When it was published in 1984, the Black report contained, together with its findings, a number of recommendations. One of these was the use of cytogenetic monitoring techniques with respect to the general public of West Cumbria and elsewhere. In the cytogenetics department at Sellafield, routine sampling of all new employees was carried out over a period of several years, with a view to collecting baseline aberration data, should this subsequently be needed in cases of suspected occupational overexposures. As a consequence, it was possible to undertake a survey comparing asymmetrical chromosome aberrations in young adults from Seascale, adjacent to the Sellafield site, with those of a control group from Whitehaven, situated some 10 miles to the north, who were 1-1 matched with respect to age, sex and smoking status.