What Should You Not Store In A Shipping Container?

When space is tight, a shipping container is a brilliant way to keep equipment, stock, tools and personal belongings safe and secure.

However, it’s important to be aware that there are some things that you must not store inside a shipping container as well as a few others that you probably shouldn’t! Knowing the difference protects you, your stored items and everyone else on site.

At Upminster Containers, our goal is to make storage straightforward, which is why we’ve created this blog. Here is a list of items that can and cannot be stored, why those rules exist and what to do instead.

The ‘Do Not Store’ List

These restrictions aren’t box-ticking; they exist to protect people, property, the environment as well as to make sure that your insurance stays valid:

• Food or perishable goods (unless they’re securely packed)
• Living creatures of any kind (birds, fish, animals, insects)
• Liquids or combustible/flammable materials such as petrol, diesel, oil, paint, solvents, cleaning fluids or compressed gases of any kind
• Weapons, ammunition or explosives
• Chemicals, radioactive materials or biological agents
• Toxic waste, asbestos or any potentially dangerous material
• Anything that emits fumes or odours
• Illegal substances or unlawfully obtained goods (including counterfeit items, illicit tobacco or alcohol, unlicensed medicines, unsafe products and anything related to the storage or manufacturer of drugs)
  
  

Why These Items Are Prohibited

• Fire and explosion risk: Flammables and compressed gases can ignite or explode in an enclosed steel unit, especially on hot days.
• Health hazards: Toxic, corrosive or biological materials can harm users and contaminate neighbouring units and the wider site.
• Legal compliance: Weapons, illegal goods and unlicensed materials are strictly off-limits.
• Pest control and hygiene: Perishables and anything with an odour can attract pests and create sanitation issues. You can read more about preventing mice and other pests here.
• Insurance issues: Storing prohibited items will invalidate site rules and may also invalidate the cover that you’ve arranged for your goods.

Grey Areas Explained (And How To Handle Them)

A few categories deserve extra clarity:

Perishables
You may only store non-perishable food items if they’re properly sealed and packed; this is to make sure that they won’t leak, attract pests or produce odours. Open sacks of animal feed, loose grains or anything that can spill should not be stored.

Fuel & Oils
Even small amounts are classed as flammable liquids and are not permitted. If you’re storing machinery or a petrol lawnmower, drain the tank and then clean any residues before storage.

Strong Smelling Items
Fresh paint, strong chemicals, resins, recently treated timbers and waste materials can release fumes. If in doubt, don’t store them; the rule is no odours, no emissions.

Compressed Gases
Propane bottles, CO₂ cylinders, scuba bottles and aerosols fall under compressed gases and are not allowed in a storage unit.

Things You Probably Shouldn’t Store (Practical Advice)

Beyond the strict ‘do not store’ list, there are items that are technically allowed but rarely a good idea. If you’re unsure about any of the below, simply double-check with our team and we’ll let you know whether an item is suitable and if so, how best to pack it:

Cash, Jewellery And Irreplaceable Documents
High-value items, even when insured, are better stored in a safe. This includes original documents which should be duplicated and kept off-site.

Temperature-Sensitive Items
This includes certain musical instruments, fine art, wines and delicate electronics. Unless you’ve arranged appropriate lining/insulation and protective packing, these are best stored elsewhere.

Dirty Or Damp Goods
Moisture brought into a container raises the risk of condensation, which can damage everything else inside; always dry and clean items before storing.

How To Pack What Is Allowed (To Keep It Safe And Compliant)

A well-packed container stays safer, pest-free and is easier to access:

• Raise items off the floor: Use pallets or racking to improve airflow and reduce the chance of moisture seeping into boxes.
• Use breathable covers: Choose cotton sheets or moving blankets rather than plastic, which can trap condensation against surfaces.
• Seal boxes properly: Avoid half-open boxes that shed dust or smell. We also always recommend labelling each one.
• Distribute weight evenly: Don’t overload one end of the container and keep heavy items stored in low positions.
• Leave a gap to the roof and doors: This is so that the air can circulate and doors open easily.
• Ventilate on mild, dry days: A short airing helps to reduce humidity inside.
• Check door seals: Check these regularly and report any damage so that we can help before it becomes a problem.

What If I Need To Store Something On The Prohibited List?

If you tell us what you need to store, we’ll suggest a compliant alternative. Sometimes that’s a different product, sometimes it’s a simple change to how/where you store it:

• Flammable liquids and fuels: Use a regulated hazardous-materials store or a certified fuel cabinet located in a suitable, ventilated area; not inside a standard container.
• Gas cylinders: Follow your gas supplier’s approved storage and handling guidance; never in a closed steel unit.
• Chemicals or hazardous waste: Follow manufacturer and legal disposal advice as specialist storage/disposal will be required.
• Perishables: Consider dedicated refrigerated storage or keep only fully-sealed, pest-proof containers for short periods off-site.
• Firearms/ammunition: To adhere with legal regulations, storage of these items requires approved security protocols which a standard shipping container is not set-up for.

A Quick Reminder About Site Rules And Responsibilities

For everyone’s safety and comfort our depot licence also requires that you adhere to the below. These aren’t just formalities; they make sure that we can keep the site running safely for all of our customers:

• Don’t use the unit as living accommodation, an office or a business address, unless you are hiring an office from us
• Don’t connect utilities (power, water, drainage) unless specifically authorised in writing or already connected
• Don’t carry out mechanical work or spray painting in or around the unit
• Keep passageways clear and dispose of waste properly
• Inspect your unit regularly and notify us of any damage
• Arrange your own insurance for the full replacement value of the goods that you store and keep that cover in place for as long as they’re in storage

A Quick Checklist

If you’re preparing your first load, we recommend running through this simple checklist. If your item comes under any of these then it’s not suitable to store in a shipping container at our depot.

 Anything that is:

• Flammable, explosive or pressurised
• Toxic, corrosive, reactive or otherwise hazardous
• Illegal, counterfeit or unlicensed
• Alive (plants, animals, insects, fish, birds)
• Smelly or likely to leak
• Perishable (unless securely sealed and pest-proof)

How Upminster Containers Can Help

A container is a tough, versatile space but it isn’t the right home for everything. Sticking to the ‘do not store’ list will protect your goods and keep you compliant with site rules and the law as well as ensuring a safer environment for everyone around you.

Our services:

• Buy or hire: Choose from a wide range of new and used containers in a range of sizes
• Conversions: Add shelving, lining/insulation, vents and electrics (where permitted) for cleaner, drier storage
• Self-storage: Flexible depot storage with advice from a friendly team
• Modular buildings: When you need a purpose-built, compliant space rather than a storage unit.

The Upminster Containers team are here to make storage simple. If you’re unsure about a specific item or would like advice on lining, shelving or ventilation, simply call 01708 225350 or get in touch with our team via the contact form below. We’ll help you to store the right things, the right way.