Standard Operating Procedure for Chloroform (Methylidyne Trichloride, Trichloromethane)


University of North Carolina at Chapel Hill Standard Operating Procedure for Chloroform (Methylidyne Trichloride, Trichloromethane)

EHS SOP #: 010

Version No.: 2.0

Supercedes: N/A

Chloroform Formula


Chloroform (CAS 67-66-3) is commonly used in laboratories during DNA purification procedures in biology and biochemistry. It is also used as a solvent in synthetic chemistry. Chloroform is a clear, colorless, nonflammable, volatile liquid with a pleasant sweet odor. This document establishes procedures for the safe handling and use of chloroform.

Health Effects

Chloroform is a suspect carcinogen (IARC Group 2B) which can cause adverse health effects to the cardiovascular system, central nervous system, blood, liver, kidney and nerves. It is an eye, skin and respiratory tract irritant. It is readily absorbed into the skin. When heated or exposed to fire, chloroform generates toxic gases such as phosgene and chlorine. It is also suspected to be a reproductive and developmental hazard. Pregnant women or those who may become pregnant should not be exposed to or handle this chemical in any form.

Acute exposure

Inhalation of vapors can cause headaches, drowsiness, dizziness, and nausea. Disorientation, anesthetic effects, and loss of consciousness can occur at high concentrations. Skin and eye exposure will result in irritation

Chronic exposure

Kidney, liver, circulatory system, and central nervous system (brain) damage may occur.

Regulatory Limits

The Federal Occupational Safety and Health Administration (OSHA) Permissible Exposure Limit (PEL) for chloroform is 50 ppm (244.13 mg/m3) as a ceiling limit (exposure must never exceed this level). The American Conference of Governmental Industrial Hygienists (ACGIH) has a threshold limit value (TLV) for chloroform of 10 ppm (48.83 mg/m3) for an 8-hour workday. The National Institute of Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) is set at 2 ppm (9.78 mg/m3) as a 60-minute Short Term Exposure Limit (STEL).

The odor threshold for chloroform is 85ppm(415.02 mg/m3)1 (above OSHA’s ceiling limit), so it does not have good warning properties. Aside from a high odor threshold, Chloroform also fatigues the olfactory system through continued exposure by inhalation. This reduces the nose’s ability to detect chloroform, which would increase the ppm of chloroform in the air needed to detect the chemical.

Air Monitoring

  • Area monitoring can be requested to assess potential exposures in the general laboratory work area. The monitoring is performed using a direct read instrument to give concentrations in room during procedures.
  • Personal monitoring can be requested to determine potential exposures for individual employees who work with chloroform. The monitoring is performed using a passive dosimeter that the employee wears in their breathing zone to quantify potential exposure.
  • Exposure monitoring can be requested by contacting Environment, Health & Safety (EHS) at: 919-962-5507.


Based on the risk associated with the use of chloroform, the safety procedures outlined below are required by all research staff when working with chloroform.

Administrative Controls

  • Anyone who handles chloroform is required to review this SOP and the attached Safety Data Sheet (SDS) prior to work.
  • An emergency eyewash station should be located inside lab spaces and a safety shower should be accessible nearby where chloroform and chloroform solutions are handled.
  • Containers of chloroform should be kept closed at all times unless actively dispensing.
  • Areas where chloroform is prepared and/or administered should be cleaned immediately following each task. The affected area should be decontaminated three times with towels moistened with water.
  • Users of chloroform should wash their hands thoroughly with soap and water after handling and use.
  • Pregnant females should consult their primary care physician before handling.
  • Use the smallest practical quantities for the experiment that is being performed and minimize all chloroform contact with gloved hands.

Engineering Controls

  • All operations involving handling chloroform must be conducted in a properly operating chemical fume hood.

Personal Protective Equipment (PPE)

  • Acceptable gloves2,3:
    • Extra thick nitrile gloves (8 mil) or double standard nitrile gloves (2 x 4 mil). If
      double gloved, remove outer glove if contamination occurs and replace with new
    • Viton
    • Polyvinyl acetate (PVA)
    • Vitoject: flourinated rubber, 0.7 mm thickness
  • Lab coat
  • Safety glasses or goggles
  • Face guard with splash goggles and impervious apron, if a splash may occur

Waste Disposal

  • Used and unused solutions containing chloroform will be disposed of as a hazardous material through EHS.

Accidents or Injuries

  • If chloroform is splashed on an individual or in eyes flush for 15 minutes with copious quantities of water and contact the University Employee Occupational Health Clinic (919-966-9119).
  • If chloroform exposure is via inhalation, move exposed worker to fresh air, and contact the University Employee Occupational Health Clinic (919-966-9119).

Spill Procedures

  • Do not attempt to clean-up if you feel unsure of your ability to do so or if you perceive the risk to be greater than normal laboratory operations.
  • If a small spill occurs absorb with absorbent pads. Double bag contaminated solid waste and submit for EHS hazardous material pickup.
  • If a large spill occurs notify others in the area and evacuate room immediately. Contact EHS (919-962-5507) during working hours and 911 if after hours.

Contact Information

Policy Contact

Environment, Health & Safety
1120 Estes Drive
Campus Box #1650
Chapel Hill, NC 27599-1650
Phone: 919-962-5507


1. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Chloroform. Public Health Service, U.S. Department of Health and Human Services, Atlanta, GA. 1997.

2. Sigma-Aldrich Chloroform SDS, version 4.12 (see attached PDF).

3. Lawrence Berkley National Laboratory (U.S. Department of Energy): Chemical Resistance of Gloves - Quick Guide.

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Article ID: 132069
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