Over 200 people received an email from a Kent care agency containing the personal details of elderly and vulnerable people.
Codes for key safes, names, addresses and telephone numbers of more than 100 people under the care of Kent Social Care Professionals (KentSCP) were sent to care workers and relatives of those in the care of the agency on August 11.
The information leaked belonged to people from New Ash Green, Swanley, Hextable, Northfleet, Gravesend, Dartford, Meopham, Istead Rise, Bexleyheath, Sidcup, Greenhithe, West Kingsdown, Longfield and Slade Green.
Cathy Hadlow, compliance manager with KentSCP said: "We were immediately aware of what had happened, and began taking steps to inform the people whose data had been compromised, and to get the key safe numbers changed. Some Service Users were contacted directly, for some we contacted family members, or we sent Care Workers to explain in person and change the codes, as appropriate.
"By the end of the day that the email was sent, the majority of the numbers were changed, or family members informed.
"As matters stand, apart from five instances of people who have for various reasons refused – and we have to respect their personal choice – all of the key safe numbers affected are either changed or the keys have been removed."
Those who received the email were sent a follow-up email asking that the original email be deleted.
KentSCP's emails have been be disabled while the incident is investigated and staff will undergo an internal training session on Data Protection.
If you or a relative have been affected by this call the newsroom on 01689 885734 or email: firstname.lastname@example.org