Officials say too much rain and an influx of debris from last year's flood are causing the stench drifting from Iowa City's landfill.
Neighbors have been dealing with the smelly problem for more than a year, and have filed complaints with the Iowa Department of Natural Resources.
Landfill workers say the problem is the result of too much moisture, which is causing the trash to decompose faster than it can be buried.
The 180-acre landfill is about a mile from the western edge of Iowa City.
Public Works Director Rick Fosse says the city has spent close to $400,000 on the problem, mainly on upgrading the landfill's gas collection system. He says staff will continue to work on solutions.