STANDARD OPERATING PROCEDURE
PEROXIDE FORMING CHEMICALS
(e.g. TETRAHYDROFURAN, ETHYL ETHER)
Principal Investigator:
Lab Location(s):
Emergency Contact
Information:
Annual Review Date:
Statement of Understanding and Compliance
I confirm that I have read and understand this SOP and will comply with the procedures and policies.
Name:
Signature:
Date:
NOTE: This SOP is a general SOP for peroxide forming chemicals such as ethyl ether and
tetrahydrofuran. The SOP should be edited specifically for each peroxide forming chemical you
store and use in your lab.
Before working with peroxide forming chemicals, the lab worker must have the approval of the PI
who shall provide specific training according to this SOP and in understanding the MSDS
provided by the manufacturer. The lab worker must complete UH lab safety training and
Hazardous waste generator training prior to working with any chemicals. The lab worker should
sign this SOP as documentation that he/she understands the hazards and has been trained in how
to work with peroxide forming chemicals safely.
1. INFORMATION AND PROCEDURES ABOUT USING PEROXIDE FORMING CHEMICALS
CAS#109-99-9 Tetrahydrofuran
CAS#60-29-7 Ethyl Ether
Chemicals that are susceptible to peroxide formation are ones that typically react with air, moisture or
impurities and produce a change in their chemical composition in normal storage. Certain organic
solvents are susceptible to peroxide formation and can become extremely sensitive to thermal or
mechanical shock and may explode violently. Peroxides are formed through a spontaneous reaction with
oxygen. Simply opening the container can initiate peroxide formation, while light and heat can act to
accelerate the process. Unless these materials are properly handled they can pose a serious safety
hazard to users and become a difficult disposal problem for the Environmental Health and Safety Office.
Manufacturers may add an inhibitor to peroxide forming chemicals to counter peroxide formation. For
many peroxide-forming solvents, butylated hydroxyl toluene (BHT) is commonly added. BHT scavenges
oxygen in the solvent and prevents it from reacting with the solvent to form peroxides. Over time, BHT or
other inhibitors in the solvent can become exhausted allowing peroxides to form. Distilling the solvent
can completely remove the BHT or inhibitors and make the solvent immediately susceptible to peroxide
formation.
2. CLASSES OF PEROXIDE FORMING CHEMICALS
Class A: Chemicals that form explosive levels of peroxide without concentration. These are the most
hazardous and can form explosive peroxide levels even if not opened.
Examples: Divinyl Acetylene, Divinyl Ether, Isopropyl Ether, Sodium or Potassium Amide, Vinylidene
Chloride (1,1-dichloroethylene)
The <Enter PI Name/Dept Name here> laboratory has the following Class A chemical:
Chemical Name
Storage Location Expiration Date
Date Received
Date Opened
Class B: Chemicals that form explosive levels of peroxides when concentrated through distillation,
evaporation or exposure to air after opening.
Examples: Acetal, Butadiene, Cellosolve, Cumene (isopropyl benzene), Cyclohexene, Cyclopentene,
Decalin, Diacetylene (gas), Dicyclopentadiene, Diethyl ether (ether), Dioxane, Ethylene glycol dimethyl
ether (glyme), Ethylene glycol ether acetates, Furan, Methyl Isobutyl Ketone, Methyl Acetylene (gas),
Methyl Cyclopentane, Tetrahydrofuran (THF), Tetralin (tetrahydronaphthalene), Vinyl ethers.
The <Enter PI Name/Dept Name here> laboratory has the following Class B chemicals:
Chemical Name
Storage Location Expiration Date
Date Received
Date Opened
Class C: Chemicals which are a hazard due to peroxide initiation of polymerization.
