Lung cancer is the principle cause of morbidity and mortality from cancer in the developed countries, and several epidemiological studies show its relation to environmental exposure in urban industrial areas.1-3 Studies of this type are rare in regions of South America, where there are similar urban industrial areas to those in developed countries.

With the objective of contributing to this body of knowledge, we carried out an ecological study aimed at comparing the mortality from cancer among residents in a region of São Paulo State. Within this state, which is the most developed in Brazil, the region of Baixada Santista has the greatest general mortality from cancer, highlighting lung cancer as the leading cause of death among that population.4 Baixada Santista is a coastal region with bathing beaches, and had about 1 300 000 inhabitants in 1994 distributed among eight municipalities. It is separated from the capital of the state, which is located on a plateau, by a large mountain range. Four of its municipalities (NIP), located along the coast, are geographically and economically distant from the largest industrial port of Brazil, …