  We consider gauge models in the causal approach and study one-loop
contributions to the chronological products and the anomalies they produce. We
prove that in order greater than 4 there are no one-loop anomalies. Next we
analyze one-loop anomalies in the second and third order of the perturbation
theory. We prove that the even parity contributions (with respect to parity) do
not produce anomalies; for the odd parity contributions we reobtain the
well-known result.
