I just saw a report about a UA flight at SJC airport about 20 minutes ago on TV. The content was sketchy but what I have learned was that this was an A320 plane that originated in ORD and according to some reports it seems that a passenger got up and started to spread a "powdery white stuff" at passengers.

Unfortunately I did not see the whole thing and was not able to find anything on the internet. Does anybody know more about this incident?