to redouble their efforts in the urgent conclusion of a global chemical weapons ban. On the outer space question , Canada welcomed the establishment of an Ad Hoc Working Group to discuss this complex issue in greater detail. In support of the Conference on Disarmament 's deliberations , Canada has submitted a comprehensive study of existing international law relating to arms control and outer space. This survey identifies a number of important themes for examination if an international treaty preventing an arms race in space is to be successfully written . It also serves as an excellent example of the evolution and contemporary relevance of international law to the disarmament process. Canada is also working on the application of space-to-space remote sensing for arms control and disarmament purposes. Follow-up work on the application of space-to-ground sensing is also planned. While much of the world's attention is focused on nuclear, chemical and biological weapons, there is a fourth class of weapon of mass destruction , that is, radiological weapons . Although these weapons were identified by the United Nations JSM/plj A/C.l/40/PV.S 7 (Mr. ROche, Canada) almost 40 years ago, there is as yet no international agreement of any kind regarding radiological weapons. Since these weapons do not yet exist, the international community has a rare opportunity to prohibit a potentially devastating weapons system -in fact, to prevent even its conception -and to do so while the political obstacles to such a ban are at a minimum . There is then an urgent need to conclude a radiological weapons convention. Since 1979 the United States and the Soviet Union have been agreed on the basic text of a treaty to ban radiological weapons. Despite the fact that there has been little or no objection to the substance of the draft treaty, agreement has 