Storing lab chemicals safely: flammable and COSHH cabinets and spill kits

Safe chemical storage means keeping each chemical in a cabinet suited to its hazard, away from anything it could react with, with a spill kit close by. Most lab accidents involving chemicals don't happen during an experiment. They happen on a shelf, in a fridge or on the floor: a bottle knocked over, two incompatible chemicals stored side by side, a solvent vapour reaching a spark. Good storage and a few pieces of safety equipment prevent most of them. This guide covers the UK rules behind chemical storage, the main types of storage cabinet, how to keep incompatible chemicals apart, and spill kits.

It gives general information. It isn't a substitute for your organisation's own risk assessment or the safety data sheet for each chemical. Terms are defined in the glossary.

The rules behind chemical storage

Two sets of UK regulations cover most chemical storage in a lab:

Both start from a risk assessment. The safety data sheet for each chemical gives the starting information: section 7 covers handling and storage, section 8 exposure controls and protective equipment, and section 10 which substances it must be kept away from.

Flammable cabinets

Flammable liquids, such as acetonitrile, methanol, ethanol and acetone, give off vapour that can catch fire. A flammable cabinet doesn't stop that. Its job is to keep the liquids out of a fire for long enough for people to get out safely.

HSE's guidance on storing flammable liquids in containers, HSG51, sets out what a cabinet or bin in a workroom should provide (HSE, HSG51):

• Fire resistance: at least 30 minutes' fire integrity, with no gaps at the joints and doors that close tightly against the frame.
• Spill containment: a sump that can hold 110% of the largest container normally stored in it.
• Recommended maximum quantities: no more than 50 litres of extremely and highly flammable liquids, or of flammable liquids with a flashpoint below the room's maximum temperature. For other flammable liquids with a flashpoint up to 60 °C, the limit is 250 litres.
• Location: in a well-ventilated area, away from the immediate work area where possible, and never blocking an escape route.

Under DSEAR, the inside of a cabinet holding low-flashpoint liquids is normally treated as a zone where a flammable atmosphere may occur, so nothing inside should be able to spark. Cabinets built to the European standard BS EN 14470-1 are furnace-tested and classed by how many minutes they resist fire, up to 90 minutes. They go beyond the legal minimum and can help where larger quantities are kept.

Keep only what is needed for current work in the lab. Bulk stock and empty containers that still hold vapour belong in a dedicated store.

Flammables in a fridge

Never store flammable solvents in an ordinary domestic fridge. The thermostat and light switch can spark inside the cabinet, where vapour collects. Use a fridge or freezer designed and labelled for flammable materials. For storing samples cold, see freezer temperatures for sample storage and fridge temperatures for storing samples.

COSHH cabinets and corrosive cabinets

COSHH cabinets hold substances that are hazardous to health but not flammable: toxic, harmful and irritant materials. They are usually steel, lockable, labelled with the hazard pictograms of their contents, and fitted with a sump tray. Locking limits access to people trained to handle the contents.

Corrosive cabinets hold acids and alkalis. Corrosive vapours eat into bare steel, so these cabinets are made of or lined with resistant material, often plastic, and may be ventilated. Acids and alkalis should be on separate shelves or in separate cabinets, each with its own tray.

Keeping incompatible chemicals apart

Some chemicals react dangerously if they mix after a spill or a broken bottle. Store them apart, not just on different shelves of the same cabinet.

The safety data sheet's section 10 lists the incompatibilities for each chemical. Store by hazard class, not alphabetically: an alphabetical shelf can put an acid next to a cyanide.

Spill kits

A spill kit holds absorbent material and tools for containing and cleaning up a spill. Kits come in three broad types, usually colour-coded by makers:

Yellow for chemical kits and white for oil-only kits are the common UK convention (Xamax), but colours vary between makers, so check the label rather than the colour.

Choose a kit large enough for the biggest container that could spill, and keep it close to where chemicals are stored and used. A kit typically contains absorbent pads, socks to stop a spill spreading, gloves, eye protection and bags for the waste. Some chemical kits also include neutralising agents for acids or alkalis.

Used absorbent takes on the hazards of what it soaked up, so dispose of it as chemical waste, following section 13 of the safety data sheet and local procedures. Restock the kit straight after use.

Eye protection

Wherever chemicals are stored or handled, suitable eye protection and an eyewash station or sealed eyewash bottles should be within easy reach. For the difference between safety glasses, goggles and face shields, and the standards they are tested to, see safety glasses, goggles and face shields.

A storage checklist

• Every container is labelled with its contents and hazards.
• Each chemical has a safety data sheet to hand, and storage follows its section 7.
• Flammables are in a fire-resisting cabinet, within the recommended quantities.
• Incompatible chemicals are kept apart.
• Toxic substances are locked away, with access limited.
• Corrosives sit in trays, acids apart from alkalis.
• A suitable spill kit and eyewash are close by.
• Moisture-sensitive solids are kept tightly closed, with a desiccant where the safety data sheet calls for dry storage.
• Stock is checked regularly, and old or unneeded chemicals are disposed of properly.

Related guides

For COSHH assessments, safety data sheets and hazard pictograms, see COSHH and safety data sheets. For ventilated enclosures, see fume cupboards, laminar flow hoods and biosafety cabinets. For the solvents often kept in flammable cabinets, see HPLC and LC-MS solvents. Each product page has a safety data sheet link in its resources, or says the sheet is available on request. For the particular hazards of cryogenic liquids, see liquid nitrogen and cryogenic storage.