Hazmat teams are closing in on what was to blame for the evacuation of a downtown building Monday afternoon.

Vancouver Fire's Lieutenant Carol Messenger says hazmat members believe the chemical, hydrogen fluoride is likely to blame.

"currently they have entered the building on two occasions to  try and determine the source of what was causing headaches - the people in the Shoppers Drug Mart that were feeling nauseous and ill."

Messenger says eight people in the store at the base of the building reported feeling off just before noon -- five were checked out in hospital.

Hazmat found the chemical on the third floor of the building - Messenger says they are working on securing the premises for re-entry.