Six people with nausea were put under quarantine after a suspicious package was discovered on the 25th floor of a downtown Vancouver office building Friday morning.

Vancouver Fire and Rescue Services described the package, which was found in the Bentall 5 tower on Burrard Street, as a damp envelope that’s believed to have caused a number of people to feel ill.

“The person that came into contact with it became sore throat, slightly nauseous, and that escalated to about four patients, it is now up to six,” said Battalion Chief Rod MacDonald.

A firefighter at the scene told CTV News the package, which was found in a mail room, “had a strange smell to it.”

One floor of the busy office tower was evacuated as a precaution after Hazmat teams were dispatched to the building around 11 a.m.

Police urged the public to avoid the area and office workers to “please stay calm” as the hazardous materials team removed the suspicious package.

Capt. Carol Messenger of the Vancouver Police Department said officers are still trying to determine what was in the envelope.

"Hazmat crews are investigating a suspicious envelope that has caused six people to exhibit some nausea symptoms," Messenger told CTV News Channel.

"They are being assessed by BC Ambulance. Our crews are still investigating what was in the contents of this envelope."

B.C. ambulance said an initial assessment did not reveal anything hazardous or unsafe.

First responders were on the scene for several hours, and the busy block was closed between Dunsmuir and Pender streets.

Messenger said the street closures were blocked off to give extra room for emergency responders to conduct their probe.

"That was more for our fire crew's safety -- not to alarm or cause any sort of panic about something in the air. That was really for our safety and we want people to remain calm and stay where they are for the moment," Messenger said.

The Bentall 5 building, or Five Bentall Centre, is a 35-storey skyscraper that houses offices for dozens of companies.

It was also used as the Grey Enterprises building in the Fifty Shades of Grey movie, filmed last year.