Liquid cargo of the month December 2025 – Isoprene

Trade name/synonym name 2-methyl-1,3-Butadiene; Isopentadiene; Hemiterpene; beta-Methylbivenyl; Isopren. 

Main Properties  

Isoprene is a colourless liquid with an aromatic odour 

Isoprene is extremely flammable and highly reactive. This means that it can burn explosively and can also spontaneously” polymerise”. The boiling point of Isoprene is only 34 deg. C and therefore, this cargo is often cooled during transport. 

 Main chemical and physical properties:  

Flash point Minus 48 deg. C 

Boiling Points 34 deg. C 

Viscosity @ 20°C < 50 mPa.s 

Vapour pressure @ 20°C > 5 kPa (suitable for ventilation) 

Density 680 kg/m3 @ 20 deg. C 

IBC carriage requirements:  

IBC chapter 17 

Ship Type 2 

Tank Type 2G 

Relevant additional IBC requirements:  

15.12 Toxic products. Requirements to exhaust openings of vent systems. Connection for vapour-return line to the shore installation. Not to be stowed adjacent to oil fuel tanks. Separate piping systems. Cargo tank relief-valve setting minimum 0.02 MPa gauge (= 200 mBar) 

15.13 cargoes protected by additives (inhibitor) 

15.14 cargoes with high vapour pressure: A mechanical refrigeration system shall be available unless the tank can withstand tank pressure at 45 deg. C. Administration may waive requirements for a refrigeration system on special voyages. Vapour return to shore during loading. Calculate maximum filling level 

15.19.6 high-level alarm 

16.6.1 and 16.6.2 cargoes not to be exposed to excessive heat. No heat adjacent. Heating coils shall be blanked off 

“T” an instrument or detector tubes for detection of toxic cargo vapours shall be on board. 

 MARPOL Requirements:  

Annex II 

Pollution Category Y 

Special information to be added to Shipping Document - No special information to be added to shipping document. 

However, IBC 15.13.3 requires the vessel to be provided with a certificate of protection (inhibition) from the manufacturer of the cargo. 

Stowage:  

Heat adjacent No 

Stow adjacent to fuel oil tanks No. 

Carriage requirements  

Heating during voyage No 

Heating coils in cargo tanks shall be blanked off 

Heating during unloading No 

Tanks inerted or padded  - Not required by IBC code. However, this cargo is always loaded into nitrogen purged tanks and oxygen content during transport is typically less than 0.5 % 

Prewash required? No. 

Tank cleaning: 

This cargo has a very high vapour pressure at ambient temperature 

As Isoprene is inhibited to prevent polymerization, heat should be avoided during tank cleaning if cargo residues remain in tanks, pumps and cargo piping 

Flush the lines and tank bottom with ambient temperature water to remove the inhibited cargo residues 

Warm temperature water wash 

Ambient temperature freshwater rinse 

In order to remove inhibitor from tank surfaces it may be necessary to recirculate with moderate temperature water added suitable cleaning additive. 

Emergency Response:  

Fire: Use foam or water spray - not water jet 

Spillage: Eliminate sources of ignition. Collect small spills with absorbent material. Larger spills: Try to collect and transfer to spill tank or wash away with water. When in port, - inform Port Authority 

First aid: Remove victim to fresh air. Follow first aid instructions in MSDS. Consider obtaining advice from Radio Medical. 

Hazards (Occupational safety etc):  

Very volatile product.  

Prolonged contact with the substance can cause irritant effects to skin and eyes and inhaling it in high concentrations can cause dizziness and headache. Isoprene is classified as a possible human carcinogen 

“T” an instrument or detector tubes for detection of toxic cargo vapours shall be on board 

TLV: 2 ppm. 

Precautions:  

Expect cargo tank wall wash before loading 

Isoprene is liable to polymerization. Ensure certificate of inhibition is on board before loading. Check whether the added inhibitor is oxygen dependant 

Not to be stowed adjacent to heated tanks. Adjacent tank temperature should not be higher than 20 deg. C. 

Remarks:  

Use: The polymerisation of isoprene using catalysts yields a synthetic rubber, polyisoprene, which closely resembles natural rubber. Polyisoprene is used in a wide variety of rubber applications including medical equipment, baby bottle teats/nipples, toys, shoe soles, tyres, and elastic films and threads for golf balls or textiles. It is also used in adhesives and in paints and coatings. Butyl rubber, made from isobutene with a small amount of isoprene has outstanding impermeability to gases and is used, for example, in inner tubes. Styreneisoprene-rubber is a copolymer that is used in pressure sensitive adhesives. 

The BIMCO Liquid Cargo Database contains information for more than 360 cargoes, all updated to the IBC Code 2021 amended requirements, but in order to ensure that the BIMCO Liquid Cargo Database information is kept updated, we highly welcome any feedback in the form of comments, response, information or data regarding a specific cargo.