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

Pentane (CAS 109-66-0): storage and disposal

Pentane is among the most volatile liquids on a teaching lab shelf, held neat as n-pentane or as a high purity grade in school, college and university stores. It is highly flammable, may be fatal if swallowed and enters the airways, can cause drowsiness and dizziness, and is toxic to aquatic life with long lasting effects. Its volatility makes bottle condition and room temperature the main practical concerns.

CAS number
109-66-0
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

Heat and oxidisers are the two things pentane must be kept apart from. Oxidising acids can ignite it, and a corrosive leak can break down the container and feed a fire. It goes in the ventilated flammables cabinet on a tray, well away from radiators, sunny windowsills and any equipment that gets warm. Because it is highly volatile, a bottle in a warm prep room can build vapour pressure. A bottle showing signs of pressure damage should not be opened or moved before specialist assessment. Only a spark-free refrigerator should ever hold it. Some stock arrives labelled as blowing agent or high purity grade, and the label should stay.

How to tell it has deteriorated

A technician is most likely to see an emptier bottle than expected, since pentane evaporates quickly through any imperfect seal. A cap that pops or hisses when loosened, or a bottle with a tight, bulging wall, means vapour pressure has built up and the bottle should be left alone. Pentane has no colour or crystal change to look for, so the container tells the story: a stained label, a dry cap liner and rings of residue at the neck. A bottle with a very low level may mean most of the stock has been lost to the air of the cabinet.

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.

Grouped with compatible flammable organics in a lab pack and packed by the collector in UN approved packaging, this liquid leaves the site only by specialist collection. Because of how readily it evaporates, a bottle that is bulging or hissing should be left where it is, upright and cool, and described to the collector in advance. It must never be poured away, burned off or left to evaporate in a fume cupboard. Packed stock in teaching labs fits 16 05 06*, and a loose discarded organic chemical not sent in a pack uses 16 05 08*. Say which grade the label gives.

Waste codes and transport details for Pentane
EWC code, laboratory chemicals16 05 06*
Discarded organic chemical, not a laboratory pack16 05 08*
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.

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

  • H225 Highly 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

Why does our pentane bottle hiss when we open it?

Pentane evaporates very readily, and vapour pressure can increase in a warm bottle. Do not open a bottle that is hissing, bulging or otherwise showing signs of pressure damage. Leave it undisturbed, keep ignition sources away and arrange a specialist assessment before it is handled.

Can pentane go in a normal fridge?

No. Only a spark-free refrigerator should hold a highly flammable liquid like this, because an ordinary fridge has internal sparking parts. If you do not have one, keep it in the ventilated flammables cabinet instead.

What do we do with an almost empty bottle?

Keep the cap on, keep it in the flammables cabinet and list it for collection like any other bottle. Empty-looking containers can still hold vapour and residue, so do not rinse or vent them yourself.

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 203-692-4.

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