Pyrophoric Reagents Handling in Research Labs

  1. Purpose and Applicability
  2. Hazards
  3. Training
  4. Safety Equipment
  5. Personal Protective Equipment (PPE)
  6. Prudent Safety Practices
  7. Emergency/Medical Treatment
  8. Spill Procedures
  9. Waste Disposal
  10. Other Useful References

Purpose and Applicability

This generic chemical safety guidance describes basic prudent safety practice for handling pyrophoric reagents in research labs. Pyrophoric reagents react with air or moisture in air; this reaction can readily lead to fire.

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.

Hazards

Pyrophoric (pyrophorus or fire bearing) reagents such as organolithium compounds (alkyl-, alkenyl-, and alkynyl- lithium, etc.) can ignite spontaneously in air. 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 at the Carnegie Mellon EHS website and in Bretherick’s Handbook of Reactive Chemical Hazards.

Pyrophoric Type GHS Pictogram and Signal Word Example
Grignard reagents


Pictogram 1
Danger
Alkyl or aryl magnesium halide (RMgX, ArMgX)
Metal alkyls and metal aryls
pictorgram 2

Danger
Tertiary butyl lithium (tert. BuLi), trialkyl aluminum (R3Al), dialkyl zinc (R2Zn), trialkyl arsenic (R3As), etc.

Metal carbonyls

pictogram

Danger

Ni(CO)4, Fe(CO)5, Co2(CO)8, etc.
Alkali metals
pictogram

Danger
Cesium, lithium, potassium, sodium, etc.
Metal powders

capture

Danger
Examples include cobalt (Co), iron (Fe), zinc (Zn), and zirconium (Zr).
Metal hydrides
pictogram

Danger
Sodium hydride (NaH), potassium hydride (KH), lithium aluminum hydride (LiAlH4), sodium borohydride (NaBH4), etc.
Nonmetal hydrides
capture

Danger
Diethylphosphine (R2HP), trialkyl phosphine (R3P), trialkyl borane(R3B), tetramethyl silane, (R4Si), etc.
Nonmetal
pictogram

Danger
White phosphorus
Pyrophoric gases
pictogram

Danger

Diborane (B2H6), dichlorosilane (R2SiH2), silane (SiH4), phosphine (PH3), arsine (AsH3), etc.

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.

Training

A. Review the safety procedures for handling highly reactive air sensitive or moisture sensitive reagents

Everyone working with these compounds should be familiar with the Aldrich technical bulletins including:

  1. AL-134 Handling Air-Sensitive Reagents
  2. AL-164 Handling Pyrophoric Reagents
  3. Air-Sensitive Compound Guidelines
  4. Air-Sensitive Techniques
  5. Transferring Air-Sensitive Reagents

Videos providing training on pyrophoric chemicals handling include:

  1. The University of California, San Diego (UCSD) video, and
  2. The Dartmouth Safety Video on Handling Pyrophoric Materials in Research Labs.

B. Receive hands-on training

  1. Researchers need hands-on training in emergency preparedness and response related to the use of pyrophoric material prior to beginning any experiments.
  2. Researchers should review the reagent-specific safety data sheets (SDSs) and evaluate the hazards and perform risk assessments associated with a chemical reaction and experimental setup.
  3. Researchers must receive approval from the PI and hands-on training from an experienced senior researcher in the lab before starting to work with any pyrophoric chemicals.
  4. Researchers should receive hands-on training in the use of Sure/Seal™ bottles under the supervision of a senior researcher who has the practical experience in handling and dispensing pyrophoric reagents from Sure/Seal™ bottles.
  5. Initially, researchers should perform the pyrophoric reactions with the PI or senior researcher present to observe the safe handling of pyrophoric reagents and feedback.
  6. If glove boxes are used, the researcher needs hands-on training from the PI or the lab supervisor on the safe use of the specific glove box used.
  7. 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.​

Depiction of Sure/Seal™ Bottle Inert Gas Purge

                                                

depiction of sure seal bottle inert gas purge

Safety Equipment

Ensure:

  1. An appropriate fire extinguishing agent is available;
  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 splash guard or safety shield is available in a fume hood or in a location where the pyrophoric reaction is performed to prevent skin contact.

