HANDLING AND STORAGE OF CHEMICALS AND SOLVENTS

This section provides general guidance for safely managing hazardous chemicals in the laboratory. Additional information is provided during laboratory chemical safety training.


Chemical Ordering

  • Cyanide and Nitrile are among the most toxic substances encountered in the Chemical laboratory. The compounds are toxic if inhaled, ingested, or absorbed through the skin. HCN readily occupies the oxygen binding site on the hemoglobin molecules in red blood cells, causing death by oxygen deprivation. You must obtain lab certification from the Department Chair before using Cyanide or Nitrile.

 

  • UVA limits individual chemical containers to a maximum capacity of 4 liters or 1 gallon. The Virginia State Fire Marshal does not permit the storage and use of flammable liquids in 5 -gallon cans or larger.

 

  • Where a choice is available, order chemicals in safety-coated or shatter-resistant containers, especially corrosive and reactive materials.

 

  • Ensure your laboratory has an appropriate place to store and use new chemicals. For example, using toxic volatile liquids requires a chemical fume hood, while compressed toxic or corrosive gases generally require a dedicated ventilated gas cabinet. Consult EHS if you have questions about the safety infrastructure needed for a new chemical.

 

  • Ensure all chemicals, especially flammables, are purchased in the smallest quantities needed

and inventories are maintained at levels reasonably needed to perform work.

 

Chemical Transport

  • When transporting chemical containers outside of the laboratory or between work areas, use a secondary container such as a chemical bottle tote, covered bucket, or a tray. Be sure to secure the load or use a cart with raised edges. Wheels should be large enough to roll over uneven floor surfaces and elevator door gaps.

 

  • Use extra care when transporting chemicals in elevators since these locations have limited ventilation and are difficult to exit quickly in the event of a spill. Avoid transporting cryogen tanks and liquid nitrogen tanks in passenger elevators. Use service elevators when available, and do not ride with the tank in the elevator. Use a “buddy system” to intercept passengers if you must transport up or down several floors.

 

  • Contact EHS for assistance if you need to: Transport large quantities of chemicals elsewhere indoors, move or transport chemicals outdoors, or ship any chemicals or research specimens off-Grounds.

 

Chemical Storage & Handling

  • Segregate and store chemicals by their hazards using a classification system.

           o See Appendix E for guidelines.

 

  • Keep flammable liquids in storage devices listed or approved by the National Fire Protection Association. Flammable storage cabinets must have self-closing doors and be prominently posted. Cabinet vents must be capped closed or, if connected to building exhaust, provided with a flame arrestor.

 

  • Refrigerators and freezers used to store flammable liquids below room temperature must also be listed or approved for such use – never store flammable materials in an ordinary refrigerator or freezer.

 

  • Date-labeling is recommended for all chemicals, but especially for unstable materials and those that can form reactive / explosive secondary products over time such as peroxides and shock- sensitive salts, e.g., ethers, other peroxide-forming chemicals, picric acid, perchloric acid.

 

  • Periodically inspect chemical storage areas for expired materials and for any containers with damages such as bulging or deformation exteriors, broken caps or lids, discoloration, or unexpected precipitates or crusts. Consult EHS for assistance before repackaging.

 

  • A fume hood or other approved ventilation/exhaust system should be utilized whenever flammable solvents or toxic gases are used. Do not operate the fume hood with the sash above the indicated level.

 

  • The best ventilating efficiency is attained with the hood sash closed. Keeping all items at least 6 inches behind the sash line and minimizing the quantity of equipment within the hood area will greatly improve its exhaust effect.

 

  • The operating condition of a hood should be determined before the hood is used. Fume hoods are inspected and certified annually by EHS. They will affix a label on the fume hood indicating the operability of the system and the maximum acceptable elevation of the hood sash. If your fume hood has not been inspected in more than one year, please call EH&S.

 

  • Perchloric Acid - The use of perchloric acid can result in the accumulation of explosive perchlorate crystals on chemical fume hood surfaces and inside ductwork. Work that involves heating or evaporating concentrated perchloric acid must be performed in a special Perchloric Acid Fume Hood. These devices have self-contained water rinsing and wash- down features to minimize the formation and accumulation of reactive crystals. These are available in select labs in Jesser and Wilsdorf Halls.

