Arsonists could be to blame for fires at Calne Aggregates and the Viridor landfill site in Calne.
Firefighters from Calne and Chippenham were called to the first fire at Calne Aggregates, Abberd Lane, at 9.01pm on Wednesday.
They found flames coming from a single bay barn containing two skips full of waste and used two hose reel jets to extinguish the fire.
Several cylinders were found in the building, including a fire extinguisher and a butane cylinder. These were unaffected by the flames, but they were cooled down as a precaution.
While the crews were out at Calne Aggregates, emergency call handlers were alerted to a fire at the Viridor landfill site in Sand Pit Lane at 9.45pm.
Two water pumps from Marlborough and a water carrier from Royal Wootton Bassett were sent to the site where 1,000 tonnes of landfill waste was on fire.
They found plumes of smoke billowing from the site and were there tackling the fire until 5.17am, hours after firefighters left Calne Aggregates at 10.43pm.
A spokesperson for Wiltshire Fire and Rescue Service said: “Both fires are considered suspicious and have been referred to the police.
“With the Viridor fire we did liaise with the Environmental Agency and also Public Health England, because of the smoke, but the fire was extinguished before there was a real issue.”