Exploitation of labor is the act of treating workers unfairly 
That sounds terrible! Does that type of practice still occur?
Exploitation of labour
Exploitation of labour (or labor) is the act of treating one's workers unfairly for one's own benefit. It is a social relationship based on an asymmetry in a power relationship between workers and their employers. When speaking about exploitation, there is a direct affiliation with consumption in social theory and traditionally this would label exploitation as unfairly taking advantage of another person because of his or her inferior position, giving the exploiter the power.
Karl Marx, who is considered the most classical and influential theorist
them poorer. Where the foreign supplier allows "de facto" exploitation of labor, domestic free-labor is unfairly forced to compete with the foreign exploited labor. To this extent, free trade is seen as an end-run around workers' rights and laws that protect individual liberty.
Some opponents of free trade favor free trade theory, but oppose free trade agreements as applied. Some opponents of NAFTA see the agreement as being materially harmful to the common people, but some of the arguments are actually against the particulars