If a worker is left idle, the DL can use it immediately, as the governor obviously does not want it any more (except the situation where the governor left an order to let the worker sit idle in a city).
At the moment instructions for a worker are missing, the DL takes ownership of the worker. The worker is promoted from a provincial to a federal employee.
With this system, there will always be enough workers to clean pollution later on, for example, in each province, as this will be a provincial task to do ;-)
The governors should supply detailed worker info also right now, as also tile-usage information.
We should investigate why they dont follow their job-description ;-)