(Pontiac, MI)  --  Pontiac Police say they have been caught off guard by a planned marijuana convention at the Silverdome this October.  Medical Marijuana Incorporated of California began selling vendor space this week for what is being called the Health, Wellness and Cannabis Expo.  A Web site promoting the event lists speakers and classes that participants can take part in over the three day gathering.  Michigan passed a medical marijuana law that went into effect 15 months ago, spurring growth in the related industry across the state since then.  The Silverdome was sold to a private company last year.  The event could attract 50-thousand visitors. 

-Metro Source