Many thanks to TOR for an advance copy of City of Broken Magic by Mirah Bolender, about a magical bomb squad. It sounds fantastic and comes out in November.
Five hundred years ago, magi created a weapon they couldn't control. An infestation that ate magic-and anything else it came into contact with. Enemies and allies were equally filling.
Only an elite team of non-magical humans, known as sweepers, can defuse and dispose of infestations before they spread. Most die before they finish training.
Laura, a new team member, has stayed alive longer than most. Now, she's the last-and only-sweeper standing between the city and a massive infestation.