The oil and smoke that spewed for months from hundreds of burning oil wells presented another exposure hazard not previously encountered in a war zone. Military personnel also had to cope with swarms of insects, requiring the widespread use of pesticides. High-powered microwaves were used to disrupt Iraqi communications, and though it is unknown whether this might have contributed to the syndrome, research has suggested that safety limits for electromagnetic radiation are too lenient.The Research Advisory Committee on Gulf War Veterans Illnesses (RAC), a VA federal advisory committee mandated by Congress in legislation enacted in 1998, found that pre-2005 studies suggested the veterans illnesses are neurological and apparently are linked to exposure to neurotoxins, such as the nerve gas sarin, the anti-nerve gas drug pyridostigmine bromide, and pesticides that affect the nervous system. The RAC concluded in 2004 that, "research studies conducted since the war have consistently indicated that psychiatric illness, combat experience or other deployment-related stressors do not explain Gulf War veterans illnesses in the large majority of ill veterans. "The RAC concluded that "exposure to pesticides and/or to PB [pyridostigmine bromide nerve agent protective pills] are causally associated with GWI and the neurological dysfunction in GW veterans. Exposure to sarin and cyclosarin and to oil well fire emissions are also associated with neurologically based health effects, though their contribution to development of the disorder known as GWI is less clear. Gene-environment interactions are likely to have contributed to development of GWI in deployed veterans.
U.S. forces detected, confirmed, and reported chemical agents; and U.S. soldiers were awarded medals for detecting chemical agents. The Riegle Report said that chemical alarms went off 18,000 times during the Gulf War. After the air war started on January 16, 1991, coalition forces were chronically exposed to low but nonlethal levels of chemical and biological agents released primarily by direct Iraqi attack via missiles, rockets, artillery, or aircraft munitions and by fallout from allied bombings of Iraqi chemical warfare munitions facilities.In 1997, the US Government released an unclassified report that stated:

"The US Intelligence Community (IC) has assessed that Iraq did not use chemical weapons during the Gulf war. However, based on a comprehensive review of intelligence information and relevant information made available by the United Nations Special Commission (UNSCOM), we conclude that chemical warfare (CW) agent was released as a result of US postwar demolition of rockets with chemical warheads in a bunker (called Bunker 73 by Iraq) and a pit in an area known as Khamisiyah. "Over 125,000 U.S. troops and 9,000 U.K. troops were exposed to nerve gas and mustard gas when the Iraqi depot in Khamisiyah was destroyed.Recent studies have confirmed earlier suspicions that exposure to sarin, in combination with other contaminants such as pesticides and PB were related to reports of veteran illness.