This is not good. Looking for more reports now.
Witnesses: 2 explosions heard near finish line of Boston Marathon - U.S. News
Witnesses: 2 explosions heard near finish line of Boston Marathon - U.S. News
Holy shit, just saw a video on Fox News where a huge plume of white smoke came out. Hope it's not some sort of chemical attack.
From the only picture i show that showed the smoke it looks like it might have used KNO3 as the Oxidizer, looking at the fireball and the smoke it resembles what you would see with KNO3.
Turned on FOX News soon as I saw the article in the thread OP.
Jesus Christ, this is frightening...