Smoke from a fire involving 200 tonnes of waste in Rushton can still be seen almost 36 hours after the blaze broke out.
Fire crews remain at the Mick George waste site in Oakley Road after the incident at about 10.30pm on Tuesday (July 23).
A change in wind direction into today (Thursday) has meant Northamptonshire Fire and Rescue Service has been receiving calls from concerned residents in Desborough, about four miles west, who can smell the fire or are seeing smoke from it.
A fire spokesman said: "People affected by either a smell of burning or smoke from a waste fire in Rushton are being advised to keep doors and windows closed."
Firefighters continue to support on-site operations to ensure the deep-seated fire is extinguished, with a progress review due tonight.
A Mick George spokesman said: "The cause of the fire has not yet been identified, however it is most likely a consequence of the current record-breaking heatwave being experienced across the country."