Anyone who works in the manufacturing industry has doubtless noted this trend - companies fill their factories with agency workers either to make it impossible for their workers to organize, or to reduce the bargaining power of an existing union. If their workers go on strike or start making demands they don't like, they make a phone call to the placement agencies and have an army of semi-trained workers at their disposal, ready to step in for their full-time employees. These workers obviously have no protection at all - I have seen agency workers fired for getting hurt, for not looking busy enough despite doing their job well, for making safety complaints, and most frequently for no reason at all. It's very common for companies to retain agency workers until their contract with the union says they have to hire them, then let them go, then bring them back a week later for a fresh "temporary" period. This is increasingly the direction multinational capitalism is heading in - we are supposed to be grateful for unpaid internships because they provide "valuable experience," for even having that unprotected $11/hr job breathing in cancer at a factory. Temp workers are renting themselves to a middleman who in turn rents them out to a capitalist, and at every auto plant I've worked at in nearly ten years, new full-time employees are only hired through the agency, after a temp period.