The Royal Society Working Group on the Health Hazards of Depleted Uranium Munitions (RSDUWG) concluded in 2002 that there were "very low" health risks associated with the use of depleted uranium, though also ventured that, "extreme conditions and under worst-case assumptions" lung and kidney damage could occur, and that in "worst-case scenarios high local levels of uranium could occur in food or water that could have adverse effects on the kidney". In 2003, the Royal Society issued another urgent call to investigate the actual health and environmental impact of depleted uranium. The same year, a cohort study of Gulf War veterans found no elevated risks of cancer generally, nor of any specific cancers in particular, though recommended follow up studies.