Pyrophoric Reagents Handling in Research Labs

Purpose and Applicability

Pyrophoric reagents react with air or moisture in air; this reaction can readily lead to fire. This generic chemical safety guidance describes basic prudent safety practice for handling pyrophoric reagents in research labs. The principal investigator (PI) or the lab manager is responsible for developing and implementing standard operating procedures (SOPs) for the purchase, storage, and safe handling of pyrophoric reagents that are specific to the PI’s research.

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Hazards

Even small amounts of pyrophoric chemicals can initiate a lab fire. Examples of pyrophoric reagents and hazards associated with these reagents are shown in the table below. A more extensive list of pyrophoric compounds can be found in Bretherick’s Handbook of Reactive Chemical Hazards (see External Links below).

Hazardous properties associated with pyrophoric reagents include: a) flammability, b) corrosivity, c) peroxide formation, d) teratogenicity, and e) target organ effects such as liver, kidneys, and central nervous system. Pyrophoric reagents are not compatible with air, moisture, oxygen/oxidizer, and protic solvents including water, acids, alcohols, amines, mercaptans, etc. Therefore, prudent safety practices must be implemented while working with these reagents in research labs.

Click to view the Pyrophoric Handling Table 
 

Handling 

Safety Equipment

Ensure:

  1. An appropriate fire extinguishing agent is available; (see Resources and External Links below)
  2. An eyewash is present in the laboratory and it is working;
  3. A safety shower is available within the immediate work area in the lab; and
  4. A splashguard or safety shield is available in a fume hood or in a location where the pyrophoric reaction is performed to prevent skin contact.

Personal Protective Equipment (PPE)

Always wear PPE while working with pyrophoric chemicals. Exact PPE selection should depend on the severity of hazards associated with individual chemicals and handling processes.

  1. Do not wear clothing made of flammable synthetic materials such as polyester, nylon, spandex, acetate and polypropylene under PPE.
  2. Wear eye protection with chemical splash goggles or safety glasses with side shields and a face shield for additional protection as appropriate for the pyrophoric chemical reactions.
  3. If an explosive reaction is possible, a face shield and process safety shield are needed.
  4. Double nitrile gloves should be sufficient for handling research scale quantities of pyrophoric reagents in a research lab.
  5. Wear flame resistant gloves when handling large quantities of pyrophoric reagent in the lab. Nomex® fabrics provide better protection against pyrophoric chemicals and flammable liquids.
  6. Wear a flame-resistant lab coat, particularly if your experiment will use larger quantities or involves tasks with additional risk of the material potentially becoming exposed to air. Fire resistant lab coats made of Nomex® fabrics are recommended because synthetic clothing such as polyester or nylon can result in severe thermal burns from pyrophoric reagent spills. Nomex® fire resistant lab coats can be purchased from Thermo Fisher, Grainger, and other lab safety supply companies.

Prudent Safety Practices

  1. Do not work alone when handling pyrophoric reagents, especially organic lithium reagents and alkali metal hydrides.
  2. Notify others in the laboratory prior to working with pyrophoric reagents.
  3. Pyrophoric reagents must be stored under a blanket of an inert gas such as nitrogen before and after each dispensation from Sure/Seal™ bottles. Pyrophoric reagents can be handled and stored safely if exposures to atmospheric oxygen and moisture are avoided.
  4. Do not store pyrophoric chemicals with other flammable materials or in a flammable solvents storage cabinet.
  5. Do not use pyrophoric chemicals near flammable solvents.
  6. Use the smallest quantity of pyrophoric chemicals possible.
  7. Perform all pyrophoric reagent transfers in a fume hood with the sash positioned at the lowest possible height.
  8. Utilize a splashguard or safety shield whenever possible.
  9. Use the original Sure/Seal™ bottles for storing and dispending pyrophoric liquids by using a syringe or double-tipped needle. With proper handling and capping techniques, the Aldrich Sure/Seal™ cap that came with the original container can be used multiple times.
  10. Conduct a hazard evaluation and process risks reduction assessment, and perform “dry runs” without pyrophoric reagents.
  11. Practice reagent transfer procedures using a ‘pyrophoric reagent-free’ solvent.
  12. Deactivate or hydrolyze excess pyrophoric reagents and their residues using an appropriate hydroxyl solvent as per your lab SOPs before discarding any empty containers.

Depiction of Sure/SealTM Bottle Inert Gas Purge

Spill/Exposure Procedures

Keep spill response materials close to the pyrophoric work location. Once a pyrophoric material begins burning, it can be very difficult to extinguish.

  1. Pyrophoric-specific spill adsorbents and fire extinguishing materials include dry sand, powdered soda ash (sodium carbonate), calcium oxide (lime), Celite® (diatomaceous earth), and clay based kitty litter. 
  • Copious amounts of these materials should be used to completely cover/smother any pyrophoric spill in the research lab to minimize fire breakout. 
  • A small beaker filled with sand can be used to safely extinguish small fires occurring at the tips of needles used to transfer liquid pyrophoric reagents.
  1. The recommended fire extinguisher is a standard dry powder (ABC) type. Class D extinguishers are recommended for combustible solid metal fires (such as sodium), but not for organolithium reagents. 
  • A CO2 fire extinguisher is not effective against pyrophoric reagents.
  1. If the fire cannot be extinguished: 
  • Call the Fire Department - Press 911.
  • Turn off all ignition sources and vacate the laboratory immediately. Confine the fire by closing the doors.
  • Activate (pull) the nearest manual fire alarm, if there is one.
  • Alert others in your area.
  • Meet the Fire Department when they arrive.

