A baby that was found in a waste disposal site in Shipley has still not been identified six years after the discovery.
Night-shift workers found the new born baby girl in May 2011, when they were sorting through waste from across West Yorkshire.
An inquest in Bradford has heard that the search for where the rubbish had come from was narrowed to 36,000 homes and that letters were sent out in an attempt to trace the mother.
It is believed the baby was full-term and had died two or three days before she was found. However, a post-mortem has been unable to ascertain the cause of death.
Coroner Martin Fleming said: "It is never too late to come forward and do the right thing. We may never know the desperate circumstances that led to such a callous disposal."