Schoolchildren kept indoors as a precaution.
A petrochemical plant in Grangemouth has been partially evacuated after a gas leak.
The leak was discovered in a pipeline on a gas manufacturing area at the Ineos site in central Scotland at midday on Tuesday.
Emergency services were called to the scene and the south side of the site has been evacuated and roads have been closed.
The Scottish Fire and Rescue Service sent eight vehicles to the scene to support the energy giant’s on-site fire engines.
The ambulance service sent a special operations response team but it is understood no casualties are expected.
Ineos said in a statement: “At noon we detected a leak on a pipeline inside our KG (Kinneil Gas) manufacturing plant at Ineos Grangemouth.
“Emergency services are in attendance and we requested that Police Scotland close the Wholeflats Road as a precautionary measure.
“The incident management team have been mobilised to manage the situation.
“Purely as a precaution and to allow our response team to manage the situation, we have closed a number of access gates and are allowing only essential personnel to enter the south side of the site.
“All non-essential Ineos personnel who would normally be working in this area have been requested to report to their line manager.”
Falkirk police said in a statement: “Emergency services are currently at the scene of an incident at Grangemouth which happened at around 12.15pm today.
“All emergency services, local authority and partners are in attendance.
“A number of access roads in Grangemouth area are closed and drivers are asked to avoid the area and find alternative routes.”
Pupils at primary and secondary schools in Grangemouth were kept indoors over lunchtime as a precaution on request from the police, a Falkirk Council spokesman said.
He said there were currently no plans to prevent the children from going home at the usual time.