Some of the many symptoms include:
- Chronic fatigue
- Brain cancer
- High rates of infant mortality
Many causes have been suggested including:
- Anthrax vaccines
- Biological weapons
- Exposure to pesticides
- Exposure to scud missile fuel.
- Exposure to depleted uranium - the most likely and well-publicized
Langly referred to Gulf War Syndrome as "the agent orange of the 90s". A comment on the harmful effects of the defoliant which was used by the US Military in the Vietnam War and also caused considerable long-term damage to the health of servicemen (TXF: "E.B.E.").
In 1996, a militia leader associated with Alex Krycek told agents Mulder and Scully, while in federal custody, that Krycek said the "black cancer" (The Russian name of the Black Oil Virus) was used by Saddam in the Gulf War, and, in his words; "That's why they made those servicemen take all those pills." This possibly implies that the black oil and the pills were connected to the syndrome, although given the source of this information (Alex Krycek) it should perhaps be taken with a grain of salt.
Michael Kritschgau referred to the Gulf War syndrome when he met with Agent Mulder in 1997, and spoke of bioweapons used in the war and how his son, who came back from the Gulf War, was ill. (Although he never specifically cited the illness afflicting his son as Gulf War Syndrome, this seemed to be the implication.) Experiments conducted by the Millennium Group in the Gulf War, as well as the testing of the alien replacement Supersoldiers during the conflict, may have also played some role in the outbreak of the syndrome.