I don't think you can filter the binary load directly, but you can do a resident load of any table loaded, like
RESIDENT TableWithEmptyWorkStatus WHERE len(trim([Work Status]));
In above script snippet, WHERE len(trim([Work Status])) should only return non-empty work status.
You just need to replace the table name TableWithEmptyWorkStatus with the appropriate table name (ask your BI architect or inspect your tables using CTRL-T table viewer).
This will only filter one table, if you need to remove also records in other tables depending on the filtered table, you may need to do some additional steps (but it's hard to say, which ones. You probably need to describe the model a bit more detailed).
You could also consider creating a new qvw to binary load from by loading the original one, then filter some fields, and using the File->Reduce Data->Keep possible values function from the menu.
Hope this helps,