Examples of Emergency Safety Equipment

                           

examples of emergency safety equipment

Personal Protective Equipment (PPE)


  • Nomex®  fabrics provide better protection against pyrophoric chemicals and flammable liquids.
  • Do not wear clothing made of flammable synthetic materials such as polyester, nylon, spandex, acetate and polypropylene under PPE.​​​

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

  1. 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.
  2. If explosive reaction is possible, a face shield and process safety shield are needed.
  3. Double nitrile gloves should be sufficient for handling research scale quantities of pyrophoric reagents in a research lab.
  4. Wear flame resistant gloves when handling large quantities of pyrophoric reagent in the lab. Nomex® flight gloves can be worn with thin 4 mil nitrile gloves as glove liners.
  5. 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


Pyrophoric reagents can be handled and stored safely if exposures to atmospheric oxygen and moisture are avoided.


  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.
  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 splash guard 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.

Aldrich Technical Bulletin on Handling Air Sensitive Reagents

aldrich technical bulletin on handling air sensitive reagents

Emergency/Medical Treatment

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. 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 HealthWorks or UIHC emergency treatment center (ETC) as appropriate.
  2. 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 treatment without further delay.
  3. Additional medical treatment/consultation should follow with an appropriate medical specialist for eyes and/or skin burns.
  4. 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.
  5. Call 911 for medical emergencies.

Spill Procedures

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

  1. 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.
  2. The recommended fire extinguisher is a standard dry powder (ABC) type.
  3. 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.
  4. Seek additional help to clean-up a large spill of pyrophoric chemicals. Turn off all ignition sources and vacate the laboratory immediately.
  5. UI Public Safety must be notified of all fire related incidents.

Extinguish only if you can do so safely and quickly

  • After the fire is extinguished, call UI Public Safety – Dial 335-5022.
  • In case of emergency - Press 911.

If the fire cannot be extinguished:

  • Confine the fire by closing the doors.
  • Activate (pull) the nearest manual fire alarm, if there is one.
  • Call the Fire Department - Press 911.
  • Alert others in your area.
  • Meet the Fire Department when they arrive.
  1. After the use of a fire extinguisher, UI Facilities Management - Work Control Center should be contacted to obtain a replacement.

Waste Disposal


  • 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.

  1. Any container with residual pyrophoric chemicals must be stored under slightly positive nitrogen pressure in the head space 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. Also, 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.

Other Useful References

  1. Aldrich Sure/seal™ Bottles.
  2. Sure Seal™ Bottles – Standard Operating Procedure, University of Berkley
  3. Transferring Air-Sensitive Reagents
  4. Procedures for Safe Use of Pyrophoric Organolithium Reagents Laboratory Safety Fact Sheet #34. Radiological and Environmental Management, Purdue University. 
  5. Laboratory Safety Fact Sheet #35. Lab Coats for Working with Flammable Liquids and Pyrophorics Proper Cleaning of Lab Coats, University of California, Santa Barbara (UCSB).
  6. Pyrophoric Chemicals Guide, University of Minnesota Environmental Health and Safety
  7. Standard Operating Procedure: Safe Handling of Pyrophoric Liquids, Oregon State University. 
  8. Pyrophoric Safety Training, Risk Assessment Services, University of North Texas.
  9. Pyrophoric handling Policy, Carnegie Mellon Environmental Health and Safety
  10. Procedures for Safe Use of Pyrophoric Liquid Reagents, University of California Los Angeles (UCLA) 
  11. Procedures for Safe Use of Pyrophoric Solids, University of California Los Angeles (UCLA)
  12. The Safe Use of Pyrophoric Reagents, Columbia University Environmental Health and Safety.