Power Window problems of the 1999 Toyota Sienna

I was driving at approximately 35 mph and the left, rear window blew up. The glass spewed all of the back of the car. Luckily, I had just dropped off my kindergarter at school and no one was injurred. I called the police and he said it didn't look like anything hit it. He said that sometimes when the window slightly opens like this one does when I push the button it makes the window weaker. I didn't have the window opened and if that vent makes the windows explode, they shouldn't be installed in the cars where children and others can be hurt. If anyone was sitting in the back, they could've been seriously wounded. Is there any other reports of this happening with back auto windows in Mini vans? now I'm afraid the other side window is going to blow and hurt someone. Dt.