Modeling electromagnetic propagation in the maritime environment is a key element in calibrating detection tools, for example in SAR imaging. This article presents a method to compute the propagation above a polluted sea surface. The latter is based on the parabolic wave equation solved with the split-step wavelet method. A hybrid method is also used to account for the sea surface. Indeed, here the sea spectrum is used to both generate random sea surfaces and compute a roughness parameter. The contributions of this article are twofold. First, we improve the calculation of the roughness coefficient in the hybrid method by accounting for the shadowing effect. Second, a stochastic strategy is developed to account for an insoluble oil slick, or pollutant, that covers part of the domain. Numerical tests in the S-band are provided to validate the method and highlight its advantages.