Officials say fire departments in Lake and McHenry counties have been receiving dozens of 911 calls for a natural gas odor Tuesday that is believed to be originating from Iowa.
The 911 calls began in McHenry County just before 4 p.m. Tuesday from residents smelling a natural gas odor.
The reports came in from throughout McHenry County, including Woodstock, Marengo, Crystal Lake, McHenry, Lakewood, Cary, Huntley and Union.
Marengo Fire and Rescue Districts Communication Specialist Alex Vucha said Marengo was the first to begin receiving the complaints and firefighters were unable to locate any leak or source of the odor.
Nicor Gas does not believe the airborne odor calls are related to their pipeline system.
By 4:45 p.m., residents in Lake County began calling 911 to report strong gas odors outside as the odor moved with the wind from west to east.
The reports came in from the majority of towns in Lake County, including Fox Lake, Wauconda, Round Lake, Mundelein, Round Lake Beach, Volo, Lake Villa, Grayslake, Lindenhurst, Gurnee, Vernon Hills, Zion, North Chicago and Waukegan.
Fire departments in Lake County were also unable to locate any leaks.
Authorities believe the odor originated from Iowa and quickly traveled across northern Illinois and into the Chicago suburbs due to the wind and temperatures, Vucha said.
Residents who smell the odor do not need to call 911 unless they smell it inside their home or are exhibiting symptoms.
The Clinton County, Iowa Sheriff’s Office said they responded Tuesday morning to several reports of a natural gas-like smell in and around Highway 61 and DeWitt.
An investigation showed the odor likely originated during the maintenance of equipment in Cedar County, Iowa, the sheriff’s office said.
Sheriff’s officials did not say what kind of maintenance was being performed but said there was no threat to the public.
The McHenry County Emergency Management Agency said the odor traveling from Iowa is not actually natural gas but rather a chemical inserted into natural gas to create its smell.
“Weather conditions are keeping this near surface altitudes and not dispersing it quickly,” the agency said.