The objective of this article is to assess polymeric insulators subjected to polluted environments. The case studies were conducted on polymeric insulators installed on 500 kV lines. All analyses were carried out with computer simulations, employing finite element methods to calculate the voltage distribution on the surface of the insulators, and the Rizk model in order to assess the discharge voltage of these components, with deposits of pollution layers. The article also presents a number of problems that occur with polymeric insulators, and which have led to the failure of these units, causing great concern to the electricity sector regarding the system. Important conclusions have been obtained, which contribute to the assessment of these events.