A clogged sewer connection behind Whole Foods Market led to a rather fragrant backup during the Monday morning rush hour last week.

Forest Park resident Carl Nyberg said that he had smelled sewage when he passed under the viaduct Sunday night. When he walked back that way again Monday morning, he said the scent was far stronger and standing gray sewage water in the high gutter along the west side of Harlem Avenue under the Green Line viaduct.

“It was pretty oppressive by Monday morning,” Nyberg said. Even worse than the smell, the pool of sewage was being splattered halfway across the sidewalk by the underpass leading to the Forest Park Green Line terminal. Nyberg is a contributor and columnist for the Forest Park Review.

“It was basically sitting right in front of the Forest Park [el] entrance,” said Nyberg. “There was this gray, nasty looking stuff being splashed up by passing cars.” Those cars’ tires tracked the mess as far as the Dunkin’ Donuts a quarter-block south of the overpass.

River Forest dispatched a public works crew to the River Forest Town Center around 9 a.m. to locate the blockage, which they found in a trap behind the Whole Foods Market.

“Our crew used a root cutter and found the remnants of a towel or cloth in the trap,” said Greg Kramer, River Forest public works director. “There was an accumulation of grease behind that.”

Kramer said it took about three hours to clear up the jam. According to River Forest and Forest Park officials, the sewage backup was the first of its kind at that location. Both Kramer and Forest Park Village Administrator Michael Sturino said that the problem appeared to have been caused by a combination of grease from the Whole Foods and the towel, which acted as a dam to other material in the sewer pipe.

Sturino said in a letter dated Feb. 16 that he had spoken with Whole Foods officials who indicated they would take steps to assure that there is no repeat occurrence.

“Whole Foods has assured me that that they are going to renew their commitment to more regular maintenance of their own lines so that it does not act as a contributor to this type of situation in the future,” the letter reads in part.