In this article in The Independent, Daniel Howden states:
More than 1,000 "enslaved" workers have been released from a sugar cane plantation in the Amazon following a raid that has highlighted the dark side of the current ethanol boom.
Brazilian authorities said that the workers in the northern state of Para were being forced to work 14-hour days in horrendous conditions cutting cane for ethanol production.
Police said the raid was Brazil's biggest to date against debt slavery, a practice reminiscent of indentured labour where poor workers are lured to remote rural areas, then pushed into debt to plantation owners who charge exorbitant prices for everything from food to transportation.
Not that much different than John Steinbeck's Grapes of Wrath in another time and place.