[benjvi]

You make a good point, but perhaps its not so black-and-white as that. If the OP has no real relationship with more senior management, then it is indeed a risky move to take it there. But we don't have very much information to say what the relationships are. It may very well be possible to bring this up intially in a non-accusatory, informal sort of way.

And, just in case you are around when the shit does hit the fan, then, surely, you would want to have some evidence to show that you pushed to take action to correct the problems you saw. There's no mention even of any documentation of their concerns, which surely should be priority number one. I have seen similar (if less extreme) cases where developers knew about problems that no-one acted on. And guess what? When the impact from the problems became apparent, they took the blame, because they had no evidence to exonerate themselves. If the culture of the upper management is not as bad as you assume, then you will end up looking like the bad guy by keeping quiet.