HOUSTON, Texas (KTRK) -- CenterPoint Energy had a data breach last month that affected more than one million customers, according to a filing with the Office of Texas Attorney General Ken Paxton.

On Wednesday, CenterPoint sent the following statement about the September data breach.

"CenterPoint Energy continues to investigate the cybersecurity incident disclosed last month actively. Upon learning of the issue, CenterPoint activated our incident response procedures and engaged external cybersecurity, forensic, and legal advisors to assist with the investigation. We continue to work with third-party experts to assess the scope of affected customer data to identify which customers will be provided notifications in accordance with applicable legal requirements. CenterPoint's delivery of electric and gas services has not been impacted and remains operational and undisrupted." In September, CenterPoint said it was aware of an online post by a third party claiming to have obtained customer information.