Junior surgeons at Massachusetts General Hospital have been working too many hours in violation of patient safety rules, according to the Accreditation Council for Graduate Medical Education that is threatening to put the hospital's surgery training program on probation. The Accreditation Council cited the hospital because a significant number of its residents were exceeding hour limits and working seven days straight. The organization believes these workloads contribute to fatigue-related mistakes, and has given the hospital until Aug. 15 to fix the problem.