1. OSHA Occupational Chemical Database
  2. METHYL IODIDE
Label abbreviations descriptions

METHYL IODIDE†

Chemical Identification
Chemical Identification
CAS # 74-88-4
Formula
 

CH₃I
Synonyms
 

iodomethane; monoiodomethane
Physical Properties
Physical Properties
Physical description Colorless liquid with a pungent, ether-like odor.
Boiling point 109°F Molecular weight 141.94
Freezing point/melting point -88°F Vapor pressure 400 mmHg
Flash point Vapor density
Specific gravity 2.28 Ionization potential 9.54 eV
Lower explosive limit (LEL) 10% Upper explosive limit (UEL) 15%
NFPA health rating 3 NFPA fire rating 0
NFPA reactivity rating 0 NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs
Monitoring Methods Used by OSHA
Monitoring Methods Used by OSHA
Analyte code (IMIS no.) 1772
Sampling group
Sampler/Sampling media CSC tube (100/50 mg) [SKC 226-01]
Sampling time*
 

 
Sampling volume (TWA)*
 

15-50 L
Sampling flow rate (TWA)*
 

0.01-1 L/min
Sampling volume (STEL/Peak/C)*
 

 
Sampling flow rate (STEL/Peak/C)*
 

 
Analytical method instruments GC-FID
Method reference NIOSH 1014 (partially validated)
Notes
 

 
Special requirements
 

 

* All sampling instructions above are recommended guidelines for OSHA Compliance Safety and Health Officers (CSHOs), please see the corresponding OSHA method reference for complete details.

Wipe Method
Wipe Method
Sampler/Sampling media
 

 
Bulk Method
Bulk Method
 

 
On-Site Screening Techniques
On-Site Screening Techniques
Device Infrared spectrophotometer Detector tube
Model/Type Miran 1A & 1B Matheson-Kitagawa 8014-176S
Sampling information
(see manufacturer instructions) 		1.8 ppm@3.4µm 5-40 ppm range
Exposure Limits
Exposure Limits
OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
NIOSH REL
Up to 10-hour TWA
(ST) STEL
(C) Ceiling
ACGIH TLV©
8-hour TWA
(ST) STEL
(C) Ceiling
CAL/OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
PEL-TWA
 

5 ppm (28 mg/m³)

 REL-TWA
 

2 ppm (10 mg/m³)

 TLV-TWA
 

2 ppm [1978]

 PEL-TWA
 

2 ppm (10 mg/m³)
PEL-STEL
 

 

 REL-STEL
 

 

 TLV-STEL
 

 

 PEL-STEL
 

 
PEL-C
 

 

 REL-C
 

 

 TLV-C
 

 

 PEL-C
 

 
Skin notation
 

Y

 Skin notation
 

Y

 Skin notation
 

Y

 Skin notation
 

Y
Notes:
 

See 29 CFR 1910.1000 Table Z-1.

 Notes:
 

CARCINOGEN (Ca): REDUCE EXPOSURE TO LOWEST FEASIBLE CONCENTRATION (LOQ 1.7 ppm). See Appendix A, NIOSH Potential Occupational Carcinogens.

 Notes:
 

 

 Notes:
 

 
Health factors:  See NIH-NLM PubChem. IDLH
 

100 ppm
Carcinogenic classifications: IARC-3, NIOSH-Ca Notes:
 

Ca
AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:
 

25 ppm/50 ppm/125 ppm
Additional Resources and Literature References
Additional Resources and Literature References

NOAA: CAMEO Chemicals - Methyl iodide

NIOSH: Pocket Guide to Chemical Hazards - Methyl iodide

Literature References

 
  • ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Methyl iodide. See annual publication for most recent information.

Last Updated Date : 01/29/2021