Radon is a radioactive gas that emanates from rocks and soils and tends to concentrate in enclosed spaces, with soil gas infiltration recognized as the most important source of residential radon. Radon is a major contributor to the ionizing radiation dose received by the general population, and recent studies on indoor radon and lung cancer in Europe, North America and Asia provide strong evidence that radon causes a substantial number of lung cancers in the general population.  Researchers from the European Centre for Environment & Human Health (part of the Peninsula College of Medicine & Dentistry [United Kingdom]) have detected a connection following analysis of data on radon exposure and skin cancer cases from across southwest England. The study, which looked at small geographical areas across Devon and Cornwall, builds upon a similar study conducted 15 years ago. Whereas both radon levels and skin cancer incidence in the southwest are amongst the highest in the UK, the study found no association between household radon levels and malignant melanoma, or the most common form of skin cancer basal cell carcinoma. However, a link was found between areas where high radon concentrations are found and a particular type of non-melanoma skin cancer called squamous cell carcinoma.  Writing that: “This ecologic study suggests that environmental radon exposure may be a risk factor for squamous cell carcinoma,” the study authors urge that: “Further study is warranted to overcome ecologic design limitations and to determine whether this relationship is generalizable to national and international settings.”