The use of optical fibers is of particular interest to the telecommunications industry, due to the many striking advantages over traditional copper lines. These advantages cannot be realized, however, unless the mechanical integrity of the fibers is guaranteed. Therefore, the fact that certain environments can have detrimental effects on the mechanical properties of optical fibers is of great concern. In this investigation, both zero stress aging tests and two-point bending static fatigue tests were performed. The environments tested include buffer solutions of pH 4, 7, and 10, sodium chloride solution, unleaded gasoline, wasp killer, and deionized water. Zero stress aging in these environments had varying effects on the fibers, ranging from mild to severe reductions in fiber strength. Aging in the high-pH alkaline solutions produced severe reductions in fiber strength, whereas aging in the wasp killer, gasoline, and low-pH acidic environments resulted in relatively mild reductions in fiber strength. The static fatigue tests produced similar results, with stress corrosion parameters ranging from 5.5 for the pH 10 environment to 25.4 for the unleaded gasoline environment. ‘‘Fatigue knees’’ were also observed in the NaCl and pH 7 environments. Because of the fatigue knees, the stress corrosion parameters dropped from 25.3 to 3.7, and 19.7 to 3.1 for the NaCl and pH 7 environments respectively.