Yes. He blew out his employees, and backfilled with H-1B's and "contract employees" who had no benefits, only contracts with human-slavery outfits -- what I call the "secondary employment" market, viz., jobs nobody would take if they could avoid them, but are "arranged" for them by the captains of the people-squashing industry.
Garry Trudeau (Jane Pauley's hubby) lampooned Welch extensively in his "Doonesbury" comic strip for his predatory employment practices. Welch probably has a museum-lit bust of Henry Clay Frick in his office.
A woman of my acquaintance had a contract joblet with a GE subsidiary. Or rather, she had a job with the slave contractor, which had a contract with the GE sub, GE Information Systems (GEIS). Anyway, she was expected and told she was expected to put in a certain number of "casual overtime" hours weekly (no ticket, no pay, no nothing) -- or else. Clearly illegal, but GE insulated itself using contractual relationships, relying on the deference courts pay even to contracts that are unequal and manifestly coercive, and the contractor assumed the risk of federal Wage and Hour Division enforcement actions.
It entirely depends on how the job is classfied by the US Dept. of Labor.
It's only illegal for employees classified as "non-exempt" employees such as factory line workers who must be paid for overtime.
For "exempt" employees (exempt from the Fed wage & hours laws) such as professional and management employees, casual (unpaid) overtime is perfectly legal and very common.
I did it for over 30 years, but by the same token, I never punched a time clock in those years and didn't get docked pay for less than 40 hours either when I had a doctors appointment or such. I was only asked to get my assignments done and often it would take more than 40 hours for that.
There were a number of occasions when it was far more than 40 hours, and in some of those cases, they did pay overtime while in others, I was told to take comp time to make up for the extra hours that I worked.
Bottom line: It is not illegal.