Johns Hopkins Bayview Medical Center is notifying 3,182 patients that some of their personal health information may have been exposed after a hospital worker uploaded a spreadsheet of patient data to an outside artificial intelligence tool that the hospital had not approved.

The hospital said it discovered the problem on September 21, 2026, during an internal review. According to the report, the upload took place that same day.

The spreadsheet covered patients who were admitted and treated at the hospital between May and September of this year.

Information that may have been exposed includes patient names, admission and treatment dates, medical record numbers, account numbers, the department that provided treatment, medications given and the names of providers.

The hospital said the spreadsheet did not contain Social Security numbers, financial account information or other identifying information.

According to the hospital, the worker deleted the prompt, the conversation thread and the document from the AI tool's history, and the hospital asked the company behind the tool to delete the data as well. The report did not name the AI company.

The hospital said it is strengthening its policies and training, restricting the use of unapproved apps and AI tools, and retraining staff on the tools that are approved.

Letters to affected patients began going out in the mail on October 22. The letters explain how to sign up for 12 months of free credit monitoring through Experian IdentityWorks.

Patients with questions can call a toll-free line at 1-833-931-7766 and give engagement number B174716. The line is open Monday through Friday from 8 a.m. to 8 p.m. Central time, which is 9 a.m. to 9 p.m. in Baltimore.

Independently written by the BJL Newsroom based on reporting from WMAR-2 News.