HAMPTON, Ga. -- Water found in the fuel tanks of cars driven by Denny Hamlin and Dave Blaney during Sunday's NASCAR Nextel Cup race at Atlanta Motor Speedway was not isolated to those teams, a NASCAR official said Monday.
Water also was discovered in the fuel of the Penske Racing cars driven by Kurt Busch and Ryan Newman after returning to Charlotte, N.C. In addition, water was found in the fuel cell of all three Richard Childress racing team cars belonging to Kevin Harvick, Clint Bowyer and Jeff Burton.
Greg Biffle believes his car may have had water in its fuel, although no evidence was found.
NASCAR Nextel Cup Series director John Darby said the problem is more widespread than originally thought and that NASCAR has issued bulletins to all Cup and Truck Series teams to check for evidence of contamination so they can locate the source.
"There are multiple teams that are showing positive for some level of water contamination level in their fuel," Darby said, according to the Associated Press. "I can't tell you the exact number. It's more than two and less than 43 at the moment."
Darby said the contamination could have occurred as early as Thursday when the trucks took the track for the first time. He said NASCAR is working with Sunoco to aggressively find out how the water got there.
"It's really difficult to pinpoint," he said. "We have to almost work backwards."
Darby said everything from the underground fuel-holding tank at the track to the fuel trucks that deliver the gas to the individual gas cans are being analyzed. He said the underground tank is the least likely source because there is an alarm system located that can detect the slightest amount of contamination.
"All reports from that show zero water," he said.
Darby dismissed sabotage as a possible explanation, saying too many teams were affected for anyone to have been singled out.
"For those who have their evil, twisted conspiracy hats on, we want to put that to rest,'' Darby said, according to the AP. "If it was sabotage, it would have to be the kind of thing where someone hates NASCAR racing across the board."
Darby doesn't believe water was the reason Hamlin's car shut down on the restart with three laps remaining Sunday, allowing Jimmie Johnson to take the lead and win to pull within nine points of teammate Jeff Gordon in the championship standings.
He believes Hamlin's car sputtered from being low on fuel just as Gordon's did on a late restart earlier this season at Talladega.
Mike Ford, Hamlin's crew chief, disagreed. He said there was plenty of fuel remaining to fire the engine and that the water simply shut the engine down.
"You saw several guys stumble on restarts," Ford said. "You're like, 'This could be a problem.'"
Ford first noticed water in Hamlin's car during the first pit stop.
"We found water in our catch can," he said. "The first restart after that the car stumbled for a couple of laps. It stumbled after the first couple of stops, actually.
David Newton covers NASCAR for ESPN.com. He can be reached at firstname.lastname@example.org. Information from The Associated Press is included in this report.