A noxious odour which hit parts of a coastal town on Friday night could return, residents have been warned.
Residents in Seaford, East Sussex, were told to stay indoors and keep windows closed after complaining of stinging eyes and feeling sick.
East Sussex Fire and Rescue Service could not find the cause of the smell, but warned pockets of the odour could return as the weather warms up later.
Sussex Police said the stench resembled “burning plastic”.
The smell was first noticed in The Ridings area of the town at about 18:00 BST and did not fade away until about 23:00.
George O’Reilly, a hazardous materials officer, said: “People will be waking up this morning without the smell and able to go out and open their windows.
“If the source of this smell was something sprayed on the ground for agricultural reasons, it could be as the weather warms up, people will get a whiff of it again.
“Anybody who smells it again or has any concerns should contact the fire service immediately.”
He said emergency services, including a fire engine and technical rescue unit, quickly discovered there was no risk to public health but despite a thorough search of the area the source could not be found.
A spokesman for Lewes District Council said: “Air quality and pollution officers will be making further investigations in the coming days.”
Image caption Seaford Head is a popular spot to enjoy the view of the Seven Sisters cliffs
In August, about 150 people were treated for breathing problems, stinging eyes and vomiting after a toxic “mist” engulfed part of the East Sussex coast.
Visitors to Birling Gap and other beaches were evacuated when a mystery gas was blown ashore from the English Channel.
It is believed the most likely source of the fumes was a ship illegally flushing its tanks with chemicals.
Mr O’Reilly said the smell in Seaford was not linked to the August incident as it was not a “cloud” from the sea.