There are work VISA's also for people that have pending H1-B applications which is what I think OP meant. It would also explain why the employees weren't able to leave easily since the H1-B's are pending.
I worded it poorly. It's not a work visa for that case specifically, but I know there are work visa's for people who were students that have their h1-b applications in the lottery. I think non-stem students with masters get 2 chances while STEM students get 3? I work with a lot of immigrants so this is from what I understand. Sorry if I'm giving false info.
Yes, it's called "OPT", but is only for students on f-1 visas to get practical training in their areas of study. While it is temporary work authorization, it is not a work visa. There's a pretty huge difference in that h1bs offer a path to naturalization, whereas f-1 opt does not.