A review is under way into how emergency services responded to a chemical cloud in East Sussex that left scores of people needing treatment.
Parts of the coastline were evacuated during a busy bank holiday weekend after a noxious haze reached the shore from Eastbourne to Birling Gap, near Beachy Head.
Around 150 people needed treatment for stinging eyes, sore throats and vomiting after the incident in August.
Sussex Police said those who were affected experienced "mostly minor" effects from the gas.
A review has been launched into "all aspects" of the emergency service response to the incident, the Department for Environment, Food and Rural Affairs (Defra) has confirmed.
A spokesman said: "The review is at an early stage but it is to explore the operational response should a similar event happen again."
An investigation into the source of the emissions has been unable to identify where the gas came from.
It comes after reports of a similar incident in October when residents in Seaford complained of a noxious odour which caused stinging eyes and nausea.