He's covering the BP oil spill disaster for Greenpeace, and he narrates a slideshow of his images here on The Guardian. "It's really sticky, gooey stuff... The problem is the oil is getting mixed in the water, is getting ... in the food chain, and is going to end everywhere."
He describes not only what he sees, but how the authorities are making things difficult for journalists. "It's important not to let the attention fall," he says. If the Exxon Valdez was like a stroke, this spill is like a cancer. "This one is really eating the whole ecosystem little by little, and it's difficult to show that."
More of his work here.