Examples: Acrylonitrile, Chlorobutadiene, Chloroprene, Chlorotrifluoroethylene (gas), Methyl
Methacrylate, Styrene, Tetrafluoroethylene (gas), Vinyl Acetate, Vinyl Acetylene (gas), Vinyl Chloride
(gas), Vinyl Pyridine,
The <Enter PI Name/Dept Name here> laboratory has the following Class C chemical:
Chemical Name
Storage Location Expiration Date
Date Received
Date Opened
3. HAZARDOUS PROPERTIES, POTENTIAL ROUTES OF EXPOSURE, SYMPTOMS OF EXPOSURE
This section must be edited to be specific to each peroxide forming chemical used and stored in
your lab.
Potential Health Effects:
Eye:
Contact with eyes may cause severe irritation, redness, pain and possible eye burns.
Prolonged exposure to high concentrations of vapor may cause eye damage. Contact may
cause ulceration of the conjunctiva and cornea. Damage may be permanent.
Skin:
May cause skin irritation. Prolonged and/or repeated contact may cause dermatitis. May be
absorbed through skin.
Ingestion: Harmful if swallowed. May cause gastrointestinal irritation with nausea, vomiting and
diarrhea. Ingestion of 1 or 2 ounces of ethyl ether may be fatal.
Inhalation: Inhalation of high concentrations may cause central nervous system effects. Causes
respiratory tract irritation. Continued exposure may lead to nausea, headache, dizziness,
unconsciousness, coma and death.
Routes of Exposure
May enter the body through all routes of exposure.
Chronic Effects:
Tetrahydrofuran: Prolonged or repeated eye contact may cause conjunctivitis. Prolonged or repeated
skin contact may cause defatting and dermatitis. May cause liver and kidney damage.
Ethyl Ether: Repeated exposures may be habit forming. Prolonged exposures may result in headache,
drowsiness, excitation, and psychic disturbances. Teratogenic effects are possible.
Aggravation of Pre-existing Conditions:
Ethyl Ether: Persons with pre-existing skin disorders or eye problems or impaired liver, kidney or
respiratory function may be more susceptible to the effects of this substance. Alcoholic beverage
consumption can enhance the toxic effects of this substance.
4. PERSONAL PROTECTIVE EQUIPMENT
This section must be edited to be specific to each peroxide forming chemical used and stored in
your lab.
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Nitrile disposable gloves. Change gloves frequently and when contaminated, punctured, or torn.
Wash hands immediately after removing gloves.
Use chemical safety goggles and/or a full face shield where splashing may occur.
A laboratory coat should be worn when working with this chemical. Impervious protective clothing,
including boots, gloves, lab coat, apron or coveralls, as appropriate, to prevent skin contact.
Closed toe shoes are required at all times when working in the laboratory. Shoes should be
conductive and nonsparking.
Ethyl Ether: If the exposure limit is exceeded and engineering controls (e.g. fume hood) are not
feasible, contact EHSO immediately. A respirator may have to be used and this requires medical
clearance, annual training and annual fit testing. A half-face organic vapor respirator may be
worn for up to ten times the exposure limit, or the maximum use concentration specified by the
appropriate regulatory agency or respirator supplier, whichever is lowest. A full-face piece organic
vapor respirator may be worn up to 50 times the exposure limit, or the maximum use concentration
specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. For
emergencies or instances where the exposure levels are not known, use a full-face piece positivepressure, air-supplied respirator. WARNING: Air-purifying respirators do not protect workers in
oxygen-deficient atmospheres. An organic vapor respirator is predicted to have short service life
(less than 30 minutes at concentrations of ten times the TLV/PEL) when used with this material.
5. ENGINEERING/VENTILATION CONTROLS
This section must be edited to be specific to each peroxide forming chemical used and stored in
your lab.
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Facilities storing or utilizing this material must be equipped with an eyewash facility and a safety
shower.
Work in a chemical fume hood is generally required because it can control the emissions of the
contaminant at its source, preventing dispersion of it into the general work area.
Use adequate ventilation to keep airborne concentrations low.
A system of local and/or general exhaust is required to keep employee exposures below the Airborne
Exposure Limits.
