A former KeySpan Corp. spokesman who says he was fired in retaliation for bringing allegations of accounting errors and possible financial fraud involving millions of dollars to the attention of other executives at the company will proceed with a lawsuit in federal court.

Finding that a reasonable jury could conclude that KeySpan, the nation’s fifth largest natural gas distributor, terminated the employee, Robert J. Mahony, in violation of protections afforded to whistleblowers by the Sarbanes Oxley Act, Eastern District of New York Judge Sterling Johnson Jr. denied KeySpan’s request for summary judgment.