METHYL ACETYLENE (PROPYNE)†

Chemical Identification

CAS # 74-99-7
Formula
 

C₃H₄

Synonyms
 

allylene; propine; propyne; 1-propyne

Physical Properties

Physical description Colorless gas with a sweet odor.
Boiling point -10°F Molecular weight 40.1
Freezing point/melting point -153°F Vapor pressure 5.2 atm
Flash point Vapor density 1.41
Specific gravity Ionization potential 10.36 eV
Lower explosive limit (LEL) 1.7% Upper explosive limit (UEL)
NFPA health rating 1 NFPA fire rating 4
NFPA reactivity rating 3 NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs

Monitoring Methods Used by OSHA

Analyte code (IMIS no.)
Sampling group
Sampler/Sampling media
Sampling time*
Sampling volume (TWA)*
Sampling flow rate (TWA)*
Sampling volume (STEL/Peak/C)*
Sampling flow rate (STEL/Peak/C)*
Analytical method instruments
Method reference
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.

Bulk/Wipe Method

Wipe Sampler/Sampling media
 

 

Bulk Method

On-Site Screening Techniques

Device Infrared spectrophotometer
Model/Type Miran 1A & 1B
Sampling information
(see manufacturer instructions)
2.8 ppm@3.0 µm

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

1000 ppm (1650 mg/m³)

REL-TWA
 

1000 ppm (1650 mg/m³)

TLV-TWA
 

1000 ppm (EX) [1956]

PEL-TWA
 

1000 ppm (1650 mg/m³)

PEL-STEL REL-STEL
 

 

TLV-STEL
 

 

PEL-STEL
 

 

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:
 

(EX) explosion hazard: the substance is a flammable asphyxiant or excursions above the TLV could approach 10% of the lower explosive limit.

Notes:
 

 

Health factors:  See NIH-NLM PubChem. IDLH
 

1700 ppm

Carcinogenic classifications: Not listed Notes:
 

10% of LEL

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

 

Additional Resources and Literature References

Last Updated Date : 01/05/2021