Around 3,500 homes remain without their gas supply as engineers continue to repair a major leak.
Properties in Fishcross, Dollar and Tillicoultry in Clackmannanshire have been cut off and Fishcross and Clackmannan primary schools were closed as a precaution.
The leak started at about midday on Tuesday when a farmer in Fishcross ruptured a large pipe while doing drainage work in a field, Scotland Gas Networks (SGN) said.
Engineers have secured the leak and are now working to repair the damaged pipe. SGN said it had to visit all affected properties in the area to ensure gas supplies were turned off before services can be restored.
Roads in the area have been closed but police said homes have not been evacuated and the gas level in the air is being monitored.
The supplier said portable electric heaters and cookers have been distributed to some elderly and vulnerable people in the area and more are available at an incident centre set up in Tillicoultry Community Centre.
A spokeswoman for SGN said it hopes to start restoring supply to some homes by the end of Wednesday, but it could take until the end of the week to reconnect every property.
"Engineers from Scotland Gas Networks will be calling at each affected property to ensure that all gas systems have been shut down before beginning to restore supplies," she said. "Unfortunately it is too early to say when supplies will be restored but this is likely to take a few days.
"If you are elderly, disabled, chronically sick, have young children or other special needs, we have portable electric appliances available for cooking and heating. These can be obtained by calling our 24-hour customer service centre on 0845 070 1432 or contacting our staff on site.
"We sincerely regret the inconvenience this may have caused and would like to reassure customers that we are working hard to resolve this situation as quickly as possible."