Tetrahydrofuran:
OSHA Permissible Exposure Limit (PEL): 200 ppm TWA
ACGIH Threshold Limit Value (TLV): 50 ppm (TWA), 100 ppm STEL
Ethyl Ether:
OSHA Permissible Exposure Limit (PEL): 400 ppm TWA
ACGIH Threshold Limit Value (TLV): 400 ppm (TWA), 500 ppm STEL
6. HANDLING AND STORAGE LIMITS FOR EACH CLASS OF PEROXIDE FORMING CHEMICALS
Class A:
Storage unopened: 6 months maximum; at 6 months, open the container and test.
Storage opened: Test upon opening
 If the test indicates >80 ppm peroxides = submit for disposal.
 If the test indicates <80 ppm peroxides = retest every 3 months and dispose when the test
indicates >80 ppm peroxides, the manufacturer expiration date is reached or one (1) year from
the date of receipt, which ever comes first.
Class B:
Storage unopened: 1year maximum; at 1 year, open the container and test.
Storage opened: Test upon opening
 If the test indicates >80 ppm peroxides = submit for disposal.
 If the test indicates <80 ppm peroxides = retest every 3 months and dispose when the test
indicates >80 ppm peroxides, or when the manufacturer expiration date is reached, which ever
comes first.
Class C:
Storage unopened: 1 year maximum; at 1 year, open the container and test.
Storage opened: Test upon opening
 If the test indicates >80 ppm peroxides = submit for disposal.
 If the test indicates <80 ppm peroxides = retest every 3 months and dispose when the test
indicates >80 ppm peroxides, or when the manufacturer expiration date is reached, which ever
comes first.
See section 7 testing procedures below.
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Minimize the quantity of peroxides or peroxide forming chemicals in the lab.
Know the properties and hazards of all chemicals you are using through adequate research and
study, including reading the label and MSDS.
Store all peroxide forming chemicals in tightly closed, air-impermeable, light-resistant containers,
away from heat, light, direct sunlight, static electricity, sources of ignition, oxidizers and oxidizing
agents.
Label each container with the Date Received, Date Opened, and Date Last Tested and test result.
Labels are available through EHSO. Do not cover or otherwise deface the original manufacturer’s
label.
Make sure caps are replaced promptly after use. Store in the original manufacturer’s container
whenever possible. Protect containers from shock, friction, and do not shake.
Test chemicals according to the schedule above and report results to EHSO.
Test chemicals for peroxides before any distillation or purification of peroxide forming chemicals. Use
extreme caution before concentrating or purifying peroxide forming chemicals as most explosions
occur during these processes.
Immediately rinse empty containers that once held peroxide-forming solvents. Do not allow residues
to evaporate. Do not attempt to open or rinse a container of unknown age and history; report these
containers to EHSO immediately!
Wear proper personal protective equipment, including safety eyewear and face shields.
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If solids or crystals are observed or visibly present on or in the container or lid, or if the chemical
shows discoloration, string-like formation, or liquid stratification, DO NOT OPEN OR MOVE THE
CONTAINER. Contact EHSO immediately.
7. TESTING
Testing for peroxides is done for most organic solvents. Testing should NOT be applied to materials that
may be contaminated with inorganic peroxides, such as metallic potassium. NEVER test containers of
unknown age or history; report these to EHSO immediately.
Peroxide Test Strips: Peroxide detection strips are commercially available from most laboratory
equipment supply vendors. Test strips are available also at the University of Hawaii Manoa Chemistry
Stockroom. Follow the manufacturer’s instructions for storing and using the product. Observe any
product expiration dates to ensure adequate detection. Note that these strips must be air dried until the
solvent evaporates and then exposed to moisture for proper operation.
Peroxide Forming Chemical Labels (available through EHSO) must be attached and recorded at each
testing (do not cover the original manufacturer’s label):
Chemical should be
disposed of as soon as
possible when test
results > 80 ppm
8. PROCEDURES ****Modify this section to reflect your lab specific procedures!
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Absorbent bench paper should be used with handling peroxide forming chemicals. Bench paper
should be disposed via EHSO upon contamination from spilling or after usage. Contaminated bench
paper, as well as other contaminated items, should be submitted to EHSO for disposal.
