05/18/2012 09:11 am ET Updated Jul 18, 2012

U.S. Car Companies on Cruise Control While the Amazon Burns

Brazil is on the move. From the soaring skyscrapers of Sao Paulo to the manufacturing center of Manaus, this country is taking the 21st century and running with it. The nation hosts the soccer World Cup in 2014, the Olympics in 2016 and the Rio + 20 Earth summit in just a few weeks time. These events signify platinum membership on the world stage, proof that Brazil is arriving as one of the world's true superpowers.

But not everything here is shiny and new. In the heart of the Amazon, a scandal is unfolding which threatens the reputation of both the Brazilian president and some of the biggest car companies in the world. In the Carajas region of Northern Brazil, hundreds of remote charcoal camps are hidden from view, some visible only by airplane. Vast rows of mud furnaces line up like ant hills, burning rainforest wood and poisoning those who stoke them with particulates, asthma and disease. Workers are lured to the camps with the promise of good wages and then told to pay off huge (and unjustified) debts as soon as they arrive, or are simply not paid at all. Brazil officially banned slavery a little over 125 years ago, but the evidence of forced unpaid labor here shows that the country has not yet eradicated this terrible legacy.

Only a tiny fraction of this charcoal ends up in barbeques. In fact, the vast majority is used by industry, including Brazilian companies who shovel it into giant blast furnaces to convert raw iron ore into 'pig iron' -- a key ingredient in the steel-making process. This is then exported from Brazil in giant cargo ships like the one Greenpeace is blockading right now. 80% of Brazilian pig iron goes to the USA and is bought by cast-iron foundries and steel mills like the Severstal plant in Columbus, Mississippi. The resulting steel is used by some of the biggest players in the game -- companies like Ford, GM, BMW and Mercedes.

Greenpeace Brazil spent the past two years investigating this problem and has produced a new report, Driving Destruction in the Amazon, which contains evidence designed to put a stop to this inhumane and antisocial trade once and for all. Our activists are hanging off the anchor chain of a cargo ship here in Sao Luis to make sure the issue is not swept under the carpet, which is what happened six years ago when the scandal was first brought to light. They've been occupying the narrow chain for over 80 hours, an impressive feat of endurance but nothing in comparison to the suffering borne by the rainforest communities at the center of this trade.

It's not good enough for the U.S. car industry to claim that the problem is too far removed from them, that they have little control over their massive supply chain. Companies like Ford claim to have 'zero tolerance' for slave labor, but if Greenpeace can find this evidence then they can too. By insisting that their pig iron suppliers are free from deforestation and slavery -- and holding them to account -- they can change the game almost overnight. And President Dilma, too, can boost her environmental and judicial reputation by acting on this before the summit opens in a month's time. Anything less would be a step backwards for a country that is fast becoming a leading light on the world stage.