Health insurer Centene on Tuesday said the loss of six hard drives with health info on 950,000 beneficiaries was a result of an employee error. The drives are still missing.

“The incident resulted from an employee not following established procedures on storing IT hardware,” the Fortune 500 company said in a financial statement released Tuesday. “While we cannot estimate the impact with certainty at this time, the company does not expect the impact of the incident to have a material effect on its future growth opportunities, financial position, cash flow or results of operations.”

[Also: Centene loses health info on 950,000 beneficiaries]

Centene is in the midst of a $6.8 billion merger with Health Net. The deal is expected to close February 1, Centene said in Tuesday’s statement.

The health insurer announced total revenues for 2014 of $22.8 billion. Preliminary financial results for the 2016 fiscal year, assuming a Feb. 1 closing date, are revenues in the range of $41.2 to $42 billion, Centene said.

On Monday, Centene said it has lost six hard drives that were a part of a data project using laboratory results to improve the health outcomes of members, according to CEO Michael Neidorff.

The St. Louis-based company, which offers managed Medicaid plans to uninsured or underinsured people, said it did not believe the information had been used inappropriately. Centene said it had launched an internal search and had begun 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, member IDs and financial or payment data, on people who received laboratory services between 2009 and 2015. It promised to offer free healthcare and credit monitoring to affected customers.

Twitter: @SusanJMorse