My sheets caught on fire at the laundromat yesterday morning

I use avocado oil as my massage medium.

I've been dropping my linen laundry off with this laundromat for the past 4 years now, about twice a week. The owner called and said the sheets were washed and dried, but the girl working that night just left them in the dryer overnight after they were finished. He watched the cameras back and after sitting in the dryer for about 11 hours, 15 minutes before his opener showed up the dryer started smoking and caught fire.

The owner was super cool about it and is reimbursing me for my order, but asked that I send him a list of the products that I use so the fire marshall and his soap distrubutor can take a look and try to figure out what happened.

I know oil soaked towels & rags can spontaneously combust under high heat, but after being washed AND dried? And hours later?? And it's not like I'm dousing my clients in oil when I massage them, so the sheets aren't "soaked".

Is this a thing that has happened to anyone else? Did we learn anything about this in school? Because if so, I definitely don't remember!