Rare and toxic, beryllium can do serious damage to your lungs. Presenter Laurence Knight explores whether and how we can make use of this metal safely. Prof Andrea Sella of University College London explains why beryllium's surprising scarcity is the very reason it can be so harmful to the body. Gianna Palmer reports from the Hanford nuclear site in Washington State on this chemical element's intimate and poisonous history in the US nuclear weapons programme. And we hear from IBC Advanced Alloys, a company that claims to have a novel, cheap - and safe - way of producing aeroplane parts out of beryllium-aluminium.