A lorry collided with a barrier at Forton Services and spilled 300 litres of fuel.
Fire crews from Lancaster and a specialist appliance and crew from South Shore equipped to deal with a fuel spillage were sent to South Devorgilla Drive at 8.10am on April 28.
Traffic from the service area had driven through some of the spilt fuel and had contaminated the exit sliproad before the affected part of the service station could be cordoned off.
The Highways Agency assigned resources to clean up the road surface there.
Highways England tweeted at 12.03pm that - #M6 The diesel spill has been cleared on the n/b entry slip for at #FortonServices J32-J33 and all lanes have re-opened.