Overview: - A DTE Energy lawyer argues the EPA has failed to prove the utility is an operator of its Zug Island subsidiary EES Coke Battery. - A U.S. attorney says EES Coke Battery "violated the permit" issued by Michigan's environmental regulator. A DTE Energy lawyer asked a federal judge Monday to decide whether the utility is liable for the Clean Air Act violations of its Zug Island subsidiary EES Coke Battery. The motion comes in a bench trial that began Sept. 15 in the EPA’s Clean Air Act lawsuit against EES Coke Battery. DTE Energy was added to the lawsuit as a defendant last year.