Can fiberglass doors be exposed to chlorine fumes without any harm (pool area)?
In general, we would not expect any problems, assuming that there is topcoat or paint on the door. The hydrochloric acid (muriatic) or some of the other chlorinated acids do attack the surface of the door skin irreversibly if concentrated enough (example brick wash-strength muriatic). The result is a surface that doesn’t stain evenly with the surrounding surface. However, once painted/topcoated, this shouldn’t be an issue.