Emergency services were called to a suspected explosion after passers-by spotted gas pouring from a factory.

Fire crews, police and the ambulance service were called shortly before 9am on Sunday amid fears about hazardous gas at the Eastern Attachments factory at the Gaymers Industrial Estate in Attleborough.

MORE: Explosion at factory causes large gas cloudBut the loud bang and gas cloud turned out to be a safety valve releasing, after the pressure in a nitrogen gas tank grew too strong.

Fire engines from Attleborough, Wymondham and Sprowston were at the scene, along with experts from Norfolk Fire and Rescue Service's Environmental Protection Unit and ambulances from the Hazardous Area Response Team.

Maurice Gaymer Road was closed while investigations were carried out.

Eastern Daily Press: Norfolk Fire and Rescue Service at the scene of a small explosion on the Gaymers Industrial Estate in Attleborough. Picture Bethany Wales.Norfolk Fire and Rescue Service at the scene of a small explosion on the Gaymers Industrial Estate in Attleborough. Picture Bethany Wales. (Image: Archant)

Daniel Leslie, company director at Eastern Attachments, said the valve releasing had prevented disaster.

He said: 'With the sun coming out and it being hot and cold the gases are expanding and contracting.

'When they expand, it vents so it doesn't cause an explosion. It's a safety mechanism.

'In other cases when canisters have exploded they've been blown 20 miles away. We probably wouldn't be stood here.'

He added when the valve released it would have made a loud whoosh and bang sound resembling an explosion.

Mr Leslie confirmed there was no staff in the building at the time and no injuries had been caused.

Attleborough residents reported seeing emergency services rushing to the scene.

Shane Jolly, who lives nearby, said: 'I heard loads of sirens early this morning and saw on Facebook there had been a major gas leak. After the two deaths at Banham poultry it feels like things are getting crazy round here.'

Fire crews re-opened the road around 11.30am.

Roger Mitchell, station manager for the southern district of Norfolk Fire and Rescue Service, said: 'There is no threat to the public, no issues with the general public. The owners are now taking control of the incident as the leak has been sealed. So at this time we are now leaving the scene.'

At Gaymers Meadow a youth football game was suspended while police attended the scene.

Derrick Bint, manager of the Attleborough under-16s team, said officers limited access to the park as a precautionary step in case they needed to access the incident via the field.