A February 18, 2021 report titled "Resolving whether inhalation of depleted uranium contributed to Gulf War Illness using high-sensitivity mass spectrometry” by Randall R. Parrish and Robert W. Haley concluded that uranium from exploding munitions did not lead to Gulf War illness (GWI) in veterans deployed in the 1991 Persian Gulf War. The report was based on a study using high-precision multicollector mass spectrometry for the first time in such a study. Their report states their study found no differences in secretion of uranium isotopic ratios from those meeting the standard-case definitions of GWI and control veterans without GWI. The researchers say that the most likely remaining causes for GWI are widespread low-level exposure to sarin nerve gas released by the destruction of Iraqi chemical weapons storage facilities in January of 1991. This was possibly compounded by the use of anti-nerve agent medications and the use of pesticides to prevent insect-borne diseases in coalition forces.