The federal "coverage" is a joke to non-FT fed personnel. They are only covered while on duty and for a very,very brief time after they are decom'd from an event. Until two years ago if you were injured while working for the feds your w/c was based on the fed salary for the year NOT your FT job's salary. In other words....screwed.
Regarding this issue, the feds and other insurers are very slow to make a "determination" IF the illness is "potentially" related to ground zero. I know of a mid-40 y/o Paramedic (not locally) who worked in NY at that time and stayed at the site for nearly 3 months. 7 years ago he left NY for South Florida. The same year he developed "emphysema type" respiratory issues. He is a non-drinker, non-smoker, grew up in a non-smoking environment, no other medical hx and/or family respiratory illness history. Since his onset, he has paid out a significant amount of his own money for tx, fighting the City of NY, State of NY, Feds and his insurer every step.