A by-product of enriching uranium, depleted uranium has been stripped of most – but not all – of its radioactivity and is dense enough to pierce many types of armour. Despite the large body of scientific work on the subject, the UN has deemed it necessary to continue evaluating the health risks tied to the use of depleted-uranium shells while noting that no significant proof of health risks has yet been established. Despite the environmental risks, Hawn defends the UK’s decision to supply Ukraine with the munitions, saying that "there are a lot of depleted-uranium rounds sitting around in stockpiles"