LANSING — About 8,500 people who received unemployment benefits in Michigan may have had their personal information exposed.

JPMorgan Chase notified the state Unemployment Insurance Agency that an unauthorized party may have viewed personal information of people who use the Chase debit card for unemployment benefits.

Chase estimates the security compromise may have affected about 465,000 cardholders nationwide, including 8,500 in Michigan who accessed the bank website between mid-July and mid-September. Social security numbers, bank account numbers, passwords, home and e-mail addresses and phone numbers could have been exposed.

The New York-based bank discovered the breach on Sept. 17. It fixed the issue and notified law enforcement. But it didn't tell the UIA about the issue until Dec. 3. The state said it will begin notifying affected customers via email on Thursday, nine days after it found out about the problem. Chase also will email cardholders.

“We have worked closely with JP Morgan Chase to share our concern about the delayed notification and to ensure that the state receives immediate notice of future problems,” Michigan's Chief Security Officer Dan Lohrmann said in a statement. “We work around the clock to keep citizen information and data protected, and I feel confident that everyone involved in this event understands the importance of protecting personal information.”

Chase's first priority upon discovering the issue was to protect its systems, cardholder data and accounts, said spokesman Michael Fusco.

"We quickly fixed the issue and started an investigation to figure out what happened, what, if any information was exposed, and who was affected," he said. "We reviewed the results of the investigation and quickly took steps to communicate with everyone impacted."

The company has been monitoring the issue and hasn't found any evidence that the data was used improperly, Fusco said. The breach did not impact other Chase debit or credit card holders.

UIA Director Shaun Thomas said in a statement that he's deeply concerned about the incident and encourages customers to take advantage of free credit monitoring services provided by Chase.

When asked why UIA waited more than a week to notify the customers, spokeswoman Lynda Robinson said the agency was working with Chase to identify the potentially impacted customers and negotiated the length of time that Chase would provide identity protection.

Customers can call Chase at 1-866-849-5255 to learn more about the incident. Affected cardholders who receive a redemption code from Chase can enroll in two years of free credit monitoring online or by calling 1-866-746-4253.

Email Melissa Anders at manders@mlive.com. Follow her on Google+ and Twitter: @MelissaDAnders. Download the MLive app for iPhone and Android.