Hazard symbols on canister glues – do you know the dangers?
One canister glue looks much the same as another. It’s easy to assume that price and performance are the only material differences to consider. But understanding the hazard symbols on these canisters can tell a very different story – and many aren’t aware that it can be the difference between life and death.
Understanding the common symbols
Most people will recognise the ‘Flammable’ hazard label and know that almost all canister or aerosol products with propellants are highly flammable. The ‘Hazardous to the Environment’ label is fairly self-explanatory. And many will also recognise the ‘Health Hazard’ label, which indicates risks related to contact with skin, eyes, and inhalation.
All these symbols are significant and carry important messages for users. But there’s one more.
The hidden risk:
Serious Health Hazard symbol
It’s the final symbol that many don’t understand – the ‘Serious Health Hazard’ label. Yet it’s arguably the most critical to recognise.
Use of spray adhesives displaying this symbol requires real caution. Of course, it’s far better to choose products that don’t carry this symbol, because risks to health are better avoided than controlled, wherever possible.
What the Serious Health Hazard symbol really means
When it comes to canister glues, the presence of this symbol almost always indicates one thing: the presence of Dichloromethane (DCM).
DCM is a conventional propellant used in aerosol products, coming into widespread use in the 1970s and 80s. By the 1990s, its health risks were becoming recognised, including potentially causing cancer, and in 1999 it was classified as a ‘suspected human carcinogen’ based on international evaluations of its effects on rodents.
Due to the understandable absence of testing on humans and a lack of irrefutable evidence, it remains only a suspected carcinogen – Hazard Code H351 – and is therefore still included in products with just the ‘Serious Health Hazard’ symbol to warn of its presence.
But the cancer risk is only part of the picture when it comes to the hazards of DCM.
Beyond cancer: the risk of asphyxiation
All gas propellants work on the same principle: they are filled at the top of the can or canister, which is pressurised, above the substance (e.g. glue) itself, and a tube runs from the release nozzle down to the bottom of the can. When the release valve is activated, the pressurised gas pushes down towards the bottom of the canister in order to escape through the tube. In doing so, it pushes the substance out with it.
However, not all propellant gases are made equal.
DCM is 2.93 times heavier than air, which means it settles at floor level indoors and gradually fills the area the more it’s used. When inhaled, it metabolises within the body into carbon monoxide, which binds to haemoglobin and reduces oxygen transport.
This makes the risk of asphyxiation much higher than with other propellants – especially in low-level applications like flooring.
Combine this with the cancer risk, and the dangers are far greater than that subtle, often misunderstood hazard symbol suggests.
Safe DCM use requires serious precautions
Very good ventilation, clearly prescribed working practices, and comprehensive PPE are therefore essential when using DCM-based glues.
This is particularly critical given that DCM is virtually odourless, so a build-up of high concentration levels can go unnoticed unless proper monitoring systems are in place.
A safer alternative:
Timbond Professional NC spray adhesive
In light of all this, we strongly recommend a universal shift away from canister glues containing DCM.
While we still supply our traditional Timbond Professional Spray Adhesive where customers specifically request it for economy purposes, we highly recommend the NC (non-chlorinated) alternative.
The Timbond Professional NC Spray Contact Adhesive uses the solvent Methylal, which is lighter than dichloromethane, having a different chemical structure and properties. Methylal does not produce carbon monoxide in the body, and its main advantage is that is not classified as ‘H351 suspected of causing cancer’. While ventilation is still required during use, it is a significantly safer alternative to dichloromethane, especially as it carries a distinctive odour that makes any accumulation immediately apparent.
Switching to the non-chlorinated Timbond Professional Spray Adhesive is entirely straightforward, with no changes required to production processes.
The cost is slightly higher, but relatively insignificant in the context of overall production – and a price well worth paying for dependable user safety.
Final thoughts: responsibility matters
It is essential that hazard symbols on canister glues are understood by those in positions of responsibility, to ensure that duty of care is fulfilled. Failing in this responsibility could have serious implications for both staff and the business.
The safest option is to avoid use of spray adhesives with the ‘Serious Health Hazard’ warning symbol. But if you do choose to, always ensure that training and safe-practice measures are in place.
