Material overheating is thought to be the likely cause of a blaze at Mont Cuet.
The emergency services were called to the green waste section at the landfill site at Chouet yesterday evening.
The Guernsey Fire and Rescue Service were called to the outside fire at around 20:00.
By 23:00 the fire was out and the fire crews had left the scene.
A spokesperson for GFRS said the fire was down to a batch of processed garden waste material overheating.
“The incident did not affect the Household Green Waste Site, which is adjacent to the landfill site. Both facilities are open today as normal,” they added.
Garden waste material from households and commercial operators is processed at Mont Cuet, to produce soil conditioner.
Garden waste deposited at the site by commercial and domestic gardeners is shredded and left in piles, known as windrows, to naturally break down over a period of around three months.
A States’ spokesperson said heat is generated as this material decomposes, and to reduce the risk of fire the windrows are regularly turned to prevent a build-up of temperature.
The fire yesterday is believed to have occurred in a windrow that was due to be turned.
There was no damage to equipment at the landfill site, which is open as normal today.
Site staff attended to assist GFRS in dealing with the incident, and no injuries were reported.