Treasuer Denise L. Nappier said Thursday that JPMorgan Chase & Co. was too slow to disclose a security breach that potentially compromises the personal data of 465,000 debit cardholders, including about 14,000 in Connecticut.

The state uses the debit cards for tax refunds, unemployment benefits and child support payments that flow through the Department of Children and Families. Reuters reported the breach Wednesday, saying that the bank discovered in September that hackers may have accessed the personal data during a cyberattack in July.

The bank defended the delay, saying it notified law enforcement and has been working to identify the affected accounts.

Nappier said that answer was insufficient.

“At the end of the day, JPMorgan Chase has some work to do not only to assure the holders of its debit cards, but also to restore the state’s confidence in the company’s ability to remain worthy of our continued business,” Nappier said. “I have no tolerance for anything less than quality customer service, and I expect the management of JPMorgan Chase to direct their full attention to remediating this problem.”