Since no DUmmies are stepping up to the plate, my recommendation would be go to the boss with a solution for the issue. Tell them that your workload has been really heavy, explain what you have tried to do resolve the issue and meet deadlines, then request overtime. If the workload is really that heavy, the boss probably knows it, and will respect him for trying to get more done. My suggestion would be to do it ASAP if a couple months of not meeting deadlines has passed though, that it reaching into the irresponsible category.