Skip to content

Chemical collection and stock control for UK schools, universities and hospitals

Isopentane (CAS 78-78-4): storage and disposal

Isopentane, also sold as 2-methylbutane, is held in university and histology labs for tissue freezing. It is classed as extremely flammable, may be fatal if swallowed and enters airways, can cause drowsiness and dizziness, and is toxic to aquatic life with long lasting effects. It is not stored like ordinary solvents, because its extreme flammability sets it apart from most bottles in a research or hospital histology room.

CAS number
78-78-4
Form
Liquid
Storage class
Flammable
Signal word
Danger
Usual EWC code
16 05 06*
  • Flammable pictogramFlammable
  • Harmful or irritant pictogramHarmful or irritant
  • Serious health hazard pictogramSerious health hazard
  • Hazardous to the environment pictogramHazardous to the environment

What to do this week

  1. Check the label is readable and write down the opened date if it is not already there.
  2. Check it is stored as flammable stock and apart from the items listed under "Do not store with".
  3. If you no longer need it, add it to your disposal list so it goes on the next collection.

Safe storage in a school or lab

Extreme flammability decides where isopentane goes, which is the ventilated flammables cabinet with spill containment and no ignition source anywhere near. Keep it apart from oxidisers, oxidising acids and corrosives, which can ignite it or break down its container. In a cryostat room the working bottle often stands near the freezing bath and dry ice supply, so keep the main stock back in the cabinet and bring out only what a run needs. Only a spark-free refrigerator or freezer should ever hold it. Label bottles with the name isopentane or methylbutane consistently.

How to tell it has deteriorated

No characteristic colour or crystal change marks its age, so a technician checks the bottle and the bath. Look for a lowered level, a hissing or bulging cap from vapour pressure and a label that has lost its writing. Fluid taken from a freezing bath may carry tissue fragments and frost, which turns it from clean stock into used waste. Two names are in use for the same liquid, so an unlabelled or relabelled bottle can look like a second product when it is not. Leave any bulging bottle upright and cool for the collector.

How it must be disposed of

By specialist collection only. It never goes down the drain or into general waste. It is normally packed in a flammable laboratory pack with compatible chemicals.

Used bath fluid is not the same description as clean bottles, so record which is which. Specialist collection is the only route, with isopentane grouped with compatible flammable organics. It must not be poured away, evaporated or left in an open dish at the end of a run. A university lab can use 16 05 06*, a loose organic chemical not in a pack takes 16 05 08*, and a hospital histology unit can use 18 01 06*. Tell the collector about extreme flammability when booking so that the bottles are handled accordingly.

Waste codes and transport details for Isopentane
EWC code, laboratory chemicals16 05 06*
Discarded organic chemical, not a laboratory pack16 05 08*
Human healthcare setting18 01 06*
Hazardous wasteYes

20 01 13* (solvents) belongs to municipal collections and is shown for reference only. It is not the normal code for a laboratory collection.

The code depends on where the waste came from and what it is mixed with. Use the waste code finder to see why.

Do not store with

  • OxidiserOxidisers can ignite flammable materials or make a fire far more intense.
  • AcidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • CorrosiveA leak of corrosive stock can break down flammable containers and feed a fire.

Named chemicals to keep apart

  • Acetic acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Calcium hypochloriteOxidisers can ignite flammable materials or make a fire far more intense.
  • Hydrochloric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Hydrogen peroxideOxidisers can ignite flammable materials or make a fire far more intense.
  • Nitric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
  • Potassium nitrateOxidisers can ignite flammable materials or make a fire far more intense.
  • Potassium permanganateOxidisers can ignite flammable materials or make a fire far more intense.
  • Sulfuric acidOxidising acids can ignite flammable materials, and acid fumes attack containers and seals.
Show 2 more
  • Thionyl chlorideA leak of corrosive stock can break down flammable containers and feed a fire.
  • Zinc chlorideA leak of corrosive stock can break down flammable containers and feed a fire.

Common quantities we collect

Usually held as: neat, tissue freezing.

Part-used bottles and full containers are both fine. Tell us the size and how many, and an estimate is enough for a first price.

Where it is commonly held

Hazard statements

  • H224 Extremely flammable liquid and vapour.
  • H304 May be fatal if swallowed and enters airways.
  • H336 May cause drowsiness or dizziness.
  • H411 Toxic to aquatic life with long lasting effects.
Precautionary statements
  • P210 Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P233 Keep container tightly closed.
  • P240 Ground and bond container and receiving equipment.
  • P241 Use explosion-proof electrical, ventilating and lighting equipment.
  • P242 Use non-sparking tools.
  • P243 Take action to prevent static discharges.
  • P261 Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P271 Use only outdoors or in a well-ventilated area.
  • P273 Avoid release to the environment.
  • P280 Wear protective gloves, protective clothing, eye protection and face protection.
  • P301+P316 IF SWALLOWED: Get emergency medical help immediately.
  • P303+P361+P353 IF ON SKIN (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower.
  • P304+P340 IF INHALED: Remove person to fresh air and keep comfortable for breathing.
  • P319 Get medical help if you feel unwell.
  • P331 Do NOT induce vomiting.
  • P370+P378 In case of fire: Use suitable extinguishing media to extinguish.
  • P391 Collect spillage.
  • P403+P233 Store in a well-ventilated place. Keep container tightly closed.
  • P403+P235 Store in a well-ventilated place. Keep cool.
  • P405 Store locked up.
  • P501 Dispose of contents and container in accordance with local, regional, national and international regulations.

Substance as classified, dilutions may differ.

Questions

Is used freezing bath isopentane different from clean stock?

Yes. It may hold tissue fragments and ice, so it should be described as used rather than clean. Keep it in a labelled, closed container separate from unopened bottles and tell the collector how each is described on your list.

Is isopentane the same as methylbutane?

Yes, 2-methylbutane is another name for the same liquid. Make the label consistent across your stores so two names do not suggest two different products on your stock record.

Can we keep isopentane near the cryostat?

Keep only the amount needed for a run there, with no ignition source. Main stock stays in the ventilated flammables cabinet because it is extremely flammable and vapour travels. Return the working bottle after each session.

Guidance only. Check your own risk assessment and your supplier's safety data sheet.

Hazard data source: PubChem GHS Classification, retrieved 31 Oct 2026. Formula C5H12. EC number 201-142-8.

Request collection Add to register
Search the chemical database