Some interesting comments from the 7 Oct. 2001 Toronto Sun article, "Disaster waiting to happen," p.30 & 32 (author ??) :
...said Ross, lead witness in Canada's first Special Committee on Terrorism and Public Safety in 1986. "I immediately thought of the CN Tower... that would be a spectacular target that would get a lot of attention. Not far away, you've got the SkyDome and large concentrations of business...
Pat Quinn, of Quinn Dressel and Associates, who designed the Scotiabank and Royal Bank towers and the World Trade residences at Harbourfront, said......the chances of the ScotiaBank building buckling after an aircraft collision are "very small" because it is a "much tougher building" than the Trade Center.
While he agrees the CN Tower would be a spectacular target for another hijacked aircraft, Quinn said a plane hitting the reinforced concrete shaft "would be like throwing a piece of butter against a brick wall."
"The only vulnerable part would be the observation deck, but that would be a tough target for an amateur pilot."
Quinn echoed Thompson's concerns about parcel and truck bombs. He said overall ground security at all Toronto commercial buildings needs improving.
PS. check out Dr. Jeremy Whitlock's new Canadian Nuclear FAQ item, "How are CANDU nuclear plants protected from terrorist attacks?" at http://www.ncf.ca/~cz725/cnf_sectionD.htm#terrorist