Cincinnati-based grocery chain Kroger is investigating a recent hack that affected a small amount of its pharmacy customer data, including healthcare and social security information.

“At this time, based on the information provided by Accellion and its own investigation, Kroger believes that less than 1% of its customers, specifically customers of Kroger Health and Money Services, have been impacted,” the company said in a Friday statement, adding it would contact current or former clients who may have been compromised.