Recycled shipping containers are prone to carrying hazardous substances due to the fact that they were built to withstand extreme weather conditions while protecting goods. This meant that the wooden floors and paints used were heavily treated with toxic chemicals. Note that even the container itself may have been used to transport toxic substances. However, all this can be mitigated by proper cleaning and treatment to turn into a healthy home by replacing or covering the floors, and sandblasting or covering the paint. Opting for newer containers also prevents any toxic chemicals from being used on your container, however, you rid of the sustainability factor in reusing a shipping container.
Why and What are the Toxic Components of Shipping Containers?
Being first and foremost designed to transport goods for months at sea, containers were built for extreme weather to protect non-living things. This means their priority was using any chemicals necessary if it means they will last longer without corroding, being damaged at sea or in fires, and pests coming in.
Therefore, the paint and wood they would use for containers aren’t the best for humans and may actually put your health at risk.
It is highly probable that shipping containers carry toxins, whether that’s in their finishes or what they used to hold inside.
The container’s wooden floors may have been treated with strong chemicals to ensure it doesn’t attract pests or corrode from any water or fire damage. The paints used often contain chromate and phosphorus as protection from saltwater, but can be hazardous to our health. Not to mention if the container was used to transport toxic items, there may be some spillage contaminating the container for years after. (1)
However! There are ways to eliminate the health risks of containers. For starters, carefully choose your container in making sure they did not carry any toxic substances. Newer containers (now that they know people turn them into homes after their use) are not coated with toxic paint and are a safer choice.
Older containers, though cheaper and more sustainable in recycling are riskier in health. You can however still mitigate its hazardous past by completely replacing the wooden floors with marine plywood. Marine-grade plywood typically comes from pine or Douglas fir, and is naturally water-resistant compared to other plywood, not needing chemicals. Note that removing the floor will need safety gear and entail some debris. You’ll need to take care to not accidentally inhale any of the toxic fumes as you remove the old floors. This may require additional equipment such as masks and ventilation fans. (2)
A cheaper alternative would be using a non-breathable flooring layer on top to protect you from any toxins present on the wooden floor. Afterward, your chosen tiles or paneling can then be placed above the underlayment, serving as your main floor. (1)
Removing the old flooring involves a lot of work and the risk of distributing harmful fumes into the air. Instead of removing the wood, you can cover it with new flooring. (2)
This strategy of a non-breathable flooring underlayment was used by Larry Wade of Sea Container Cabin in 2010. He used this method on his own container home. (3)
“The marine paint used on shipping containers contains high levels of lead, chromates, and other toxic metals. Studies show that exposure to certain types of lead paint can cause sleep disorders, depression, and damage to the lungs and nervous system.” (2)
This paint can be sandblasted off or encapsulated, both of which we’ll discuss in a bit. However, do note that even in cutting your container for doors and windows, welding and sandblasting can also expose you to the hazardous chemicals of the paint. Therefore, extra care must be taken when doing construction work on the container. (2)
The paint on the other hand can be sandblasted off and re-painted or cladded. Take note that sandblasting requires more equipment, safety gear and manpower to achieve.
As previously mentioned, sandblasting still exposes you to the previous toxic layer in the form of toxic dust. Be careful in handling this, disposing it properly and completely, avoiding that none of it catches in the breeze, becoming a dangerous fume to inhale. Sandblasting can consist of abrasive material or thermal methods (or heat application). Be careful with the thermal method as it may lessen the strength of your container. (2)
One can also encapsulate or “paint on top” with a non-toxic paint or spray foam insulation to protect those inside from any toxic fumes and physical contact. (1)
Call your manufacturer to determine if the paint used on the container contains toxic chemicals. If harmful substances were used, a good strategy would be spraying foam insulation on the inner walls. This protects you from any fumes as well as makes indoor temperatures more comfortable. (4)
“Doing so will create a complete vapor barrier which will prevent any residual fumes from harmful chemicals spreading inside your new shipping container home.” (4)
Encapsulation entails covering any toxic surface such as lead-based paint and asbestos with a new, non-toxic coating. One can choose among the following as “encapsulants”: (2)
- Polymers (preferred for their flexibility)
- Epoxies (preferred for their flexibility)
- Cement (often used on flooring)
Encapsulation is viewed as a cheaper and quicker option, while not posing the risk of being exposed to the toxic layer through sanding. This method keeps you from not touching the hazardous layer underneath. It’s best to clarify with your manufacturer which encapsulants you plan to use, to ensure they’ll bond well to the existing container wall finish. (3)
Further Steps You Can Take As a Homeowner
If you’re purchasing a brand new container, this is much easier to keep “healthy”, as you can simply specify to the manufacturer what you want it coated with and treated to house people instead of harmful substances to protect goods.
However, this drastically reduces your eco-sustainability points in opting for recycled shipping containers in the first place.
Buying used shipping containers does raise the health risk of the topics listed above. A good first step would be calling the manufacturer of the container, you may find them through the unique identification number on your container. Next, ask for a list of materials they used to build the container. Clarify if any of the coatings and paints used contained any toxic substances, specifically if any pesticides were used on the floors, or if any of the paints contained cadmium, chromium, or lead. This can be checked in the Material Safety Data Sheet (MSDS). (2,4)
Be mindful that in the process of renovating your container, there is still an opportunity for toxic chemicals to come in but these can be avoided with the careful selection of materials and treatment. (2)
Your wooden frames for your openings, framing, and plywood wall panels will be treated to prevent moisture damage and pest attraction. Try requesting for products that have little to no VOC (or volatile organic compounds) to make for a healthier home.
The best way to a healthy home is to make sure your materials, coatings, and treatments are non-toxic and pesticide free. Take the time to get to know what you’re buying and building into your space. You can also demand this information from your material suppliers and manufacturers. It can also help you determine which supplier you end up choosing!
- Are Shipping Container Homes Safe? | Sigma Container Corporation
- Are Shipping Container Homes Toxic? | 3 Best Ways to Avoid Exposure to Toxic Materials
- Are Shipping Container Homes Dangerous To Live In?
- Are there any Health Hazards to live in shipping container home?