Health insurer Centene Corp. on Monday said it has lost six hard drives containing the health information of about 950,000 beneficiaries.

The St. Louis-based company, which offers managed Medicaid plans to uninsured or underinsured people, said it did not believe the information has been used inappropriately.

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“Out of abundance of caution and in transparency, we are disclosing an ongoing search for the hard drives,” CEO Michael Neidorff said in a regulatory filing with the Securities and Exchange Commission. “The drives were a part of a data project using laboratory results to improve the health outcomes of our members."

Centene said it has launched an internal search and has begin to notify members whose information is on the missing hard drives.

The company said the hard drives contained personal health information, such as social security numbers and member IDs on people who received laboratory services between 2009 and 2015. No financial or payment data was accessed.

Centene said it will offer free healthcare and credit monitoring to affected customers.

The publicly-traded company is slated to acquire Health Net, which also deals in managed Medicaid, in a $6.8 billion deal.

Twitter: @HenryPowderly