Airports supplied by an oil depot near Hemel Hempstead hit by explosions insist there will be no shortages of aviation fuel for aircraft.
Some flights have been cancelled at Heathrow
Luton Airport, where flights are continuing as normal despite it being just 10 miles away from the blast, said it had sufficient alternative supplies.
Heathrow, which is directly supplied by a pipeline from the Buncefield site, also said it had other fuel sources.
But the airport said some flights had been cancelled because of the smoke.
"We have fuel supplies at Heathrow and we also get aviation fuel from a facility at Fawley near Southampton," said a Heathrow spokeswoman.
"The depot near Hemel is one of our supply depots but there is no indication that there will be a shortage in the foreseeable future."
A Luton spokeswoman said: "Flights are taking off and landing as normal."
"We do get fuel from the Hemel site but we do get supplies from a number of other facilities," she said.
"The main problem for us today is the closure of part of the M1 near the airport.
"There are diversions and we are advising passengers to leave a lot of extra time to get to the airport."