What Not to Store in Shipping Containers: Expert Advice for Safe Storage

Shipping containers have become a key method of storage for many people, from businesses storing additional stock to individuals housing lesser-used items and valuables. However, while shipping containers are highly adaptable and can be used to store various items, there are restrictions on what you can safely store inside them. 

What items can you store safely in shipping containers?

While there is a long list of items you should not store in a shipping container, there are plenty that you can store safely and securely. The sheer size of shipping containers means you can store a variety of different items from a wide range of categories. You’ve just got to make sure they’ll all fit inside your shipping container without issues.  

As a guide, items that are non-perishable, non-hazardous, and legal can typically be stored in a shipping container. But before you store, it’s always best to ask for clarification if you’re unsure about an item’s suitability for storage. 

The most common items suitable for container storage include:

• Seasonal décor and equipment
• Furniture and home goods
• Business inventory and supplies
• Tools and construction equipment
• Sporting gear and bikes
• Vehicles

What you shouldn’t store in a shipping container

Before you start to load your shipping container, either for storage or transit, it’s important that you understand the items you can’t store in a shipping container.

Hazardous materials

Standard shipping containers cannot be used to store hazardous materials, period. Hazardous materials can pose significant risks to people and property, particularly in confined container spaces. They are also subject to strict regulations for both storage and transit. Risks include corrosion, damage, and health risks if not properly managed. 

The types of hazardous materials you should be aware of when it comes to avoiding certain items include:

• Hazardous chemicals like pesticides, poisons, strong acids, or industrial chemicals
• Asbestos products
• Biological waste, such as medical waste and biohazardous materials
• Explosives and flammable materials
• Propane, oil, gasoline, and paint

Radioactive materials are also included in this list. They are hazardous and difficult to notice immediately, which can be problematic if you’ve already been exposed to them unknowingly. Most storage facilities do not have adequate protection against radioactive effects for their personnel, which is why storage of these materials is often ruled out. 

The exception to hazardous materials is when specially designed dangerous good containers, like COSHH chemical stores, are used. These containers have additional safety measures and guidelines, making them secure to store certain hazardous materials. If you must store or transport hazardous materials, use only containers that are specifically designed and certified for hazardous material storage.

Sensitive electronics

Electronic items and devices are vulnerable to temperature, humidity, and dust. Standard shipping containers cannot protect them from damage as they are unable to maintain a stable temperature inside. In hot climates, shipping containers effectively become ovens, while in cold climates, they will feel much colder inside. 

Extreme temperature swings can significantly damage electronics and devices, reducing their lifespan or completely damaging them. Alongside temperature fluctuations, condensation may also form in containers, resulting in moisture build-up, which is also problematic for electronics. Moisture can lead to corrosion, short circuits, and other issues that can damage your items for good. 

If you’re transporting electronic items, movement and vibrations can also physically harm your devices. To ensure the safety of your electronics, climate-controlled containers are a great choice. They will regulate temperatures and minimise the risk of condensation.

Likewise, you should protect your items with adequate, waterproof padding and consider moisture-absorbing packets or damp sticks. 

Valuable or irreplaceable items

Shipping containers can be susceptible to weather damage and theft, both in transit and when used on land. Storing valuables inside a shipping container is generally not recommended unless additional security and protective measures are in place. Strong locks, surveillance, secure placement, and adequate weather protection can help protect your valuables. 

Heat-sensitive items

Many items are heat-sensitive, and since shipping containers can become extremely hot in warm climates, direct sunlight, or during transit, this can pose a risk. Sensitive items such as electronics, documents, and perishables should not be stored in a standard shipping container due to the risk of warping, malfunctions, or spoilage if the container becomes too hot. 

If precautions are taken and modifications carried out, sensitive document storage is a possibility in shipping containers. You will need to ensure humidity is well controlled to prevent mould and mildew build-up. Proper packing and making sure your container is watertight are also essential for protecting your items and preventing losses. 

Items prone to melting or warping

Depending on their material, some items may be more susceptible to melting or warping in warm temperatures. For example, vinyl records, art supplies, candles, and plastics are all heat-sensitive and could become damaged if not properly protected. 

Any items that are prone to heat sensitivity should be stored in temperature-controlled storage. If you choose a shipping container to store these items, you need to make sure vents, insulation, and reflective coatings are used to regulate the container temperature in hot climates. 

