s security is a major issue. >> that's for sure. more misery tonight for washington, d.c.'s maligned transit system. four metro track inspectors and two supervisors have been fired for falsifying records after an investigation into a derailment in july. metro's general manager says it revealed a disturbing level of indifference, lack of accountability and misconduct. six more firings or suspensions are pending and 28 of the rail network's 60 inspectors are facing some kind of discipline. the u.s. is experiencing its worst mumps outbreak in ten years. mumps. >> it's scary to know something like that is around. >> reporter: parents feeling anxious after top u.s. health officials say they are closely monitoring the largest mumps outbreak in more than a decade. >> what we are seeing is a