DENVER — Runners had some sore legs Monday, one day after Denver’s popular Rock ‘N’ Roll Marathon. But it’s not just race times and winners on top of mind. A lot of people were talking about a stinky smell on the race route along the South Platte River.

“It smelled like sewage,” runner Lisa Goldberg said. “It wasn’t that strong at first and I thought it was the runner ahead of me. I ran past him and I looked behind me and I shot him a dirty look.”

But it wasn’t fumes from a fellow runner. Goldberg said the stink stayed the course throughout an industrial area.

“And at mile 18, when you’re running a marathon, that’s when you start getting really tired and your stomach starts bothering you,” Golderg said. “And it kind of made me nauseous.”

Upset runners also took to social media.

“The course was boring, smelly, mostly concrete and desolate,” one wrote.

You can’t miss the likely source, with wastewater treatment facilities lining the trail.

But Goldberg isn’t blaming race organizers, who were forced to find a new route, citing upset neighbors and drivers who were trapped by the road blocks of the old course through downtown Denver.

“I think they were in a really difficult situation and they were just trying to find a good place,” Goldberg said.

That proved to be a difficult task. With no other options, organizers canceled the full marathon next year.

Metro Wastewater Reclamation District said it did not receive any formal complaints over the weekend. But it does have facilities in place to manage and monitor odors. A spokeswoman said it currently meets all air quality standards.