Development of nanotechnology must be undertaken with care to avoid accidents; once a nanotech-based manufacturing technology is created, it must be administered with even more care. Irresponsible use of nanotech could lead to black markets, unstable arms races ending in immense destruction, and possibly a release of gray goo. Deliberate misuse of the technology by inhumane governments, terrorists, criminals, and irresponsible teenagers could produce even worse problems--gray goo is a feeble weapon compared to what could be designed. It seems likely that research leading to advanced nanotechnology will have to be carefully monitored and controlled.