2-BUTANONE (METHYL ETHYL KETONE; MEK)†

Chemical Identification
Chemical Identification
CAS # 78-93-3
Formula

C₄H₈O

Synonyms

ethyl methyl ketone; MEK; methyl acetone; methyl ethyl ketone

Physical Properties
Physical Properties
Physical description Colorless liquid with a moderately sharp, fragrant, mint- or acetone-like odor.
Boiling point 175°F Molecular weight 72.1
Freezing point/melting point -123°F Vapor pressure 78 mmHg
Flash point 16°F Vapor density 2.42
Specific gravity 0.81 Ionization potential 9.54 eV
Lower explosive limit (LEL) 1.4% at 200°F Upper explosive limit (UEL) 11.4% at 200°F
NFPA health rating 1 NFPA fire rating 3
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.) 0430
Sampling group
Sampler/Sampling media SKC 575-002 Passive Sampler [SKC 575-002]
Sampling time*

240 min

Sampling volume (TWA)*
Sampling flow rate (TWA)*
Sampling volume (STEL/Peak/C)*
Sampling flow rate (STEL/Peak/C)*
Analytical method instruments GC-FID
Method reference OSHA 1004 (fully validated)
Notes

In order to obtain defensible and quantitative results for MEK, sampling must be done with the passive sampler. To obtain sampling and analytical error similar to that available with active sampling, knowledge of the atmospheric pressure and temperature are required, and these should be obtained using NIST-traceable devices.

If that is not possible, temperature is assumed to be 22.2 °C, and the atmospheric pressure is estimated based on the elevation of the sampling location.

When estimates are used in place of traceable measurements the sampling and analytical error associated with passive sampling is substantially increased, and this makes it more difficult to demonstrate overexposures after considering the 95% lower confidence limit.

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
Model/Type
Sampling information
(see manufacturer instructions)
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
 

200 ppm (590 mg/m³)

REL-TWA
 

200 ppm (500 mg/m³)

TLV-TWA
 

200 ppm [1992]

PEL-TWA
 

200 ppm (590 mg/m³)

PEL-STEL
 

 

REL-STEL
 

300 ppm (885 mg/m³)

TLV-STEL
 

300 ppm [1992]

PEL-STEL
 

300 ppm (885 mg/m³)

PEL-C
 

 

REL-C
 

 

TLV-C
 

 

PEL-C
 

 

Skin notation
 

N

Skin notation
 

N

Skin notation
 

N

Skin notation
 

N

Notes:
 

See 29 CFR 1910.1000 Table Z-1.

Notes:
 

 

Notes:
 

BEI®

Notes:
 

 

Health factors:  See NIH-NLM PubChem. IDLH
 

3000 ppm 

Carcinogenic classifications: Not listed Notes:
 

 

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

 

Additional Resources and Literature References
Additional Resources and Literature References

NOAA: CAMEO Chemicals - Methyl ethyl ketone

NIOSH: Pocket Guide to Chemical Hazards - 2-Butanone

Literature References

 
  • ACGIH: Documentation of the Threshold Limit Values (TLVs) and Biological Exposure Indices (BEIs) - Methyl Ethyl Ketone. See annual publication for most recent information.
  • EPA: Integrated Risk Information System - Methyl ethyl ketone (MEK) (CASRN 78-93-3). September 2003a.
  • EPA: Toxicological Review of Methyl Ethyl Ketone (CAS No. 78-93-3). September 2003b.
  • NIOSH: Criteria for a Recommended Standard - Occupational Exposure to Ketones. 1978.
  • NIOSH: Occupational Safety and Health Guideline for 2-Butanone. 1988.
  • Pohanish, R.P. (editor): Methyl ethyl ketone. In: Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 2. Norwich, NY: Noyes Publications, William Andrew Publishing, pp. 1566-1568, 2002.
  • Tomicic, C, Berode, M, Oppliger, A, Castella, V, Leyvraz, F, Praz-Christinaz, SM, Danuser, B: Sex differences in urinary levels of several biological indicators of exposure - a human volunteer study. Toxicol Lett. 202(3):218-25, May 10, 2011.

Last Updated Date : 12/15/2020