That's what we call a "fired if you do, fired if you don't" kind of situation.

That would constitute arson, and arson is a crime. It's not legal to procure criminal behavior, whether by an employment contract or by other coercive means.

Technically, arson is burning down someone else's property. It's not a criminal offence to burn down a house you own, though it is likely a non-criminal fire code violation.

I don't think that's right. For example, in the California Penal Code,

"A person is guilty of arson when he or she willfully and maliciously sets fire to or burns or causes to be burned or who aids, counsels, or procures the burning of, any structure, forest land, or property." [1]

The incendiary's ownership or not of the property doesn't matter.

[1] https://leginfo.legislature.ca.gov/faces/codes_displaySectio....

From your link:

  For purposes of this paragraph, arson of property does
  not include one burning or causing to be burned his or
  her own personal property unless there is an intent to
  defraud or there is injury to another person or another
  person’s structure, forest land, or property.

Thank you - I agree it turns on mens rea. Burning one's own property can be criminal arson, depending on intent or result.

Just as you'd expect. Whether the property in question are books you own, or a shed, or your entire house it's your property and it's not a crime to turn your property into a bonfire so long as doing so doesn't break other criminal laws.

As that would be arson I have some doubts it goes that far. It would be a very interesting whistleblowing case I suspect.

But the whistleblowing would be for "trying to force an employee to commit arson", not for firing them.

It doesn't seem to be that simple in most US jurisdictions: https://en.wikipedia.org/wiki/At-will_employment#Public_poli...