In Brazilian law, slavery not only include forcing people to work against their will for little or no money. It includes failing to provide them with a safe and decent working environment. This broad definition has lead many employers with marginal operations a great deal of confusion, as this BBC documentary explains.
I think there is a good case for accepting this Brazilian definition of slavery. Many people who need money have no choice but to work for whoever will accept their labor. If the conditions are bad or unsafe, the employee has no choice. But it is not only unskilled quarry workers who are forced to work in uncomfortable conditions. How many of us work in hot kitchens with an abusive chef? How many in an airless office, afraid of becoming the next to fall to the bottom of the manager’s pecking order?