Staff have been disciplined at Westminster Homecare after an elderly resident at Jill Jenkins Court in Whipperley Ring, Farley Hill, was left on a bus overnight.
The driver of the bus, Susan McLaughlin, 44, was cleared of neglect at Luton Crown Court last month.
Dementia sufferer Joan Cook, 88, spent 14 hours trapped in the vehicle.
No-one from Jill Jenkins Court noticed she was missing.
A Westminster Homecare spokesperson said staff did not follow correct procedures and escalate their concerns to external sources such as Mrs Cook’s family, the council or police.
She added: “Staff involved have been disciplined and/or dismissed as appropriate and additional policies and procedures have been implemented to ensure this type of situation never happens again.”
A council spokeswoman apologised for the “inexcusable” occurrence and said: “We immediately reviewed the communication, missing person and safeguarding procedures at both Luton’s privately-run extra care sheltered housing schemes and made clear where improvements are needed.
“We are very sorry this shocking incident happened and have done everything possible to ensure that the people of Luton can continue to have confidence in the service.”