detailed.
5. Section 5: Fire-fighting measures: Appropriate and inappropriate extinguishing equipment, and recommended protective firefighting equipment is stated. Hazardous combustion products are listed.
6. Section 6: Accidental release measures: Procedures and methods for handling spills and leaks are outlined in this section. Personal precautions, emergency procedures containment methods and cleanup procedures are covered.
7. Section 7: Handling and storage: This section provides information on safe handling and storage of the material. Safe handling and storage conditions are outlined, including incompatibilities and hygiene practices.
8. Section 8: Exposure controls/personal protection: This section outlines exposure limits and engineering controls (e.g., ventilation system, glove box) and PPE (e.g., glove type, apron, face protection) that can be used to prevent exposure to the material.
9. Section 9: Physical and chemical properties: This section contains information regarding the physical and chemical properties of the material. The minimum information this section must require is state (gas, liquid, solid), color, odor, odor threshold, melting point, boiling point, density, vapor density, viscosity, vapor pressure, evaporation rate, pH, upper and lower flammability limits, upper and lower explosive limits, auto-ignition temperature, flash point, flammability, decomposition temperature, octanol-water partition coefficient, and solubility.
10. Section 10: Stability and reactivity: This section provides information on the reactivity of the material under specific conditions, incompatibilities and conditions that should be avoided.
11. Section 11: Toxicological information: This section contains information on the toxicology and health effects of the material. This includes effects and symptoms of acute and chronic exposure, routes of exposure (skin and eye contact, inhalation, or ingestion) and LD50/LC50 data. LD50/LC50 (lethal dose, 50%/lethal concentration, 50%) is the dose/concentration required to kill 50% of the exposed population in a set time frame.
12. Section 12: Ecological information: (non-mandatory) This section includes information on the environmental impact of the material. If available, data on aquatic and terrestrial organisms should be provided.
13. Section 13: Disposal considerations (non-mandatory): This section contains information on appropriate disposal of the material and items contaminated with the material, including appropriate containers and methods.
14. Section 14: Transport information (non-mandatory): This section outlines the transportation and shipping requirements of the material. Information includes the UN number, UN shipping name, transport hazard class, packing group number, relevant environmental hazards and any material specific instructions.
15. Section 15: Regulatory information (non-mandatory): This section details any regulatory information regarding the material or components of the material.
16. Section 16: Other information: This section notes when the SDS was last revised and any changes since the first revision.