One of the reasons the post-hurricane flooding in Louisiana is so dangerous is because of Cancer Alley -- the string of petrochemical operations that line the Mississippi River in largely poor and black communities from New Orleans to Baton Rouge. They've turned the lower gulf into one of the most polluted and blighted parts of the country, which many believe is to blame for the rash of deadly illnesses plauging residents in the area.

The radio show Living on Earth did a good piece on this with Darryl Malek-Wiley, a legendary environmental and social justice activist in Louisiana. I was once on a bus with Darryl as he gave a "toxic tour" of Cancer Alley, guiding us through the grim surroundings of planned poverty and poisoning at the hands of Big Energy.

He will be the first to tell you there was nothing "natural" about Katrina's aftermath -- it was the exclamation point to decades of systematic racism and exploitation in the region.

You can check out this important show here.