Residents of a 21-storey condo building in downtown Vancouver hope to find out soon when their homes will be safe again.

Hundreds were evacuated from the building late Friday, but returned a few hours later when smoke from a renovation project was cleared and a specialist in building hygiene issued the all-clear.

A second evacuation was ordered Saturday -- and remains in effect -- after fumes built up again, leading to concern that unknown chemicals may have contaminated everything from carpets to clothing in the suites.

The first building hygienist was hired by the renovation company that caused the fumes, but the condo strata council has now hired its own specialist and says a new report is due Monday.

It's hoped the report will identify the chemicals in the fumes, allowing experts to estimate when residents can return.

The fumes were caused when the contractor replacing some tiles used chemical foam to raise concrete in the basement and noxious fumes filled the tower.