Fairfield fire officials say they worked with Southern Connecticut Gas to investigate. They say they determined there were no underground gas leaks, stressing the public is safe.
However, fire officials say they were unable to pinpoint the source of the odor.
They say the smell might have come from a truck, either carrying mercaptan or propane, that may have been leaking as it traveled through the impacted neighborhoods.
Fire officials say the 911 dispatch center received 50 to 100 calls about the smell Wednesday night.