FRONTLINE/World journeys to the Amazon and the remote rainforests of Brazil, where several major American companies are on the hunt for ways to capture an increasingly valuable commodity — carbon — as Congress considers new legislation that would force them to pay for their pollution.

FRONTLINE/World journeys to the Amazon and the remote rainforests of Brazil, where several major American companies are on the hunt for ways to capture an increasingly valuable commodity - carbon - as Congress considers new legislation that would force them to pay for their pollution. In a joint project with the Center for Investigative Reporting, reporter Mark Schapiro visits a number of demonstration projects that help explore the promise and potential pitfalls of this new trade in trees. Also in this hour: On the two-year anniversary of the immigration raid at a kosher meatpacking plant in Postville, Iowa - one of the largest workplace raids in history - a look at the human impact of the crackdown on both sides of the border. And, in Uganda, a new approach to the threat of diseases that cross the species barrier.