SOLVED. YA mystery where school kids spontaneously combust? [s]

[Cassie]

I only read a sample of this book online before losing it, but it was about a teenage girl in a school where the pupils start to spontaneously combust at any time and no one knows why. It's pretty recent so probably published in the last three years or so, and I'm pretty sure it had a female author though not absolutely certain. It was kind of a dark mystery/psychological thriller genre, very strange but really good so any help is welcome. Thanks.

[Krista]

Might be Spontaneous; it's not out yet, but there may have been a sample chapter somewhere!

https://www.goodreads.com/book/show/2...

[Cassie]

This is it, thank you!