Since 2003, measurements made by Green Audit in Fallujah, Iraq 2003, Lebanon 2006 and Gaza 2008 have provided unequivocal evidence of Uranium residues which show anomalous Uranium U-238/U235 isotope signature ratios. Results from independent laboratories in Europe and the UK, using different techniques, revealed the presence ofen riched Uranium in biological materials and environmental samples including soil, bomb craters and air (as recorded in vehicle air filter dust). More recently, 2021 results published in the Journal Nature, show that Uranium enrichment levels in background samples from Gaza have been increasing markedly since 2008. Since enriched Uranium is an anthropogenic substance which does not exist in nature, the question arises as to the source, in the weapons employed by the USA (Fallujah) and Israel (Lebanon, Gaza). It is proposed that the only logical answer is that a Uranium-based weapon exists that produces U-235 by neutron activation and has been deployed. Such a weapon must be some kind of neutron bomb.