I'm surprised that it hasn't gotten any more media coverage than just the one TV station.
My recollection (backed up by some research I did after hearing this story), was that diesel exhaust doesn't contain nearly the amount of carbon monoxide that gasoline engine exhaust does. There's lots of other worrisome junk in it, but relatively little carbon monoxide. The fact that the affected controllers showed elevated levels of CO in their systems when they went to the hospital seems to me, to prove that they were indeed exposed to high levels of the fumes, and for an extended period.
Moreso than even exposing the controllers to that danger though, I think what's absolutely criminal
was to have people feeling such symptoms actually controlling traffic, where literally hundreds of lives were at stake..