As well as boiler/cylinder lagging, there is graphited asbestos used in stuffing glands and also for mudhole/manhole door joints, It was also widely used in sheet material used for making steam-tight joints and it not unreasonable to expect that some of this may still be encountered. Whilst it is now illegal to sell asbestos-based products for the above purposes, I do not believe it is illegal to use it (for example if you have the materials in stock).