Researchers need dangerous viruses to develop vaccines and find cures. In 1985 workers at the same laboratory narrowly missed death when smallpox ampoules were found lying in a biscuit tin in a fridge - dated 1952 but still deadly. Porton Down holds germ weapon stocks to test protective suits. Gene changes in one country have potential to affect a whole continent, and ultimately the planet as a whole. Medical disaster is one thing, perhaps a highly infectious version of HIV, or a new cancer epidemic.
Environmental contamination is another.
Microbes can travel fast in dust, in water, on car wheels, on clothing, on animals. Risks regarded as very low by most experts - but price of serious error impossible to imagine. Already MPs calling for Gene Charter covering ethical and safety issues. Each new headline on gene research show how current legislation is running years behind the technology. However little point in controls if scientists can get on a plane and continue deadly experiments elsewhere.