A number of people had to be decontaminated at Georgian Bay General Hospital after being sprayed with a noxious substance.
Southern Georgian Bay OPP were called around 8 p.m. on Sunday about a disturbance at a Frederick Street home in Midland.
They found a number of people had been sprayed with a noxious substance that was similar to bear spray.
Police searched an upper floor apartment and arrested a 20-year-old Midland man.
He is up on a number of charges including four counts of assault with a weapon and four counts of administering a noxious substance.