Flammable items

Flammable materials should not be stored in standard shipping containers. The confined nature of shipping containers means they can quickly become firetraps. Gasoline, propane, paint thinner, and fireworks cannot be stored in a shipping container due to their significant risk as a fire hazard.

Some items may not be directly flammable, but could still pose a risk, for example, garden equipment like petrol lawn mowers. These can be stored, but gas or oil should be drained before storage. If you are storing items such as this, with the potential for a fire risk, you need to follow careful hazard consideration and safety measures. 

Flammable materials should only be stored in fire-resistant containers and away from heat sources. Your unit should be tightly sealed to prevent leaks and vapour release, while also having proper ventilation added to avoid flammable vapour buildup. Most products and items will come with safety guidelines regarding flammable materials – you should read these thoroughly and make appropriate alterations to your container before you store them.

Explosives

Shipping containers are unsuitable for storing explosives. If detonated, explosives are extremely reactive and can cause significant damage, particularly within a shipping container due to its enclosed nature. Small changes in temperature or pressure can instigate a reaction, with even minor shocks having the potential to cause a wider explosion. 

While explosives in a container alone are dangerous, the risk is further increased if you are inside at the time of an explosion. Shipping containers have a lack of escape routes in their standard form, making it difficult to escape should an explosion happen. 

Weapons

Storing weapons inside a shipping container is not recommended. Uncontrolled humidity inside a container can cause weapons such as firearms to rust and corrode, making them even more dangerous than they were before. Illegal or improper weapon storage can also result in legal penalties, including fines or imprisonment.

Liquids

Another category of things you should avoid storing in your shipping container storage unit is liquids, primarily due to the possibility of leakage. Unexpected leaks can be problematic due to the risk of losing the item you were storing, as well as causing damage to other belongings affected by the leakage. 

Although it might seem safe to store cases of water in a shipping container, this should not be done over a long period of time. Stockpiling items like bottled water for an extended period can cause plastic bottles to release bisphenol A (BPA) into the water, making it undrinkable and unsafe. 

Things you can store in modified containers

There are also a couple of categories of items that at first glance should not be stored in a shipping container. However, due to the versatility of shipping containers, adaptations can be made to make storing these items a possibility. 

Food items and perishable goods

Food and perishables should only be stored in shipping containers that have been modified with adequate temperature control and ventilation. In standard shipping containers, temperatures frequently fluctuate, causing decay and attracting pests. Without proper care and attention, shipping containers can quickly become a breeding ground for bacteria, particularly if you’re storing fruit, vegetables, meat, or dairy products. 

Climate-controlled shipping containers are necessary for storing or transporting food and perishable items. Frozen goods cannot generally be stored in climate-controlled units and will need suitable refrigeration. In this case you should consider a specialised storage solution such as a refrigerated shipping container. 

Animals or plants

Plants and animals should not be kept in standard shipping containers unless they have been extensively modified, and the storage is temporary. Without conversion, shipping containers do not have adequate ventilation, light, and temperature control for living things to survive. 

Animals and plants have complex needs that are not met by shipping containers, and it is incredibly unsafe to store them in a unit unless you have modified them to suit. Even then, it’s only recommended that you store plants and animals in a shipping container temporarily, for example, while moving livestock paddocks. 

You could, however, use shipping containers to support the care of animals and plants. As an example, you could create a mushroom farm or tack room for horses with a modified shipping container.

While it is possible to use shipping containers for animals and plants on land, it’s ill-advised to use them for transportation. You should always use alternative, regulated methods to transport living organisms, such as livestock vehicles or specialist plant and agricultural transportation. 

The bottom line

While shipping containers are a versatile and secure storage option, unfortunately, they’re not suitable for everything you might like to store. Without specialist shipping containers, you should always avoid storing hazardous, flammable, perishable, and heat-sensitive items. However, these items are relatively niche and not commonly stored, leaving you with a huge selection of items that can be stored safely in a shipping container. 

If you’re keen to explore how a shipping container can be used to store your items, or you’re in the market for one already, contact our team to find a suitable unit for your needs.

FAQs

Do items get damp in shipping containers?

Shipping containers can experience dampness from humidity and temperature fluctuations, causing what is known in the industry as “cargo sweat”. This issue is further exacerbated by storing or transporting items with a high moisture content, as this moisture can be released and cause dampness to other items in the unit. 

Whether you’re storing or shipping, maintaining dry conditions and installing proper ventilation are critical for promoting air circulation and minimising moisture build-up in your container.