UN Number: 1978 - CAS Number: 74-98-6

Also known as: Dimethylmethane, Propyl Hydride, Propane
Information on chemical

Information on chemical

External resources

CAMEO Chemical Database
WISER Substance List


UN number 1978
CAS number 74-98-6
Formula C3H8

Physical chemical data

Physical State (20°C) Gas
Physical State (25°C) Gas
Density (kg/m3)
2.012 [Kg/m³] at a temperature of 20°C
493 [Kg/m³] at a temperature of 25°C
Molar mass (g/mol) 44.09
Density of gas (kg/m3) 2.012
Solubility (g/L)
70 [g/L] at a temperature of 20°C and salinity of 0‰
Boiling Point (°C) -41.9
Melting Point (°C) -186
Critical temperature (°C) 369.89
Critical pressure (Pa) 4215000
Surface tension (mN/m)
16 [mN/m] at a temperature of -47°C
Interfacial tension (mN/m)
50 [mN/m] at a temperature of -50°C and salinity of 0‰
Vapour Pressure (Pa)
861050 [Pa] at a temperature of 20°C
953260 [Pa] at a temperature of 25°C
Vapour pressure at 70% of critical temperature (Pa) 299030
Ignition Temperature (°C) 470
Flash Point (°C) -42
Flash Point (Pensky-Martens closed cup) (°C) -104
Lower explosivity limit (LEL) (volume %) 2.2
Upper explosivity limit (UEL) (volume %) 9.5
Vapor enthalpy (J/Kg)
3353741 [J/Kg] at a temperature of 25°C
Henry's constant (mol/(m³·Pa)) 71636.775

Behaviour at sea

Log kow 2.36
Log koc 1.33
Aqueous photolysis (Half-life) Not photolysable
Biodegradation in estuary environment (Half-life) (days) Not hydrolysable
Bioconcentration factor (BCF) 13

Additional data

Colour colourless
Odour odourless
MARPOL pollution category
Category Description
Other Substances Substances which have been evaluated and found to fall outside Category X, Y or Z because they are considered to present no harm to marine resources, human health, amenities or other legitimate uses of the sea when discharged into the sea from tank cleaning of deballasting operations. The discharge of bilge or ballast water or other residues or mixtures containing these substances are not subject to any requirements of MARPOL Annex II.

Transportation data

Transport mode Gas,Packaged
Ship type 2G,2PG
Cargo group 31
State liq.compr.gas
Temperature (°C) ambient
Pressure (Pa) under pressure
Family name paraffins
IMO class 2(2.1)

Reactivity data

Water No
Static electricity Yes

GESAMP Hazard profile

Interference with coastal amenities (E2) G - Gas

Human toxicity threshold

Compressed Gas Flammable
IDHL 20000
Hazard statements
H220 Extremely flammable gas.
TLV-TWA 1000
TEEL-1 (mg/m3) 5500 ppm
TEEL-2 (mg/m3) 17000 ppm
TEEL-3 (mg/m3) 33000 ppm


Lowest median lethal concentration (LC50) on crustacean (mg/l) 69.43
Lowest median lethal concentration (LC50) on fishes (mg/l) 49.9
Incident reports

Incident reports

Year Vessel Location Cargo type
1974 Yuyo Maru Nº 10 Tokyo Bay, Japan Bulk
Emergency Response Guidebook

Emergency Response Guidebook

Guide number: 115

See the guide or download the emergency response guidebook

At sea emergency guide

At sea emergency guide

Emergency schedule: 2-07


Emergency procedures


Avoid all skin contact.
Avoid all sources of ignition (e.g. naked lights, unprotected light bulbs, electric handtools).

Spillage on deck

Stop leak if practicable. Let spilt liquid evaporate.

Spillage under deck

Provide adequate ventilation. Stop leak if practicable. Let spilt liquid evaporate.

Fire on deck

Use water spray, foam or dry chemical from as far away as practicable.
Keep adjacent receptacles cool with copious quantities of water. Remove undamaged cooled receptacles to a safe place.

Fire under deck

Batten down; use ship's fixed fire-fighting installation. Otherwise adopt action as for "On deck".

Special equipment to be carried

Protective gloves.
Self-contained breathing apparatus.
Spray nozzles.

Remarks by UN no.

Care! Heated receptacles should be jettisoned as possible explosion hazard.

Decision trees

Decision trees

No decision trees available

No additional data

last modified 2023-01-30T09:54:33+00:00

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