The IRS office of chief counsel has held that private citizens working for contractors in a Combat Zone must pay taxes on all of their income. The income tax exclusion for combat pay only applies to members of the Armed Forces and not to civilian contractors and employees.
They can qualify for the physical presence foreign earned income exclusion of $91,400 (for 2009) if the live and work in the foreign country for a full 12 month fiscal year and are present in that foreign country for 330 days out of that 12 month fiscal year period. This is called the "physical presence test." It is almost impossible for a private employee or contractor working in a combat zone such as Iraq or Afghanistan to qualify as a bonafide resident in order to secure the foreign earned income exclusion. AM2009-003
