The Chickasaw Nation Department of Health (CNDH) is notifying patients of a privacy incident involving personal health information of individuals visiting the Chickasaw Nation Medical Center Emergency Department in Ada, Oklahoma.

What Happened?
CNDH became aware of an individual employee accessing personal health information without authorization, April 22, 2026.  An investigation was promptly initiated, and immediate measures were taken to halt unauthorized access and identify individuals who could be affected.  

The investigation determined the access was the result of one individual employee acting in violation of CNDH policies between Dec. 1, 2025, and April 22, 2026. 

What Information Was Involved?
The personal health information compromised in the electronic data was limited to patients who visited the Chickasaw Nation Medical Center Emergency Department from Dec. 1, 2025, through April 22, 2026. Specific information that may have been accessed included full name, age, date of service, tribal affiliation, reason for visit and other clinical information such as lab and radiology orders.  CNDH does not have evidence that full social security numbers were compromised in this incident

What You Can Do
Though we have no evidence that your identity is at risk as a result of this incident, the following are steps you may choose to take: 

• Register a fraud alert with the three credit bureaus listed here and order credit reports:​
  • Experian: (888) 397-3742; Experian.com; P.O. Box 9532, Allen, TX  75013
  • TransUnion: (800) 680-7289; Transunion.com; Fraud Victim Assistance Division, P.O. Box 6790, Fullerton, CA 92834-6790
  • Equifax: (800) 525-6285; Equifax.com; P.O. Box 740241, Atlanta, GA  30374-0241
• Monitor account statements, Explanations of Benefits and credit bureau reports closely.
• Contact the Consumer Protections Agency; oag.ok.gov/consumer-protection-unit1.

For More Information
We take the privacy and security of your personal health information very seriously and deeply regret any inconvenience this may cause. If you have any questions, please contact the Privacy and Security Office at (580) 272-2706 or by mail at:

Chickasaw Nation Department of Health, Privacy and Security Office 
1925 Warrior Way
Ada, OK 74820.