a friend asked what happened to the devices when people are cremated.
Interesting question so though I would ask.
The other thing is icd/pacemakers have lithium batteries,, much like the mobile phone, ev vehicle and power station battery storage but smaller. Lithium batteries are known to have thermal runaway. Not something that your local crematorium would bear thinking about. (Sarcasm, but element of truth)
They are removed by the undertaker and can be donated to animal charities for use in dogs.
In a previous life I was involved in the management of a crematorium. Environmental regulations mean they have to be careful over emissions - so stuff that could pollute and can be removed will be. That can mean artificial joints, pacemakers, ICDs and so on. To remove pacemakers undertakers should usually have been on appropriate training courses. It's always worth making sure your chosen undertaker knows their stuff.
Non removable prosthetics, fillings and so on are the reason why crematoria have elaborate filters on their chimneys - crems can be significant contributors to levels of environmental mercury..
Newer devices are fitted with lithium iodine batteries. We all know what lithium is like . At the temperature that cremation are it’s a fire hazard. The client may be dead, but is potenually an incendiary bomb
Yep, the bill for repairs would be spectacular.... It gives undertakers incentives to get it right...
My parents undertaker asked on each occasion if they had pacemakers . . .
Swimming and Yoga with an ICD
Walking Munro's with an ICD
Smart watch with an ICD
What is life like with an icd? 
Travel anxiety with an ICD
