. >> reporter: for more than a year cbs news has followed walter tamosaitis and donna busche, two high level managers who uncovered major design flaws at the handford waste treatment plant which they say could lead to a radioactive explosion. >> nuclear waste would go into the ventilation system in the buildings, and if the explosion was severe enough, would be released to the public. it would be very similar to the explosions you saw at fukushima. >> that's how bad this could be. >> that's how bad it could be. >> reporter: walter tamosaitis was fired last october. >> you think it was retaliation? >> retaliation, clear retaliation. >> it sent a resounding message to me. >> reporter: and you feel are you next to go. >> absolutely, i do. >> reporter: she was right, donna bushe was fired last month. >> summarily removing me from the project sends a clear and present message to the employees that if you speak up if you stand up, you will be terminated. >> these were top employees with many degrees, that were valued until they raised concerns. tom carepenter with the watchdog group handford

walter tamosaitis who testified before the sub committee in 2011 also claims to have suffered professional damage, including termination, after raising major nuclear safety issues. these individuals and many more who have chosen to remain anonymous have brought their concerns forward to their employers, to d.o.e. and to congress. i don't think anyone wants to be a whistle blower. reporting your colleagues who may be your friends for actions that look like waste fraud abuse or others isn't an easy decision for most people. and life after you've blown the whistle isn't easy either, but the job that whistle blowers do is tremendously important and valuable. that's why when courageous men and women feel compelled to speak out, we do not want to silence them. we want to give them a process that allows them to report that without fear of retaliation. before the hearing began, i took the opportunity that hear from miss busche and dr. tamosaitis. i also heard from mr. carpenter who represents many more workers. they describe an atmosphere in which they and other individuals face severe real grags

walter tamosaitis who testified before the sub committee in 2011 also claims to have suffered professional damage, including termination, after raising major nuclear safety issues. these individuals and many more who have chosen to remain anonymous have brought their concerns forward to their employers, to d.o.e. and to congress. i don't think anyone wants to be a whistle blower. reporting your colleagues who may be your friends for actions that look like waste fraud abuse or others isn't an easy decision for most people. and life after you've blown the whistle isn't easy either, but the job that whistle blowers do is tremendously important and valuable. that's why when courageous men and women feel compelled to speak out, we do not want to silence them. we want to give them a process that allows them to report that without fear of retaliation. before the hearing began, i took the opportunity that hear from miss busche and dr. tamosaitis. i also heard from mr. carpenter who represents many more workers. they describe an atmosphere in which they and other individuals face severe real grags