In November 1991, almost three years after a bomb blew up Pan Am Flight 103, officials heard concerns from Dr Rodney Murray, senior medical officer of the Search and Rescue Dog Association, after the death of a rescue dog from liver and other tumours. Depleted uranium (DU) weights were used as ballast in the plane's tail. A memo said Murray was concerned that "symptoms of the dog and its subsequent death may be the result of exposure to harmful agents" from the wreckage.
The memo said: "If this were so there might be implications for human health. Anecdotal information provided by Murray suggests that three other dogs out of the 50 or so employed in searching the Lockerbie crash site had died from various causes."
A second memo said Murray referred to uranium and other nuclear sources on the plane and referred to unspecified areas of the crash site which were unapproachable and guarded by armed American personnel.
Scottish Office health official Hector MacKenzie asked colleagues for information.
In response, a civil servant at Her Majesty's Industrial Pollution Inspectorate said most of the DU had been recovered, and the rest was buried "at depth following the impact because it is extremely dense". MacKenzie let the matter drop soon afterwards.