To ensure that they did not profit unduly from the death and destruction caused by world war ii, manufacturers were subjected to:

The correct answer is a high excess profits tax

This meant that the more you earned the more taxes you would have to pay, so it didn't work that well for them if they earned a lot which meant that they couldn't just relentlessly exploit workers for maximum profit since the profit meant nothing. This was done to prevent people from profiting of of tragic events that came before.