Label abbreviations descriptions

HEXONE (METHYL ISOBUTYL KETONE; MIBK)†

Chemical Identification
CAS # 108-10-1
Formula
 

C₆H₁₂O
Synonyms
 

isobutyl methyl ketone; methyl isobutyl ketone; 4-methyl 2-pentanone; MIBK

Physical Properties
Physical description Colorless liquid with a pleasant odor.
Boiling point 242°F Molecular weight 100.16
Freezing point/melting point -120.5°F Vapor pressure 16 mmHg
Flash point 73°F Vapor density 3.45
Specific gravity 0.8 Ionization potential 9.30 eV
Lower explosive limit (LEL) 1.4% Upper explosive limit (UEL) 7.5%
NFPA health rating 2 NFPA fire rating 3
NFPA reactivity rating 1 NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs

Monitoring Methods Used by OSHA
Analyte code (IMIS no.) 1385 1385
Sampling group OVSG-4
Sampler/Sampling media Two 600mg silica gel tubes connected in series [SKC 226-183]; tube holder [SKC 222-3L-1]; Type D cover [SKC 224-29D] SKC 575-002 Passive Sampler [SKC 575-002]
Sampling time*

120 min
 

240 min
Sampling volume (TWA)*

6 L
 

 
Sampling flow rate (TWA)*
 

 
Sampling volume (STEL/Peak/C)*
 

 
Sampling flow rate (STEL/Peak/C)*
 

 
Analytical method instruments GC-FID
Method reference OSHA 5004 (fully validated) OSHA 1004 (fully validated)
Notes
 

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.

Bulk/Wipe Method
Wipe Sampler/Sampling media
 

 
Bulk Method
 

 

On-Site Screening Techniques
Device
Model/Type
Sampling information
(see manufacturer instructions)

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
 

100 ppm (410 mg/m³)

 REL-TWA
 

50 ppm (205 mg/m³)

 TLV-TWA PEL-TWA
 

50 ppm (205 mg/m³)
PEL-STEL
 

 

 REL-STEL
 

75 ppm (300 mg/m³)

 TLV-STEL PEL-STEL
 

75 ppm (300 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:
 

Visit the ACGIH TLV site for specific data
BEI®

 Notes:
 

 
Health factors:  See NIH-NLM PubChem. IDLH
 

500 ppm
Carcinogenic classifications: EPA-1, TLV-A3 Notes:
 

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

 

Additional Resources and Literature References

Last Updated Date : 05/05/2025