Abstract

Abstract

The scientific literature on events involving the loss of containment of hazardous materials due to a natural event (known as na-tech events) is recent and limited in Brazil. Evidence was sought of the occurrence of these events in the coastal region of the state of São Paulo. The study identified fifteen na-tech events between 1940 and 2015, and showed that the events predominantly affected bodies of water. A method was then proposed to estimate the frequency of these events, relativizing them to the number of companies that generated them. Relativization allows the quantitative comparison among locations with different numbers of companies and the transfer of the estimated frequency among locations. The method also allows attributing less uncertain frequency estimates to na-tech accident hypotheses, favoring risk-based decisions. Consistent databases combined with the method allow the construction of na-tech hypotheses appropriate to the location during a quantitative risk assessment of an industrial facility.