During World War II, there were strict price and wage controls to prevent inflation. There was also a labor shortage since all the men were overseas fighting. Employers who wanted to attract extra workers started offering fringe benefits like health care being one of the main ones. At first, it was ambiguous whether or not these fringe value of these fringe benefits would be taxed as income for income tax. But after the war, there was a decision made that they would not be taxed.