Cleaning up the Chicago River may please some recreationists and environmentalists, but it could also contribute to global warming, according to a recent story in the Chicago Tribune.

Though the Windy City is often citd as one of the greenest cities in the nation, it is also the only major city in the U.S. that doesn’t disinfect its sewage. Environmental groups have offered many reasons why the sewage should be disinfected before it reaches the river, but doing so could increase carbon emissions, according to a report by engineers at the Metropolitan Water Reclamation District of Greater Chicago, the group responsible for protecting the Windy City’s water.

The district found that disinfecting the bacteria-laden wastewater would require more electricity, which would produce more emissions and contribute to global warming. According to the district, its carbon footprint would increase by more than 98,000 tons a year if the water were disinfected. In addition, district officials told the Tribune that there is no evidence the water poses a threat to public safety.

"With additional treatment, you have to weigh how much water quality is actually being accomplished with more harm to the environment in another way," Louis Kollias, the director of the district's Monitoring and Research Department, told the Tribune.

Meanwhile, those in favor of disinfecting the water continue to voice their opinions. Currently, Illinois Gov. Pat Quinn and Chicago Mayor Richard M. Daley have joined environmental groups like Friends of the Chicago River in pushing for the district to disinfect the water. Critics say the district has used every excuse in the book to avoid the task.

Rob Sulski, an Illinois EPA water pollution programs manager, told the Tribune, "You look at the record here and every potential and possible argument against doing anything has been put into testimony.”