A federal judge will decide in the coming weeks whether the Tennessee Valley Authority must control its coal-fired power plant emissions, which North Carolina officials claim are drifting across its border and harming the state’s economy and health.

The 12-day trial wrapped up in the lawsuit filed against TVA by North Carolina’s attorney general. U.S. District Court Judge Lacy Thornburg heard the case. His precedent-setting decision is expected some time after September 15.

North Carolina asked in its lawsuit that the TVA be required to cap sulfur dioxide and other pollutants that cross into the state from its coal-burning plants in Tennessee, Alabama and Georgia.

The lawsuit said the state’s economy and health have been affected. It was the first suit of its kind filed over the coal plant emissions by a state in the TVA region, which also includes Kentucky, Mississippi and Virginia as well as North Carolina.

Morgan Sommerville of the Appalachian Trail Conservancy testified that air pollution harmed the health and lung function of hikers in the region. Other experts testified during the trial that emissions generated by the TVA plants were linked to asthma, decreased lung function, and premature deaths in downwind states. State witnesses also testified that emissions damaged the economy by decreasing tourism.