It's not known how many, if any, Canadian vehicles are affected.
Below is an E-mail I received directly from Heather, my contact at GM Canada (unedited):
The suspension safety recall involves certain vehicles built at the General
Motors assembly plant in Moraine, Ohio.
Under certain circumstances it may be possible for the front lower control arm to fracture, resulting in separation of the front lower control arm from the frame. A separation could result in loss of vehicle control and a crash could occur without prior warning.
General Motors has recently learned of this condition and we have dedicated the time since then to determining the extent of the condition and its effect on vehicle performance. We now believe that the best course of action is to communicate with our customers and to help prevent any potential incidents while GM finishes its investigation of the condition. We will address remedying the condition after completing our investigation.
We stopped shipping vehicles from the plant as of Monday, April 2. General Motors will not manufacture any new TrailBlazers until this condition is completely remedied. If your vehicle is already at a dealership, you should know that General Motors has sent dealers a notice that they should not deliver vehicles to customers, due to the existence of a safety defect. The dealers will be notified when General Motors has developed an appropriate repair procedure and when parts become available. At that time, the dealer will repair the vehicle and notify you that the repair has been completed.
If you require further assistance, do not hesitate to e-mail us back at http://www.gmcanada.com.