Following a notice received at the Ulster Museum from Edwards High Vacuum drawing attention to the fact that materials containing azides can be very dangerous if processed in a vacuum system containing copper, brass or bronze parts (with which azides can combine to form highly unstable explosive compounds), the author took steps to ascertain whether or not azides might be present in fresh biological specimens. Marine material and mammalian tissues could indeed contain azides, so the EF2 freeze drier was turned off. Azides are sometimes added in stabilizing agents, and detonations have been reported due to their presence in specimens thus treated. The situation is far more dangerous, however, since azides are naturally present in the specimens themselves. -- AATA