Patrick Martin Cayen, 54, was arrested Wednesday by Sarnia police and made a brief court appearance Thursday morning.
He is facing a total of 28 charges of sexual assault.
Police say there are two victims in the matter.
The investigation is ongoing.
Cayen has been the fire chief in Sarnia since October 2005.
A publication ban has been put in place regarding the time frame, location of offences and identity of the victims from being made public.
Cayen will make a court appearance on Dec. 18.
