The radiation‐induced optical attenuation has been measured over a wide range of dose and time in state‐of‐the‐art step‐ and graded‐state60Co and pulsed electron irradiation. Results are reported for previously uncharacterized silica fibers containing dopants such as Ge,P,B,F,Tl, and Cs. At short times following the irradiation, fibers which contain Ge exhibit an extremely high attenuation that is not observed when these fibers contain P. Recovery is typically more complete in the silica core fibers than in the doped silica core fibers, which can have losses 25–1000 times the intrinsic loss 3 months after an irradiation of 105–106rad.