HHS OCR report ยท 2025
Onsite Mammography data breach
OCR report facts
- Covered entity
- Onsite Mammography
- Entity type
- Business Associate
- State
- Massachusetts
- Individuals affected
- 357,265
- Submission date
- Apr 21, 2025
- Type of breach
- Hacking/IT Incident
- Location of breached information
- Business associate present
- Yes
- Status
- Archive (closed)
OCR description
Onsite Mammography, the covered entity (CE), reported that an employee was the target of an email phishing scheme that impacted the protected health information (PHI) of 357,265 individuals. The PHI involved demographic and treatment information. The CE notified HHS, affected individuals, the media, and provided substitute notice. In its mitigation efforts, the CE implemented additional administrative and technical safeguards.
Text as published on the HHS OCR breach portal.
Frequently asked questions
How many people were affected by the Onsite Mammography data breach?
The report to HHS OCR lists 357,265 individuals affected.
When was it reported to HHS?
It was submitted to HHS OCR on Apr 21, 2025.
What type of breach was it?
The OCR portal lists the type of breach as Hacking/IT Incident, with the breached information located in: Email.
Is the investigation still open?
No. The report is in the OCR portal archive, which holds reports where OCR has closed its review.
Is a breach notice letter from Onsite Mammography legitimate?
This site cannot verify letters. Check the sender against the organisation's official website and the HHS OCR breach portal, and avoid calling numbers or clicking links only listed in an unexpected message. See our guide on what to do after a data breach notice.
Source: HHS OCR Breach Portal, OCR export October 2026. Network USA is not affiliated with HHS or Onsite Mammography.