Fire fighters are 94% volunteers. So not sure why they'd do that...
See here:
"It is important to know that most of the fire stations/departments do not pay for the services of a volunteer firefighter. However, they may get reimbursed for attending training and meetings, responding to fires and emergencies, and time spent on shifts. The amount of reimbursement is generally at the discretion of the fire department."
https://www.firesciencedegreeschools.com/how-to-become-a-vol....