HSA is a Health Savings Account.
It is a very inexpensive medical insurance program.
My recollection is that it originated in South Dakota. Some states allowed them; some states did not allow them.
Over the years, the Federal government imposed more and more regulations and prohibitions against them. Nevertheless they were very popular.
The late Senator Ted Kennedy was very against them because he insisted on a British type of socialized medicine and forced many limitations on them. including a limit on the number of these accounts that would be allowed.
Presidential Candidate Donald J. Trump has proposed allowing them AND allowing interstate purchase, which had been the big stumbling block.
Indiana adopted the HSA for state employees and within a short time, they became very popular.