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Handling Peroxide Forming Chemicals
o Wear appropriate PPE (gloves, eye protection, lab coats, covered toe shoes).
o Change gloves after handling.
o Waste container should be properly labeled and stored appropriately until disposal.
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Work in a chemical fume hood.
All general safe work practices should be followed when working with peroxide forming
chemicals (i.e. no eating, drinking, chewing gum, washing hands immediately after removing
PPE, etc).
9. SPILL AND ACCIDENT PROCEDURES
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Do not attempt cleanup if you feel unsure of your ability to do so or if you perceive the risk to be
greater than normal laboratory operators. Call EHSO for assistance.
Isolate the area to prevent the spread of contamination (e.g. close doors to affected area, post
warning signs, alert others in immediately vicinity to evacuate or not enter area). Ventilate area of
leak or spill.
Remove all sources of ignition.
Absorb material with inert material, then place in suitable container. Do not use combustible
materials, such as saw dust.
Use water spray to dilute spill to a non-flammable mixture.
Wear appropriate personal protection.
Do not flush down the drain. Do not let this chemical enter the environment.
Report all incidents or near misses to EHSO and complete the appropriate Incident Form.
Small spills (in a chemical hood):
Don appropriate PPE. Cover spills of peroxide forming chemicals with absorbent material, and
clean surfaces with water. Collect spilled material and clean up material into appropriately
labeled waste container. All spill clean up material should be disposed of as hazardous waste.
Large spills / Spills outside of a chemical hood:
Notify others in room of spill. Evacuate room/immediate area. Call Security and EHSO. Close
doors and post warning signs at entrances/exits notifying others of spill. Prevent unnecessary
entry into area. Provide assistance and information to spill responders.
**Report all spills (minor and major) and any near misses to EHSO.
10. FIRST AID MEASURES
Eye Contact:
Immediately flush eyes with plenty of water for at least 15 minutes, lifting lower and upper
eyelids occasionally. Get medical attention immediately.
Skin Contact: Wipe off excess material from skin, then immediately flush skin with plenty of soap and
water for at least 15 minutes. Remove contaminated clothing and shoes. Get medical
attention immediately.
Ingestion:
Do not induce vomiting. If victim is conscious and alert, give large quantities (2-4 cups)
of milk or water. Never give anything by mouth to an unconscious person. Get medical
attention immediately. Wash mouth out with water.
Inhalation:
Remove from exposure and move to fresh air. If breathing is difficult, give oxygen. If not
breathing, give artificial respiration. Get medical attention immediately.
11. WASTE DISPOSAL PROCEDURES
Tetrahydrofuran and Ethyl Ether are listed as a Class 3 Flammable hazardous material and must be
submitted to EHSO for proper disposal. Gloves, test tubes, pipette tips, and paper towels, etc. that are
contaminated with the chemical should also be collected for hazardous waste pickup by EHSO. Drain
disposal of peroxide forming chemicals is NOT permitted.
Empty containers of peroxide forming chemicals can still pose a significant hazard. The containers
should be triple rinsed and the rinsate collected for disposal as hazardous waste immediately after the
last amount is removed. If after triple rinsing the container is deemed to be free of residue, the label may
be removed or crossed out and the container can be discarded into the regular trash. If the container
cannot be rinsed completely, it must be turned into EHSO as hazardous waste.
12. MSDS LOCATION ****Where is this located, as an attachment to the SOP, in the MSDS folder,
etc? Must have an MSDS, preferably manufacturer specific, specific for each type of peroxide
forming chemicals used (per CAS#).
References: Information contained in this SOP was gathered from the following sources: University of
Nebraska Lincoln, New Mexico State University, Fisher Scientific, Mallinckrodt Baker Inc.