SOP- Chloroform

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This standard operating procedure (SOP) outlines the handling and use of chloroform. Review this document and supply the information required in order to make it specific to your laboratory. In accordance with this document, laboratories should use appropriate controls, personal protective equipment, and disposal techniques when handling chloroform.

Chloroform (CAS # = 67-66-3) is a clear, colorless liquid with a pleasant, nonirritating odor that can be detected as low as 11.7 ppm (odor threshold) but more likely detected at levels of 85 to 307 ppm (well above safe exposure limits).

Synonyms include: Trichloromethane, Methane trichloride, Formyl trichloride, Trichloroform, Methenyl trichloride and Freon 20.

Caution. Chloroform will degrade in the presence of heat, UV light, air and certain metal catalysts resulting in the generation of phosgene, a highly toxic gas/liquid, with a characteristic odor of cut hay/grass. If exposure to phosgene is suspected, immediately notify your supervisor and seek medical attention.

NOTE: Stabilizers are often added to prevent oxidation and generation of hydrochloric acid and phosgene:

Common stabilizers include ethanol at concentrations of 1% and amylene (or pentene) at concentrations of 100 ppm. Amylene is often used as a stabilizer in analytical applications where pure-grade chloroform is needed; however, there is evidence that amylene is not an effective stabilizer.      

Chloroform is used as an extractant solvent in manufacture of rubber, essential oils, sterols and alkaloids, guttapercha, resins, and in the recovery of fat from waste products; in chemical analysis and assays; and in photographic processing. It is also used as a general solvent of lacquers, plastics, dyes, fats, greases, gums, oils, adhesives, and waxes, and in the rubber cleaning and dry cleaning industries.

Useful Chloroform Links:

Potential Hazards

• Chloroform has been classified as a potential to probable human carcinogen, based on adequate evidence for carcinogenicity in animals. Some animal studies also show evidence of reproductive and developmental toxicity from chloroform exposure.

• Inhalation of vapors can cause headaches, drowsiness, dizziness, and nausea. At high concentrations disorientation, anesthetic effects, and unconsciousness can occur, but acute toxicity is low.

• Chloroform is an eye, skin and upper respiratory tract irritant.

• Chloroform is not combustible but exposure to fire or high temperatures may lead to formation of phosgene, hydrogen chloride (HCl) and chlorine, all highly toxic gases.

• Chloroform should be treated as a time-sensitive chemical, similar to peroxides.  Chloroform that is not stabilized has a very short shelf-life and should be purchased in small quantities. Chloroform stabilized with amylene has a shelf-life <12 months. There is evidence that ethanol, which is present at greater concentrations, is a better stabilizer; chloroform stabilized with ethanol typically has a shelf life of 5 years.

• Consult the SDS for Chloroform for additional guidance and information.

• Many manufacturers provide information on the lot manufacturer date on their website.

Occupational Exposure Limits (OELs): • MIOSHA: 2 ppm, 8-hour PEL

Engineering Controls

Work with chloroform in a chemical fume hood. Dilute solutions (< 10%) may be used on the benchtop in small quantities (< 500 mL).

Work Practice Controls

• Date chloroform bottles when received.

• Keep containers of chloroform closed as much as possible and store away from light.

• Be aware of skin absorption as a possible route of exposure. Plan work so that minimal glove contact is expected, and purchase appropriate gloves for cleaning up small spills. (Refer to the PPE section below, for glove recommendations.)

• Use in the smallest practical quantities for the experiment being performed.

• Do not mix or store with acids; may form toxic gas.

• Thoroughly wash hands when finished handling.

• Chloroform that has exceeded the expiration date should be disposed of as a hazardous waste.

• It may be prudent to test for a low pH as an indicator of HCl and phosgene prior to use (in the fume hood).

• The presence of phosgene can also be detected by preparing indicator strips as follows: Strips of filter paper are dipped in 5% w/v Diphenylamine and 5% w/v Dimethylaminobenzaldehyde in an alcoholic solution (ethanol works fine) and then allowed to dry. Strips should be a very light yellow when dry, and activate to a dark yellow/orange color upon presence of phosgene.

Personal Protective Equipment (PPE)

• The minimum PPE for work with chloroform is Viton or PVA (Polyvinyl Acetate) laboratory gloves, lab coat, and safety glasses (ANSI/ISEA Z87.1 approved). Keep in mind that chloroform will penetrate nitrile gloves in less than 2.5 minutes.

• If a splash may occur, wear chemical splash goggles and/or a face shield.

• OSEH’s Glove Compatibility webpage can also be used to determine the recommended gloves.

