Last Revised: April 12, 2024
Revision 1/2022 (KB)
Hazard Description
Pyrophoric chemicals are liquids, solids, and gases that will ignite spontaneously in air at or below 130 °F.
Oxidation of the compound by oxygen or moisture in air proceeds so rapidly that ignition occurs. Many finely divided metals are pyrophoric, and their degree of reactivity depends on particle size, as well as factors such as the presence of moisture and the thermodynamics of metal oxide or metal nitride formation. Other reducing agents, such as metal hydrides, alloys of reactive metals, low-valent metal salts, and iron sulfides, are also pyrophoric.
From Prudent Practices in the Laboratory: Handling and Management of Chemical Hazards (section 4.D.2.2 Pyrophorics) The National Academies Press: Washington, DC, 2011.
A list of some example pyrophoric materials is given in the section below called "List of Pyrophoric Chemicals"
You can check your lab's chemical inventory records for pyrophoric materials using the instructions in this EHRS ChemTracker Tip Sheet: Hazard List Analysis.
Approvals
A Hazard Control Plan is required for this class of hazardous chemicals
All work with pyrophoric chemicals requires the approval of the P.I. The P.I. must ensure that the person or team who will be working with the pyrophoric chemical writes a task-specific Hazard Control Plan (HCP). The HCP must be sent to EHRS for review. EHRS will upload the HCP to the “documents” section of the lab’s BioRAFT page.
The P.I. must also ensure that the the person or team who will be working with the pyrophoric chemical understands the hazards and has received adequate training and supervision for the procedure.
EHRS Notification and Approval
- Labs groups who have never used pyrophoric chemicals before and are planning to do so for the first time must notify EHRS prior to starting their work.
- Notify EHRS if planning an experiment requiring large quantities (greater than 100 mL of liquid or 10 g of solid) of pyrophoric materials.
- The use of pyrophoric gases requires EHRS approval. If you anticipate the need to use pyrophoric gases in your work, contact Karen Kelley, Associate Director of Lab Safety and Industrial Hygiene Programs, at kelley@upenn.edu or 267-667-2496.
Training Requirements
No researcher may work independently with the hazardous material described in this SOP until the Principal Investigator (or their designee) has ensured that the researcher:
- Has completed all required EHRS laboratory safety training programs
- Understands the hazards of the materials and risks of the processes involved
- Has read and understands the contents of this SOP and the lab's task-specific Hazard Control Plan
- Demonstrates the ability to execute their work according to the requirements in this SOP and the lab's task-specific Hazard Control Plan
All users of pyrophoric reagents in the laboratory must receive hands-on instruction from an experienced senior member of the laboratory (Principal Investigator or Post-Doctoral Fellow) and must be closely supervised until safe work practices are consistently demonstrated. This training must be documented so that proof of training is available upon request.
Facility Requirements
General Ventilation
Pyrophoric chemicals may not be handled or stored in a room or facility with recirculating exhaust.
Chemical Fume Hood or Glovebox
All work with pyrophoric chemicals in open or closed systems must be done in a designated area of a laboratory inside of a properly functioning chemical fume hood or glove box.
Emergency Irrigation
Emergency irrigation (safety shower, eyewash) must be accessible within a 10-second travel distance of the area where the work is performed.
Signage and Labeling
A legible manufacturer’s label including hazard information must be present on all commercial containers of pyrophoric chemicals.
If commercially purchased pyrophoric chemicals are transferred to another container for storage or to make stock solutions for later use, special labeling requirements apply. See the “Researcher-Created Labels” section in Section IV: Chemical Container Labeling in this CHP for a complete list of requirements.
Date Containers
Write on the container label the date that a pyrophoric material was received and the date the container was opened.
Storage and Transport
The Hazard Control Plan for your lab's procedures involving pyrophoric compounds will detail any specific storage conditions and restrictions that apply to your materials.
Proper storage and transport of pyrophoric chemicals must be determined by assessing all of the hazards and physical properties of the chemical.
All hazardous chemicals, including pyrophoric materials, must be tracked in the lab's chemical inventory.
See Section VI: Chemical Storage and Transportation in this CHP for a complete list of requirements.
Special Considerations for Storage of Pyrophoric Compounds
- Pyrophoric chemicals must be stored under an atmosphere of inert gas or under an appropriate liquid.
- Do not store pyrophoric chemicals with flammable materials or in a flammable-liquids storage cabinet where other flammable chemicals are stored.
- Store these materials away from sources of ignition.
- Minimize the quantities of pyrophoric chemicals stored in the laboratory.
- Store bottles of liquid pyrophorics inside the original metal shipping can, if available, to provide additional protection/secondary containment.
- Never return excess chemicals to the original container. Small amounts of impurities may be introduced into the container which may cause a fire or explosion.
- Date containers upon initial receipt and upon opening. Take note of any printed expiration dates on the container label and dispose of them as required. Many pyrophoric reagents become unstable or more dangerous with age.
Hazard Controls
The Hazard Control Plan for your lab's procedures involving pyrophoric compounds will detail specific engineering controls, work practices, or personal protective equipment that is required.
