2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/51822We show that, contrary to common belief, the propagation of a spin-2 field in an electromagnetic background is {\em causal}. The proof will be given in the Fierz formalism which, as we shall see, is free of the ambiguity present in the more usual Einstein representation. We shall also review the proof in this latter representation.6 pages, RevTex4, minor changes following hep-th/0304050 and gr-qc/0304041, conclusions unchangedHigh Energy Physics - Theorytext