"FEMA has 9,106 disaster assistance employees. Only 770 get federal health insurance."
The point is that FEMA uses "reservists" who are temporary employees and not eligible for FEHBP for most of its disaster response. It's rather like the Forest Service which has a similar deal for its firefighters. And FSA/ASCS which used to have a big slug of temporary field employees for summer compliance work. And the other variety is, of course, the county office employees who aren't technically Federal for some purposes, meaning they're usually excluded in counts of federal employees.