Federal bank regulators are suing more than a dozen former officers and directors of a failed Macon bank claiming they were grossly negligent in their oversight of the institution.

The lawsuit against insiders of Security Bank of Bibb County is the latest in a string of civil liability lawsuits that have followed in the wake of bank collapses. Georgia has led the nation in failed banks since mid-2008.

The Bibb bank was a subsidiary of Macon-based Security Bank Corp. Six Security Bank Corp. subsidiaries, including three in metro Atlanta, were seized by regulators and sold to State Bank & Trust in July 2009.

The Federal Deposit Insurance Corp. is seeking $21.8 million related to 10 different loans or credit lines that the regulator said “were improperly approved by (the) defendants,” according to a lawsuit filed last month in U.S. District Court in Macon.

The suit names 15 former officers and directors, as well as the estate of one former board member who died in 2010. Among those named as defendants are former bank presidents Richard A. Collinsworth, Daniel Forrester and Melville A. Jamison III; and Richard W. White Jr., the bank’s former chairman.

“Our clients strongly deny the FDIC’s allegations and intend to vigorously defend against them,” said Walt Davis, an attorney representing most of the defendants. “In addition, the FDIC has brought similar claims that have been previously rejected by the courts across the country.”

The FDIC said the defendants gave “improper approval” of loans to some borrowers, including Security Bank Corp. insiders, with “preferential terms or with preferential administration.” The suit also contends the defendants approved loans that violated bank policies.