<<10 years after they were furloughed. And if not hiring at that time they get another 4 years. If recalled and furloughed again....the clock resets @ 10 years.
Baja.>>
To clarify even more. Up to 10 years, you can choose to come back or not (so long as there is hiring going on), because of the merger they added 4 more years. However if you get recall in the '4 more years' part, there is no more choice. You accept recall when called, or resign on the spot.
That's the way the letter reads anyway.