You also need to look at the counter parties in a lot of the union corruption, they were in dirty corrupt industries controlled by the mob. But at the same time, we don’t focus on that part of the story as much.

If you look at industries that had less corruption, you see less union corruption.

For me, the most memorable outcome of corruption was the Knox Mine disaster in 1959. UMWA officers, including District 1 president, had accepted bribes from company officials.

I hadn't ever read that the mob was tied to that corruption. However, a little searching turned up evidence of it.

    federal prosecutors had been on the trail of suspicious
    ties between coal operators and local officials of the
    United Mine Workers of America.
   
    That trail began at the infamous November 1957 "mob meeting"
    in Apalachin, N.Y., which was raided by federal investigators.
    Among the 60 or so men who attended were four Wyoming Valley 
    residents, including reputed crime boss Russell Bufalino and
    Dominick Alaimo, a committeeman with UMWA Local 8005,
    which represented workers in 10 mines, including 
    the Knox Coal Co.’s River Slope Mine in Jenkins Township.