PYROPHORIC CHEMICALS

The term “pyrophoric” describes chemicals that will ignite spontaneously in air at temperatures of 1300 F (540 C) or below. Pyrophoric chemicals react with oxygen, moisture in the air, or both. Failure to follow proper handling techniques can result in spontaneous combustion or explosion, leading to serious burns and other injuries.

Examples of Pyrophoric Compounds
*       Grignard reagents: RMgX
*       Metal alkyls and aryls: RLi, RNa, R3Al, R2Zn
*       Metal carbonyls: Ni(CO)4 (Nickel tetra carbonyl), Fe(CO)5 (Iron pentacarbonyl, CO2(CO)8 (Dicobalt octacarbonyl)
*       Alkali metals such as Na, K
*       Metal powders: Al, Co, Fe, Mg, Mn, Pd, Pt, Ti, Sn, Zn, Zr
*       Metal hydrides: NaH , LiAlH4
*       Nonmetal hydrides: B2H6 (diborane) and other boranes, PH3 (Phosphine), AsH3 (Arsine)
*       Nonmetal alkyls: R3B, R3P, R3As (materials containing boron, phosphorous, or arsenic)
*       Gases: Silane, Disilane, Dichlorosilane, Diborane, Borane, or Phosphine
*       Phosphorus (white)

*R= organic group; X=halogen

Observe the following general safe-handling techniques when handling pyrophoric chemicals, as well as specific instructions provided during training and by the applicable Material Safety Data Sheet. Special considerations for pyrophoric gasses are
·         Remove all excess and nonessential chemicals and equipment from the area where pyrophoric chemicals are in use. This will minimize the number and quantity of other chemicals and materials at risk should a fire occur. Combustible materials, including paper products, should not be allowed to come in contact with any pyrophoric reagent at any time.

·         Use and store minimal amounts of pyrophoric chemicals. Do not store pyrophoric chemicals with flammable materials or in a flammable-liquids storage cabinet. Store as recommended in the Material Safety Data Sheet, for example, in a dry, inert atmosphere such as a nitrogen-filled desiccator or glove box.

·         If packaged in a specially designed shipping/storage/dispensing container, ensure that the integrity of the container is maintained. Some reactive metals are packaged, shipped, and stored under oil or kerosene. Ensure that sufficient protective solvent remains in the container while the material is stored.

·         Conduct operations in a manner to prevent exposure to the atmosphere. Several techniques, depending on the physical state and quantity used, are available. These techniques range from use of gas-tight syringes to glove boxes. Many pyrophoric chemicals release noxious or flammable gases and should be handled in an exhaust hood. In addition some pyrophoric materials are stored under kerosene (or other flammable solvents); therefore the use of a fume hood is required to prevent the release of flammable vapors into the laboratory. Glove boxes may be used if inert or dry atmospheres are required.

·         Never return excess chemicals to the original container. Small amounts of impurities introduced into the container may cause a fire or explosion.

·         Class D fire extinguishers, soda ash, or dry sand can be used to smother and extinguish small fires.

·         DO NOT use carbon dioxide or water fire extinguishers as these types of extinguishers can actually enhance the combustion of some pyrophoric compounds.

·         As with all operations, appropriate personal protective equipment is a must when handling hazardous chemicals.
-          Apron/ Lab coat or other protective outer garment, along with long pants and close toed shoes.
-          At a minimum, eye protection in the form of safety glasses with side shields. If there is a splash hazard, upgrade eye protection to goggles or goggles and face shields.
-          Protective gloves. Advice on chemical resistant glove selection is available in the applicable MSDS. Glove guides and other chemical safety information

-          Contact EHS for guidance on safe disposal of pyrophoric chemicals.

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