OWNERS of Fawley refinery have revealed the cause of a huge bang that shook a large number of homes in the area last night.

The petro-chemical company ExxonMobil says the incident involved a "sudden release from a utilities air line" on a unit that had been shut down for maintenance.

People living near the huge refinery say they heard sirens and saw plumes of smoke shortly after 8.40pm.

The complex has its own firefighting team but crews at nearby Hardley fire station were put on alert.

Posting on social media they said: "Currently on standby at the station following sounds of an explosion near Fawley.

"We are remaining on the station as a precaution at this time, ensuring we are out the door as quickly as possible if needed."

In a statement, ExxonMobil said: "The cause of the noise earlier this evening was a sudden release from a utilities air line on a unit already shut down for maintenance.

"There was no risk to communities, there have been no injuries and operations are continuing as normal."

Many people took to social media after hearing the bang, which caused homes to shake and windows to rattle.

One woman said: "I live in Holbury, very close to the refinery, and heard a massive boom. It shook the house and at first I thought there had been a gas explosion in a neighbouring property.

"My husband and I could see plumes of smoke coming from the refinery and heard the sirens sounding."

Another added: "I think it's about time our local council called senior Exxon managers to a public meeting to answer our concerns instead of sending us soothing text messages."

A Rollestone Road resident said she thought her roof had collapsed.

Other posts said the bang was heard as far afield as Cadnam, Calmore and Romsey.

Last night a police spokesperson said: "We have received reports of a loud bang at Fawley refinery.

"This was also heard by officers from the Waterside Police team and officers from Response and Patrol who were in the Waterside area.

"Police immediately responded to the scene.

"The refinery has stated that at this time there is no concern to the public and the incident is being investigated.

"Refinery employees will be searching the site to confirm and identify any issues but everything is stable and no issue has been identified by sensors or CCTV.

"Fire crews are on standby and the Waterside team will be patrolling the area."