This is a pretty embarrassing paper, even by the low standards of the Harvard Business Review. A toxic worker is defined as anyone who takes too many pens, or someone who embezzles huge sums of money, or a sexual harasser, or a physically violent person, or a jerk, or... anyone retroactively deemed toxic by the manager who fired them.
All this time we thought Wal-Mart was firing people who were trying to unionize, turns out it was just far-sighted managers keeping a deadly contagion at bay. The Harvard Business Review inches ever-closer to the methodology of soviet psychiatry.