Some general guidance is given below.
Engineering Controls
Chemical Fume Hood
All work with pyrophoric chemicals in open or closed systems that is not performed inside of an inert atmosphere glove box must be done in a designated area of a laboratory inside of a properly functioning chemical fume hood.
Many pyrophoric chemicals release noxious or flammable gases. Some solid 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 in the laboratory.
The fume hood is designed to capture chemical vapor and the hood sash acts as a shield in case of chemical splash. The sash must be kept closed as much as feasible.
Blast Shield
Safety shielding is required any time there is a risk of explosion, splash hazard or a highly exothermic reaction. All manipulations of pyrophoric chemicals which pose this risk should occur in a fume hood with the sash in the lowest feasible position. A portable blast shield may be placed in front of a vessel containing a highly reactive material. This provides additional protection in the case of a violent reaction. Your lab's task-specific Hazard Control Plan will specify whether a blast shield is required for your process.
Vacuum Protection
Evacuated glassware can implode and eject flying glass, and splattered chemicals. Vacuum work involving pyrophoric chemicals must be conducted in a fume hood or isolated in an acceptable manner.
Mechanical vacuum pumps must be protected using cold traps and, where appropriate, filtered to prevent particulate release. The exhaust for the pumps must be vented into an exhaust hood. Vacuum pumps should be rated for use with pyrophoric chemicals.
For more information about vacuum protection see the CHP Fact Sheet on Vacuum Pumps.
Glove Box
Glove boxes must be used to handle pyrophoric chemicals if sufficient inert or dry atmospheres cannot be achieved using a vacuum gas manifold. The Office of Environmental Health and Radiation Safety (8-4453) or the Principal Investigator will determine if this is required.
If a chemical fume hood or glove box is not available, contact EHRS to determine whether the risks can be adequately controlled using alternative controls.
Gas Cabinet
Ventilated compressed gas cylinder storage cabinets are required for pyrophoric gases. Consult EHRS before purchasing any pyrophoric gases.
Work Practices
A list of recommended work practices for hazardous chemical handling is included in Section V: Chemical Handling in this CHP. Of particular relevance to pyrophoric chemical use:
Considerations for purchase
- Do not use pyrophoric chemicals if less-hazardous alternatives are possible.
- Purchase pyrophoric reagents in the minimum quantity required for the work to be performed. Initial cost per volume/weight may be lower when reagents are purchased in bulk, but repeated opening of containers and puncturing of septa leads to product degradation and loss. Wasted material and disposal cost will often offset any initial savings.
- Purchase the lowest concentration of pyrophoric chemicals that will meet your research needs.
Considerations for work space
- Work with pyrophoric chemicals in areas that you've designated especially for this work.
- Post a sign on the fume hood when a process involving pyrophoric chemicals is unattended. A template is available for download: Unattended Operations Sign Template
- Remove all other chemicals and hazardous materials from the work area.
- Remove combustible materials from the work area.
Considerations for handling
- Do not handle pyrophoric chemicals when working alone.
- Notify other lab occupants when you work with pyrophoric chemicals is in progress.
- Immediately close all containers of pyrophoric chemicals after use and return them to their designated storage location.
The Sigma-Aldrich Technical Bulletins “Handling of Air-Sensitive Reagents (AL-134)” and “The Aldrich Sure/PacTM System (AL-136)” provide guidance on the safe transfer of air-sensitive and pyrophoric liquids. These documents are meant as references are not a substitute for hands-on training and supervision or a replacement for a lab-specific Hazard Control Plan.
When performing small-volume liquid transfers of pyrophoric materials, it is not appropriate to use a luer-slip syringe type, because the needle can easily detach from the syringe barrel. Luer-lock or integrated-needle syringes must be used with these chemicals.
Additional work practices for reducing the risks of any lab procedure involving pyrophoric chemicals must be described in a written Hazard Control Plan.
Personal Protective Equipment
Consider the potential routes of exposure and health consequences when selecting personal protective equipment (PPE) for tasks involving pyrophoric chemicals.
In addition to the minimum lab apparel and PPE requirements, other protective equipment may be necessary to reduce risks. When additional equipment (such as tight-fitting chemical splash goggles, chemical-resistant gloves, or disposable lab coats) are required, a Hazard Control Plan must be written to document the risk assessment and controls.
Unless work will be performed in a glove box, it is highly recommended that a fire-resistant lab coat be worn while manipulating quantities of liquid pyrophorics over 10 mL or solid pyrophorics over 1 gram. Contact EHRS before ordering fire-resistant lab coats, as some garments offer better protection than others. There are often strict requirements for laundering in order to maintain the fire-resistant properties of the garments. EHRS will recommend the right product for your lab's needs.
Disposable nitrile gloves provide adequate protection against accidental hand contact with small quantities of most laboratory chemicals, but are highly combustible. Consider the use of Nomex/Leather pilot’s gloves, which provide fire resistance without compromising manual dexterity. The pilots gloves should be worn over nitrile gloves and are recommended during syringe/cannula transfers of pyrophoric liquids.
Contact EHRS for general assistance with risk assessments, glove compatibility, and other PPE selection.
