Fibre Reinforced Plastics (FRPs) generally have greater advantages over conventional materials for their structural properties. However, the service life can significantly be shortened if the fibre reinforced plastics are exposed to adverse environmental conditions especially acid vapour, humidity and high temperature. In many chemical industrial plants in Australia and elsewhere fibre reinforced plastic gratings are used as structural components of stairs and passages where they are subjected to varying degrees of fluosilicic acid, a byproduct of the industrial manufacturing process. As currently no experimental data on the effects of fluosilicic acid on FRPs is available in the public domain, it is difficult to predict the service life of FRPs with some certainty. In order to understand the structural strength of fluosilicic acid exposed FRPs, an experimental study was undertaken. A series of specimens from various locations of a chemical plan in Australia were acquired and studied. Some new specimens (not exposed to acid, humidity and high temperature) were also studied to provide a benchmark for the comparison. The results indicated that the long time exposure to harsh environment and acid vapour can significantly deteriorate the flexural strength and service life of FRPs.