The main street in Midleton, Co Cork, was cordoned off yesterday because of mounting concern about levels of fumes in the area.
Gardaí are unsure as to the definite cause of the fumes. However, it is suspected they may have originated from tanks at a petrol station in the street.
The tanks are due to be drained out over the next few days in an attempt to alleviate the problem.
Officials from the Health and Safety Authority were at the scene yesterday to try to determine the source of the fumes.
The closure of Main Street did not cause major disruption yesterday as many traders were closed for the October bank holiday.
However, Allied Irish Bank on Main Street is expected to remain closed until the matter is resolved.
Cork East Fine Gael TD, Mr David Stanton, said local people had expressed fears about the serious smell of petroleum in the Main Street area.
"The Health and Safety Authority and the gardaí are working hard to figure out what is going on. It is a suspected leak from the petrol tanks. However, this area is full of limestone caves so it could be anything.
"The biggest worry is there would be a build-up of fumes leading to an explosion but I think the situation is being very well handled by the HSA and the gardaí."
A Garda spokesman said the street was being cordoned off as a "precautionary measure".
Traffic restrictions were in place on Main Street for much of yesterday afternoon as officials tried to establish the source of the problem.