An 18-year-old boy was in Victoria General Hospital with severe head injuries on Wednesday after an accident involving fireworks on Halloween night.

Police believe the teen and some friends were setting off homemade fireworks in suburban Saanich.

Staff Sgt. Terry Parker said officers found the badly injured youth in Marigold Park just after 7 p.m. on Tuesday.

"They located an 18-year-old male who was unconscious and appeared to have suffered head injuries as the result of an explosive device which was made out of, possibly, fireworks."

The youth underwent emergency surgery.

Parker said investigators were interviewing the victim's friends.