 

  • All chemicals must be correctly and clearly labeled and kept in capped containers. Parafilm and aluminum foil are not acceptable for long-term storage of chemicals. Screw caps should be used whenever possible Post warning signs when unusual hazards, such as radiation, flammable materials, biological hazards, or other special problems exist. It is recommended that you place your initials and date on the label of any chemical container.

 

  • Chemical splash goggles (or face shields) and rubber gloves should be worn when concentrated acids are poured. Such equipment must also be worn when any highly reactive or toxic chemicals are handled, such as elemental sodium or cyanide.

 

  • All chemicals must be organized and stored on shelves or in cabinets where they will not be knocked over. One way to organize chemicals is to store organics by number of Carbon atoms and keep them separate from inorganics, which should be stored in alphabetical order. Upon receipt, date and initial the label so that the age of the stock can be determined.

 

  • All chemicals in the laboratory must be labeled with permanent labels. The label should indicate the full chemical name and the primary hazard associated with the substance (e.g., flammable, toxic). Do not use abbreviations. Include your initials and date.

 

  • Discarding containers- UNBROKEN chemical reagent, salt, and solvent bottles can be discarded in trash bins once they are THOROUGHLY RINSED. If a chemical label is present, it should be removed or defaced.

 

  • Only "non-hazardous materials," may be poured into a sink. For all other materials follow the waste disposal guidelines in SECTION X). Concentrated acids and bases can be removed by the Environmental Health and Safety Office. Contact the EHS Office If you are unsure.

 

  • Dichromate in Sulfuric acid and other strong acid or oxidizer cleaning solutions should not be used for general cleaning purposes. Due to liberation of extremely toxic chromyl chlorides, Dichromate/Sulfuric acid is approved for use only in fume hoods.

 

  • Concentrated acids and bases should be stored in containment trays, separated from all other chemicals. They should not be stored on high shelves. ACIDS AND BASES SHOULD BE STORED IN SEPARATE CABINETS.

 

  • Peroxides, hydroperoxides, and peroxyesters - these compounds are all active oxygen- containing materials which can decompose generating oxygen or oxidizing agents. These materials are chemically unstable to varying degrees. Many organic compounds, including the following types, are known to form extremely dangerous peroxides.
    • Aldehydes and Ketones, Ethers, especially cyclic ethers such as THF.
    • Compounds containing benzylic hydrogen atoms, e.g. cumene.
    • Compounds containing the allylene (CH2=CHCH2R structure).
    • Vinyl and vinylidene compounds, e.g., vinyl acetate and vinylidene chloride.
    • Examples of common materials which form dangerous peroxides upon long exposure to air are: Cyclohexene, Cyclooctene, Decalin, p-Dioxane, Ethyl ether, Isopropyl ether, Tetrahydrofuran (THF) and Tetralin.

 

  • Disposal of Peroxides - Do not mix with other chemicals for disposal – keep in a separate contained properly labeled for disposal by EHS.

 

·Special precautions are needed for other especially hazardous chemicals:

  • Picric acid, which is highly shock sensitive,
  • Ethers, can form highly unstable peroxides, should be discarded after 6 months,
  • Triethyl aluminum, which is highly pyrophoric,
  • Lithium aluminum hydride, which is highly water reactive,
  • Piranha solution, which is a strong corrosive and oxidizer.

 

  • Flammable solvents-Properties of flammable liquids:
  • Flash Point: Temperature at which the vapor pressure is sufficient to form an ignitable mixture with the air.
  • Ignition Temperature: Minimum temperature required to cause self-sustained combustion.

 

•Classification of flammable liquids:

Class IA Liquids: flash point below 73oF (23 C) and boiling point below 100oF (38 C). Class IB Liquids: flash point below 73oF (23 C) and boiling point at or above 100oF (38 C). Class IC Liquids: flash point between 73oF (23 C) and 100 oF (38 C).

