Drivers stopped at the gas stations Thursday to fill up in case Isaac knocks out the electricity, which would also stop the flow at the pump.
As of 2 p.m. Wednesday, South Florida remained in the cone of probability as Tropical Storm Isaac continued moving westward.
"There is lines at the gas station and the power is out," said Scott Nadelman.
If Isaac hits South Florida, stations will be prepared after a new law was passed to help keep the pumps working. Gas companies across South Florida are required to have a backup power source and outlets installed for a generator. The law was passed in response to Hurricane Wilma, which left widespread outages, causing hundreds of gas stations to close.
"You can't imagine how backed up the expressways were and people tried to get to gas stations," said Brenda Spiwak.
"I'm taking this real serious," said Jim Shouse.
Shouse said he made three trips to fill up on Wednesday.
"We're looking at 42 gallons to be exact with the generator," said Shouse.
"You can never be too prepared. If I don't use the gas, I just throw it in the car so it's not one dollar out of my pocket," said Nadelman.