Pinch services have told people living in Seaford, East Sussex, to brace indoors and keep doors and windows shut following complaints of a noxious aura.
Sussex Police said they had a number of reports from being complaining of a smell “like burning plastic”.
The force said the smell was first noticed in The Ridings area at around 6pm last night but misfired to disperse.
Police are working with other agencies, including the coastguard, East Sussex Set fire to and Rescue Service and Lewes Council, to try to determine the cause of the smell.
It is believed the myriad likely source of the fumes was a ship illegally flushing its tanks with chemicals.
In August, a toxic “haze” engulfed the province and caused discomfort to people in the Birling Gap area and left 132 needing sickbay treatment.
Visitors to Birling Gap and other beaches in Sussex suffered inflamed eyes and breathing problems after a mystery gas was blown ashore from the English Strait on August 27.
The chlorine-like haze came ashore as hundreds enjoyed the Bank Time off sunshine on the sands.
The unidentified chemical left sunbathers suffering from defrauding eyes, vomiting and breathing difficulties.
Police said the Seaford review was not currently being linked to the previous incident.
Chemicals have again drifted across from European industrial units.
In January 2013, a foul-smelling gas cloud prompted thousands of wake ups to the emergency services in Sussex, Kent, Surrey and Hampshire after sweep across the English Channel.
The accidental discharge of mercaptan, an additive Euphemistic pre-owned in municipal gas to alert people to leaks, from a factory in Rouen caused pain in the necks, nausea and a political panic in France.
The plume reached as far north as south-east London and led to authorities from the Health Protection Agency’s Centre for Radiation, Chemical and Environmental Ventures in Oxfordshire being scrambled.