Alpe d'Huez said:Here's a video of the last kilometer. When you get to the site, you'll see the "laatste kilometer" link to the right of the window. Click it.
It looks to me like Petacchi was borderline at fault. You see it in the overhead shot. But it's a tough call, Van Avermaet may have caused it mostly on his own as he was the first guy to go down.
A bit of a warning: This is an awful accident. Robbie and Tom look like they were hurt pretty bad, a lot of asphalt burns and skin scraped away.