UI Public Safety must be notified of all fire-related incidents. Dial 335-5022.

After the use of a fire extinguisher, UI Facilities Management - Work Control Center should be contacted to obtain a replacement.

Emergency/Medical Treatment 

Call 911 for medical emergencies.

If pyrophoric reagents are not washed off immediately after the exposure, severe skin burn will occur. Even at very low concentrations, pyrophoric reagents will be irritating to the respiratory tract, eyes, and skin.

  1. If a person is exposed to fire or is on fire, the use of the “stop-drop and-roll” method, a safety shower, fire blanket, or fire extinguisher are the most effective means of extinguishing fire that is on fire.
  2. The affected skin area should be immediately rinsed off with copious amount of water at least for 15 to 20 minutes using the safety shower or eye wash as appropriate. This emergency procedure should be followed to ensure all pyrophoric chemicals are washed away from the affected skin area. Then researchers should seek medical attention for pyrophoric reagents related skin burn by going to the UI Occupational Health or UIHC emergency treatment center (ETC) as appropriate.
  3. If the spill occurred near the eye, eyelid or eyelash area, irrigate eyes with water for at least 20 minutes and proceed to ETC for medical attention without further delay.
  4. Additional medical treatment/consultation should follow with an appropriate medical specialist for eyes and/or skin burns.

Waste Disposal

  1. Any container with residual pyrophoric chemicals must be stored under slightly positive nitrogen pressure in the headspace and these containers should NEVER be opened to the atmosphere.
  2. If a pyrophoric chemical that is stored in a solvent has dried out, then it must be CAREFULLY diluted within a fume hood with the solvent in which the reagent was originally stored. Use the laboratory’s specific SOP for dilution of pyrophoric reagents.
  3. For any significant amount of reagent remaining in the reagent bottle, first ensure that the bottle is purged with inert gas. Place a secondary container such as a sealable plastic bag (or the manufacturer supplied aluminum can in which the bottle was shipped) into an inert atmosphere and purge it with inert gas. Put the reagent bottle into this purged secondary container and seal for EHS pickup.
  4. With continuous purging of the headspace using inert gas flow, small amounts of liquid pyrophoric reagents and rinsates can be safely hydrolyzed/quenched by the drop-wise addition of reagents and rinsates into a reaction flask or a beaker containing isopropanol or isobutanol, while making sure that the container is kept in a cryogenic dry ice/isopropanol bath.
  5. If only trace amounts of the reagent remain in the reagent container, purge the container headspace with inert gas and triple rinse the reagent container using the solvent in which the reagent was originally stored. Rinsates can then be hydrolyzed as described above. Also, the above procedure should be followed for rinsing empty septa-sealed pyrophoric reagent bottles (such as Sure/Seal™ bottles) and rinsed off with water prior to disposal in a sharps container.
  6. Reaction mixtures containing pyrophoric reagents including BuLi, Grignard reagents, LiAlH4, NaBH4 and other reactive agents should be carefully and completely quenched with hydroxyl solvents before combining these with other waste solvents or packaging for disposal by EHS.
  7. Rinsate(s) resulting from quenching reactions should be collected in a waste solvent container.
  8. Expired or unused reagent will be disposed of by EHS in the original commercial bottle. There is no need to empty, quench, or rinse these containers. Refer to earlier directions to add an appropriate solvent to containers when the solvent has dried out, prior to disposal by EHS.
  9. EHS will not accept pyrophoric chemicals for disposal when they are in an unstable condition or in a condition unsuitable for safe transportation. The laboratory may be responsible for the cost of stabilization if laboratory staff is unable to stabilize the chemicals or make them safe for transportation.
  10. Hazardous chemical waste containers must be properly labeled for EHS pickup. All materials that contain or are contaminated with pyrophoric reagents should be disposed of as hazardous waste by submitting the online request for Hazardous waste pick-up.

Training

The PI is responsible for SOPs specific to use of this chemical in their lab. The PI/Lab Manger is responsible for the site specific and hands-on training for the use of this chemical in their lab. Training should be directly documented in the researcher’s lab notebook. On each day of training, both trainer and trainee should sign the lab notebook. 

Initially, researchers should perform the reactions with the PI or senior researcher present to observe the safe handling of this chemical. Review the reagent-specific safety data sheets (SDSs). Evaluate the hazards associated with the chemical reaction and experimental setup.

Suggested hands-on training topics:

  1. Emergency preparedness and response related to the use of pyrophoric material.
  2. The use of Sure/Seal™ bottles.
  3. The safe use of glove boxes, if applicable.

Resources

External Links