Timothy Davies, nine, and Belinda Coffey, five, became infected through intravenous feeds at the Royal Manchester Children's hospital. Both leukaemia sufferers, they died in April 1994 after earlier undergoing chemotherapy.
The inquest at Salford heard they were infected by the enterobacter cloacae micro-organism after it colonised a sink trap. An expert believed when the mixer taps were turned on there was an aerosol effect which carried the organism to shelves where the feeds were stored.
Solicitors for both families said that legal action was being considered.