Class II Liquids: flash point between 100oF (38 C) and 140 oF (60 C). Class IIIA Liquids: flash point between 140oF (60 C) and 200 oF (93 C). Class IIIB Liquids: flash point above 200oF (93 C).

 

The maximum allowable size of containers for flammable liquids is as follows:

Glass/Plastic

  • Class IA              1 pt
  • Class IB              1 gal
  • Class IC              1 gal
  • Class II                1 gal
  • Class III              1 gal

Tinplate can

  • Class IA              1 gal
  • Class IB              5 gal
  • Class IC              5 gal
  • Class II                5 gal
  • Class III              5 gal

Safety Cans

  • Class IA              2 gal
  • Class IB              5 gal
  • Class IC              5 gal
  • Class II                5 gal
  • Class III              5 gal

The toxicity of common solvents should be recognized. It is best to consider every chemical toxic and to protect yourself accordingly. Examples include:

  • Certain aromatic hydrocarbons
  • Esters of organic acids
  • Ethylene glycol, glycol esters and glycol ethers
  • Halogenated hydrocarbons
  • Lower alcohols - methanol, ethanol, etc.
  • Nitrogenous compounds such as amine
  • A list of some common solvents is given in the following table

 

Name (Class)

Flash pt. F (C)

Boiling Pt. F (C)

 

Acetone (IB)

 

0 (-18)

 

133 (56)

Acetonitrile (IB)

42 (6)

179 (82)

Benzene (IB)

12 (-11)

176 (80)

Butanol (IC)

84 (29)

243 (117)

Carbon disulfide (IB)

-22 (-30)

115 (46)

Cyclohexane (IB)

0 (-18)

179 (82)

p-Dioxane (IB)

55 (13)

214 (101)

Ethanol (IB)

55 (13)

173 (78)

Diethylether (IA)

-49 (-45)

95 (35)

Heptane (IB)

25 (-4)

209 (98)

Hexane (IB)

-7 (-22)

156 (69)

Methanol (IB)

53 (11)

147 (64)

M.E.K. (IB)           

16 (-9)

176 (80)

Octane (IB)

56 (13)

258 (126)

n-Pentane (IA)

-57 (-49)

97 (36)

2-Propanol (IB)

53 (12)

181 (83)

THF (IB)

6 (-14)

151 (66)

Toluene (IB)

40 (4)

231 (111)

p-Xylene (IC)

81 (27)

281 (138)

 

Additional Requirements for Particularly Hazardous Substances

The OSHA Lab Safety Standard specifically mandates that labs maintain an inventory and develop additional precautions for handling “Particularly Hazardous Substances”, which they define as Select Carcinogens, Reproductive Toxins and Acute Toxins. If you are unsure if a chemical fall into one of these categories, check the SDS, or contact EHS.

When working with Particularly Hazardous Substances or other high hazard or regulated chemicals, laboratories are advised to:

  • Maintain an inventory of these chemicals and restrict access to authorized persons.
  • Seek formal review and approval from laboratory supervisory personnel for new work or scale-ups. Conduct a “dry run” as appropriate and revise procedures accordingly.
  • Establish one or more Designated Areas for the handling and use of these chemicals. The Designated Area may be as small as a portion of a laboratory bench, the interior of a chemical fume hood, or as large as the entire laboratory.
  • Post Designated Areas with labels or signage as follows:

section 7 handling clean.JPG

  • Providing containment approrpiate to the chemical and task such as an absorbent bench coating or covering, non-absorbent tray, or a device with inherent spill containment such as the interior of a chemical fume hood.

 

  • Weigh dry powders in a HEPA filtered weigh station enclosure or inside a chemical fume hood with a shield to minimize air currents. Preparing concentrated stock solutions is preferred to repeat dry powder handling if the resulting solution is stable and has good storage characteristics. Alternatively, where possible, purchase highly toxic dry powder reagents in pre-weighed vials with rubber septa to eliminate open air powder handling.

 

  • Perform any inactivation, neutralization, or other step(s) designed to render a hazardous chemical into a less or non-hazardous state before completing the experimental procedure. Review these protocols in advance with EHS.