US Dept of Labor

Occupational Safety & Health AdministrationWe Can Help


General Description

  • Synonyms: Trichloromethane
  • OSHA IMIS Code Number: 0670
  • Chemical Abstracts Service (CAS) Registry Number: 67-66-3
  • NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: FS9100000
  • Department of Transportation Regulation Number (49 CFR 172.101) and Emergency Response Guidebook: 1888 151
  • NIOSH Pocket Guide to Chemical Hazards, Chloroform: chemical description, physical properties, potentially hazardous incompatibilities, and more

Exposure Limits

  • OSHA Permissible Exposure Limit (PEL):
  • American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Value (TLV): 10 ppm, 49mg/m3 TWA; Appendix A3 - Confirmed Animal Carcinogen with Unknown Relevance to Humans
  • National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL): 2 ppm, 9.78mg/m3 STEL (60 Minutes); Appendix A - NIOSH Potential Occupational Carcinogens

Health Factors

  • Carcinogenic Classification:
  • NIOSH Immediately Dangerous To Life or Health Concentration (IDLH): 500 ppm
  • Potential Symptoms: Dizziness, mental dullness, irritability, confusion, distorted perceptions; loss of appetite, nausea; headaches; fatigue; anesthesia; hepatomegaly, hepatitis, jaundice; eye irritation (tearing, conjunctivitis, permanent eye damage), skin irritation (drying, cracking, redness, dermatitis, pain); [potential occupational carcinogen] Ingestion Acute: abdominal pain, vomiting
  • Health Effects: Cumulative liver and kidney damage (HE3); Known animal and suspected human carcinogen (HE2); Narcosis (HE8)
  • Affected Organs: Liver, kidneys, heart, eyes, skin, CNS
  • Notes:
    1. The odor threshold of chloroform (85 ppm) is greater than its PEL.
    2. Metabolized to the toxic reactive metabolite, phosgene, by the CYP2E1 and CYP2A6 isozymes of cytochrome P450, with a higher affinity for CYP2E1, an enzyme induced in the liver by chronic ethanol consumption.
  • Literature Basis:
    • NIOSH Pocket Guide to Chemical Hazards: Chloroform.
    • International Chemical Safety Cards (WHO/IPCS/ILO): Chloroform.
    • EPA Air Toxics Website: Chloroform. U.S. Environmental Protection Agency Technology Transfer Network.
    • Gemma, S., Vittozzi, L. and Testai, E.: Metabolism of chloroform in the human liver and identification of the competent P450s. Drug Metab. Dispos. 31(3): 266-274, 2003.
    • Pohanish, R.P. (editor): Chloroform. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 568-571.
  • Date Last Revised: 01/05/2004

Monitoring Methods used by OSHA

Laboratory Sampling/Analytical Method:
  • Charcoal Tube (100/50 mg sections, 20/40 mesh)
  • maximum volume: 10 Liters
  • maximum flow rate: 0.2 L/min (TWA)
  • maximum volume: 15 Liters
  • maximum flow rate: 0.2 L/min (Ceiling)
  • current analytical method: Gas Chromatography; GC/FID
  • analytical solvent: Carbon disulfide
  • alternative solvent: (99:1) Carbon disulfide/Dimethylformamide
  • method reference: OSHA Manual of Analytical Methods (OSHA 5)
  • method classification: Fully Validated
On-Site Sampling Techniques/Methods:
  • Detector Tube
  • manufacturer: AUER/MSA
  • model/type: Trichloroethane-5, MSA P/N 487343, AUER P/N 5086-834
  • sampling information: follow manufacturer's instructions
  • upper measurement limit: 100 ppm
  • detection limit: approximately 8 ppm
  • overall uncertainty: unknown
  • method reference: on-site air secondary (manufacturer)
  • Detector Tube
  • manufacturer: Dräger
  • model/type: Chloroform 2/a, order no. 67 28861
  • sampling information: 10 strokes
  • upper measurement limit: 10 ppm
  • detection limit: approximately 1 ppm
  • overall uncertainty: approximately 33%
  • method reference: on-site air secondary (manufacturer)
  • Detector Tube
  • manufacturer: Gastec
  • model/type: 137L
  • sampling information: 3 or 5 strokes
  • upper measurement limit: 27 ppm
  • detection limit: 0.1 ppm
  • overall uncertainty: 16% for 0.5 to 2 ppm, 8% for 2 to 10 ppm
  • method reference: on-site air secondary (manufacturer)
  • Detector Tube
  • manufacturer: Matheson-Kitagawa
  • model/type: 8014-152S
  • sampling information: 2 or 4 strokes
  • upper measurement limit: 500 ppm
  • detection limit: approximately 20 ppm
  • overall uncertainty: unknown
  • method reference: on-site air secondary (manufacturer)

** All Trademarks are the property of their respective owners.

Search Chemical Sampling Information


By Name


By CAS Number
collage image - OSHA Salt Lake Technical Center

*Accessibility Assistance: Contact OSHA's Directorate of Technical Support and Emergency Management at (202) 693-2300 for assistance accessing PDF materials.

All other documents, that are not PDF materials or formatted for the web, are available as Microsoft Office® formats and videos and are noted accordingly. If additional assistance is needed with reading, reviewing or accessing these documents or any figures and illustrations, please also contact OSHA's Directorate of Technical Support and Emergency Management at (202) 693-2300.

**eBooks - EPUB is the most common format for e-Books. If you use a Sony Reader, a Nook, or an iPad you can download the EPUB file format. If you use a Kindle, you can download the MOBI file format.

Back to Top

Thank You for Visiting Our Website

You are exiting the Department of Labor's Web server.

The Department of Labor does not endorse, takes no responsibility for, and exercises no control over the linked organization or its views, or contents, nor does it vouch for the accuracy or accessibility of the information contained on the destination server. The Department of Labor also cannot authorize the use of copyrighted materials contained in linked Web sites. Users must request such authorization from the sponsor of the linked Web site. Thank you for visiting our site. Please click the button below to continue.