The minimum PPE requirements for all chemical handling tasks, and information about specialty PPE can be found in the "Personal Protective Equipment" section of Section V: Chemical Handling in this CHP.
Waste and Decontamination
The Hazard Control Plan for your lab's procedures involving pyrophoric chemicals will detail specific procedures for spills, decontamination of surfaces, and collection of hazardous waste.
Some general guidance is given below.
- Wash hands thoroughly with soap and water after handling any chemical and whenever you leave the lab.
- Use good housekeeping practices to avoid contamination of surfaces, garments, personal belongings, and self.
- Decontaminate all surfaces that have come in contact with pyrophoric chemicals and clean-up small spills promptly. See the chemical Safety Data Sheet or contact EHRS for assistance with determining an appropriate decontamination method. See “Spills” below for instruction on what to do in the event of a large or hazardous spill of a pyrophoric chemical.
Waste Collection and Disposal
See the page Disposal of Highly Reactive Reagents for guidance on how to dispose of unused or expired highly reactive chemicals.
For complete hazardous waste guidelines, see the waste section of the EHRS website: Laboratory Chemical Waste Management Guidelines
Emergencies
Emergency Contacts
General emergency response information can be found on the Emergency Info page.
Spills
Anticipate spills by having the appropriate clean-up equipment on hand. The appropriate clean-up supplies can be determined by consulting the safety data sheet or will be included in your lab's task-specific Hazard Control Plan. Spill control materials for pyrophoric chemicals are designed to be inert and will not react with the reagent.
Planning for spills must occur prior to the use of any pyrophoric chemicals.
General procedures for chemicals spill response can be found in Section X: Chemical Spills in this CHP.
Do not hesitate to call EHRS for assistance with spill cleanup for pyrophoric materials.
24 hours: 215-898-4453
Contact Penn Police (511) only if the spill involves a fire, imminent risk of fire, an injury requiring an ambulance, or if there is a hazard that may affect others in the building.
Fires
During a fire emergency, the University of Pennsylvania’s Division of Public Safety – Fire and Emergency Services (FES) emphasizes safe evacuation as top priority. If you discover a fire or fire-related emergency, such as abnormal heating of material, hazardous gas leaks, hazardous material or flammable liquid spill, smoke, or odor of burning; immediately follow the procedures on the Emergency Info: Fire page.
Many pyrophoric reagents must not be extinguished using a CO2 fire extinguisher. Many pyrophoric materials fires can be classified as a “Class D: Combustible Metals” fire. While a Class D fire extinguisher is, per OSHA, required for labs working with materials that could cause a Class D fire, FES discourages their use in favor of evacuation. This is because not all Class D fires can be extinguished by any one kind of Class D fire extinguisher. Furthermore, Class D fires are prone to re-ignite and Class D fire extinguishers often have a lower effective range than other classes of fire extinguishers, making Class D fires difficult to fight safely and effectively. Determination of how to extinguish a Class D fire is best left to emergency responders. Your role is to inform them of what materials are fueling the fire.
Small incipient fires with an exotic fuel source (e.g. pyrophoric or explosive chemicals, reaction mixtures containing highly corrosive, toxic, or other hazardous chemicals) may be attempted to be immediately smothered using sand, powdered lime, or a similar dry extinguishing agent. A dry extinguishing must be readily available where work is performed. Small fires occurring at the tips of needles used to transfer liquid pyrophorics can be extinguished by immersing them in a beaker of such a dry extinguishing agent.
If using sand, powdered lime, or a similar dry extinguishing agent does not immediately put out the fire, do not continue fighting the fire; evacuate the area and notify emergency services as described on the Emergency Info: Fire page.
List of Pyrophoric Chemicals
Examples of Pyrophoric Reagents Commonly Found in Laboratories
Liquids/Solutions
Organolithiums
- Alkyl and Aryl Lithiums
- n-butyllithium, t-butlylithium
- Lithium Amides
- Lithium Alkoxides
Organomagnesiums “Grignard Reagents”
- Alkyl and Aryl Magnesium Halides
- Methylmagnesium Chloride, Allylmagnesium Bromide
Organozincs
- Diethyl Zinc
Aluminum Alkyls
- Trimethylaluminum
- Diisobutylaluminum hydride
Metal Carbonyls
- Nickel Carbonyl
- Iron Pentacarbonyl
Silicon Halides
- Dichloromethylsilane
Solids (may also come as solutions)
Metal Hydrides
- Sodium Hydride
- Potassium Hydride
- Lithium Aluminum Hydride
Finely Divided Metals
- Aluminum
- Lithium
- Magnesium
- Titanium
- Zinc
- Zirconium
- Sodium
- Potassium
Used Hydrogenation Catalysts
- Raney Nickel
- Palladium on Carbon
Gases
- Silane
- Diborane
- Phosphine
References
This SOP was based on the previous version of “EHRS SOP for Pyrophoric Chemicals” and the following additional resources:
- Prudent Practices in the Laboratory: Handling and Management of Chemical Hazards (section 4.D.2.2 Pyrophorics) The National Academies Press: Washington, DC, 2011.