Transportation and Storage

• Do not store chloroform with incompatibles. Chloroform is not compatible with the following: acetone, strong bases, alkalis, chemically-active metals (such as aluminum, magnesium, sodium, or potassium), dinitrogen tetroxide, fluorine, disilane, sodium methylate, triisopropylphosphine, and solid potassium tert-butoxide.

• Transport chloroform in secondary containment, preferably a polyethylene or other non-reactive acid/solvent bottle carrier.

• Store in secondary containment.

• Avoid storing on the floor.

Waste Disposal

Because most spent, unused and expired chemicals/materials are considered hazardous wastes, they must be properly disposed of. Do not dispose of chemical wastes by dumping them down a sink, flushing in a toilet or discarding in regular trash containers, unless authorized by OSEH Hazardous Materials Management (HMM). Contact OSEH-HMM at (734) 763-4568 for waste containers, labels, manifests, waste collection and for any questions regarding proper waste disposal. Also refer to OSEH’s Hazardous Waste webpage for more information.

Exposures/Unintended Contact

 If the employee is in need of emergency medical attention, call 911 immediately.   

• Eyes: In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Get medical aid.

• Skin: In case of contact, immediately flush skin with plenty of water. Remove contaminated clothing and shoes. Get medical aid. Wash clothing before reuse.

• Ingestion: Get medical aid immediately. Do not induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. If vomiting occurs naturally, have victim lean forward.

• Inhalation: If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical aid. 

Contact OSEH for advice on symptoms of chemical exposure, or assistance in performing an exposure assessment.

Report all work related accidents, injuries, illnesses or exposures to Work Connections within 24 hours by completing and submitting the Illness and Injury Report Form. Follow the directions on the Work Connections website Forms Instructions to obtain proper medical treatment and follow-up.

Complete the OSEH Laboratory Incident and Near-Miss Report form.


U-M Occupational Health Services -- Campus Employees Mon-Fri 7:30 am - 4:30 pm

After hours - go to UM Hospital Emergency Dept. – Urgent Care Clinic C380 Med Inn building 1500 East Medical Center Drive, Ann Arbor (734) 764-8021

University Health Services -- University students (non-life threatening conditions) Mon-Fri 8 am – 4:30 pm, Sat 9 am – 12 pm Contact for current hours as they may vary 207 Fletcher Street, Ann Arbor (734) 764-8320

UMHS Emergency Department -- after clinic hours or on weekends 1500 East Medical Center Drive, Ann Arbor, (734) 936-6666

Spill Procedure

• When a spill occurs, personal safety should always come first.

• Alert and clear everyone in the immediate area where the spill occurred.

• Use proper personal protective equipment (PPE) as noted above.

A minor (small) chemical spill is one that the laboratory staff is capable of handling safely without the assistance of safety and emergency personnel, i.e., less than 1 Gallon or 3.5 Liters. A major/large chemical spill requires active assistance from emergency personnel.

Spill Response Steps:


• Alert people in immediate area of spill.

• Open outside windows, if possible.

• Use proper personal protective equipment as indicated above.

• Avoid breathing vapors from spill.

• Confine spill to as small an area as possible.

• Do not wash spill down the drain.

• Use appropriate spill kits/sorbents to absorb spill. Collect contaminated materials and residues and place in container. Contact OSEH-HMM (734) 763-4568 for proper disposal.

• Clean spill area with water.


 Report large chemical spills greater than 1 Gallon or 3.5 Liters in corridors or common areas, e.g., hallways, elevators, eating areas, rest rooms, offices, etc., to U-M Division of Public Safety and Security (DPSS) by calling 911.

• Attend to injured or contaminated persons and remove them from exposure.

• Alert people in the laboratory to evacuate.

• Call U-M Division of Public Safety and Security (DPSS) at 911 immediately for assistance.

• Close doors to affected area.

• Post warnings to keep people from entering the area.

• Have person available that has knowledge of incident and laboratory to assist emergency personnel.

Additional Spill Links: •

 Report all emergencies, suspicious activity, injuries, spills, and fires to the University of Michigan Division of Public Safety and Security (DPSS) by calling 911 or texting 377911. Register with the University of Michigan Emergency Alert System via Wolverine Access.

Training of Personnel

All personnel are required to complete the General Laboratory Safety Training session (BLS025w or equivalent) via OSEH’s My LINC website. Furthermore, all personnel shall read and fully adhere to this SOP when handling chloroform.


I have read and understand the above SOP. I agree to contact my Supervisor or Lab manager if I plan to modify this procedure.

Prior Approval required – Is this procedure hazardous enough to warrant prior approval from the Laboratory Director? ☐ YES ☐ NO

Laboratory Director Revision Date � Major Revisions (Tracking purposes only – Do not print as part of SOP) 8-26-2016 Added details on phosgene generation, expiration based on stabilizer, updated glove