Several people who work at a building housing Interim Liberal leader Bob Rae and MPP Glen Murray’s office were treated Tuesday after an envelope containing white powder was delivered, causing a scare, police say.

The envelope was dropped off at the building, at 514 Parliament St. near Gerrard St. E., around 2 p.m. Seven people became sick and started coughing and sneezing. Those affected were treated at the scene and no one was taken to hospital.

Rae and Murray share an office. Two of Rae’s staff and five of Murray’s were affected by the powder, according to a spokesperson for Murray.

The woman who delivered the envelope, who was around 50, was arrested. Her name is not being released, and police are still looking into her motivation for dropping off the envelope. They said they believe she may have mental health issues.

The contents of the envelope are still being analyzed, but police do not believe the incident was an anthrax scare.

Murray released a statement on his website later in the day saying he is proud of his staff for the way they handled the situation and for their “courage and grace.”

“Public service entails risk, which is borne not only by elected officials, but also by our staff.”

Police said calls for suspicious packages are not common.

“This is not a consistent problem, but there are occasional calls,” said police spokesperson Const. Tony Vella.

Police had the immediate area blocked off between Wellesley St. E. and Carleton St.

It is still unknown whether charges will be laid.