One in three U.S. workers has had a workplace romance, according to a Society for Human Resource Management study, a finding that underscores why legal observers say Norfolk Southern Corp. surely will not be the last major company tripped up by an inappropriate relationship involving the C-suite.

The Atlanta-based rail giant on Sept. 11 fired CEO Alan Shaw and one of his direct reports, Chief Legal Officer Nabanita Nag, saying that the preliminary results of an inquiry conducted by outside counsel found the pair were involved in a consensual relationship that violated the company’s policies and its code of ethics.