Several Lawrence residents reported Monday that their Commerce Bank debit cards had been compromised following a security breach over the weekend.

Carl Bradbury, director of consumer card product for Commerce Bank, said Tuesday that about 1,500 customers in various states were affected by a “merchant’s” security breach. So far, four Lawrence residents have reported to the Journal-World that their cards were compromised.

Bradbury said he could not share the merchant’s name, when the breach occurred or how many customers in Kansas were affected because of the “ongoing nature of the investigation.” Bradbury said the 1,500 number is a rough estimate and could increase as time goes on.

“Results slowly flow in over time,” Bradbury said.

Bradbury said security breaches in the banking industry are not rare. He noted about “60 to 80 breaches are going on” at any given time.

“All banks always deal with breaches, but the customers are always protected and not responsible for loss out of their account,” Bradbury said. “People don’t realize how prevalent this is.”

Bradbury said that those affected by the breach will be notified and affected cards will be replaced. Affected customers will not be responsible for the fraudulent purchases.

A team of Commerce Bank employees work to identify patterns of fraud. Bradbury said that in about 80 percent of cases, Commerce Bank will notify customers of possible fraud “before the customer even realizes it occurred.”

Representatives at other Lawrence banks, including Capital City Bank, First State Bank, Central Bank of the Midwest, Intrust Bank and Bank of America, said they had not heard of the data breach and did not have reason to think their clients had been affected.

Commerce Bank has 360 banking locations in Kansas, Missouri, Illinois, Oklahoma and Colorado. Commerce has six locations in Lawrence.