Excimer laser radiation changes the physical and optical properties of fused silica. These changes include laser induced absorption and density changes in the glass. Such effects may have an impact on the length of time for which optical elements made of fused silica can be used in DUV lithography systems. Corning Incorporated has recently developed and built a system for marathon testing of fused silica. The system consists of a 2000 Hz ArF laser and a specialized automated test bench. It allows the simultaneous testing of up to 10 samples under exposure conditions similar to the conditions expected in ArF lithographic exposure tools. First results of laser induced damage in samples exposed in this new system are presented.