A third baby was left with significant injuries in an incident in a birthing suite at Bankstown-Lidcombe Hospital in Sydney, Australia more than two years ago, Australian media reports.
The wall-mounted units which provide oxygen at the hospital were installed after a newborn was injured in January 2014, when an oxygen bottle ran out in a birthing suite as a baby was being resuscitated.
The case led the hospital to install the oxygen wall units to allow a constant flow of the gas to theatres.
The revelation comes after the death of baby John Ghanem on July 13 of this year, after he was accidentally administered nitrous oxide instead of oxygen through an incorrectly installed machine at the hospital.
Another child, a baby girl, born in June, was also given the poison and remains in a critical condition with significant brain damage.
The error was identified last Thursday, after a paediatrician raised concerns over the death of the baby.
An oxygen machine in one of the hospital's theatres was incorrectly installed and certified by gas supplier.
A review of Bankstown-Lidcombe Hospital's records has found no other babies received the incorrect gas, the NSW Australian Health Minister told media.
The hospital has shut down the operation theatre with the faulty machine, while the hospital's seven other theatres have been checked and deemed safe.