Aga Cookers and Asbestos
We've been restoring Aga Cookers for decades and frequenty come across the question "Does My Aga Cooker Contain Asbestos?".
The internal cavities of Aga Cookers have historically been filled with loose-fill insulation. Inside the cooker body, there are lots of pockets and gaps around the cast iron conductions and burner casings etc. The insulation was poured inside after the build was complete, to rid the cooker of air pockets and insulate the cooker body.
Diatomaceous Powder Insulation
Early models of Aga cooker, like the Standard models made from the 1950's through to the Deluxe 1974 models (and some post-1974 models), would have originally contained Kieselguhr insulation power (or 'Diatomaceous Earth'). You can identify your model here.
This is a fine, talc-like insulation, made from crushed up fossils called diatoms. It's satisfying to touch, but VERY messy to work with and instantly becomes thick clay once exposed to water or moisture. The good news is that amorphous diatomaceous earth is non-toxic. As with anything in powder or dust form - minimising exposure is key. You don't want to be breathing in lung-fulls of any dust or powder. If you're working with it, the proper PPE should be used; not just cloth or paper dust masks.
Whilst the loose fill insulation may be ok, these models are still the most at risk for any asbestos exposure. AGA used asbestos rope seals inside their cookers for many years. These seals and gaskets are found inside the body of the older models explained above, and also around the lids and doors. Over the lifetime of these cookers, many of these gaskets and rope seals have been replaced for modern (safe) equivalents.
AGA have previously reassured engineers and customers that undisturbed, these seals pose little risk and were of 'dust suppressed' or 'tightly woven' formats. Many of them have been exposed to moisture or grease over time which hardens them, meaning they're less friable in nature. They recommend that really old models of cooker are removed in one piece if possible and disposed of professionally.
Vermiculite Insulation
"Newer" Aga Cookers from 1974 onwards would have contained Vermiculite. This is now commonplace for any refurbished oil, gas, or 13amp Aga cookers. Vermiculite is a naturally occurring mineral which is mined, thinly sliced, then heated until it 'pops' like popcorn, to produce chips of insulation. There is no asbestos inside vermiculite - they're two different minerals.
There is some talk online about the vermiculite mine in Libby, Montana. This vermiculite was popularly sold as 'Zonolite' for home attic insulation, and primarily used across the united states. In the 1960's, asbestos contamination was found in the mined vermiculite. At this time, AGAs were mainly using the Kieselguhr powder mentioned above, then switched to vermiculite likely sometime after 1980's.
Most of the vermiculite used in the UK comes from China and South Africa, and we have strict testing and regulations. Although the chance is never nil, it's less likely that your Aga Cooker contains asbestos inside the loose-fill insulation.
Whenever you're working with an older model of Aga Cooker, please take precautions and wear correct PPE for the job. If you're looking to purchase an older refurbished model, find an established, trusted, professional company. You never know if your engineers are re-using older insulation, cutting corners to save on cost, or just ill-informed about the risks and material they're working with.
Some Further Reading:
