ST. LOUIS — Since our report in February, FOX 2 has received dozens of phone calls and emails from people on both sides of the river who say they hear a strange low-repeating noise. There’s still no definitive answer on what’s causing it, but we’ve discovered some new leads and closed the door on some other theories.

The low rumble sounds like a generator running in the distance. It’s now morning at the same home in the Castlereagh neighborhood of North St. Louis County.

Beyond the birds chirping, you can hear the same hum in the background. The viewer who shared this video with us lives less than three miles northwest of Micah Mayfield’s home on Old Jamestown Road.

“So low that it’s almost inaudible but super consistent. Usually in the evenings after eight, you’d hear a very low humming noise that would come in kind of a wave pattern,” said Mayfield.

“I remember asking my husband, ‘Babe do you hear that noise?’ And he was like, ‘What noise?’ I said, ‘Listen,'” said St. Louis County Councilwoman Shalonda Webb.

Webb said she can hear the hum from her north St. Louis County home. She’s still got the county looking into it and so are we.

Nearby you’ll find Ameren’s Portage Des Sioux site and a Spire STL Pipeline storage facility. Both utilities investigated and say it’s not them. Same for the Corps of Engineers and Lambert Airport. Central Stone Company Quarry told St. Louis County it’s not doing anything during the hours people report hearing the hum.

“Once we know what it is, we want to communicate so we can put minds at ease. If it’s something that needs to be addressed, that we get a plan and we address whatever the cause of it is,” said Webb.

“Since I’m not sure what it is, it’s hard to guess what they could do. But if there’s a way to maybe keep that noise back from the residential areas, that would be great,” added Mayfield.

Viewers have suggested we investigate everything from barge traffic to grain bins – an industrial gas company in Madison County, Illinois – and the Taos Hum. Google it. We appreciate the tips and ask you to keep them coming, and we keep trying to find the source of this nuisance noise.