Syd pool business fire prompts evacuations

A fire at a pool chemical business in northern Sydney has forced the evacuation of more than 60 people from neighbouring homes.

Smoke spread across Hornsby and Asquith because of the blaze which has severely damaged the Jersey Street, Hornsby business which went up in flames just before 6am on Sunday.

Four people have been treated by paramedics because of the smoke, while others have been told to keep their doors and windows closed.

The cause of the fire has not yet been determined.