Llangefni: Vion food factory ammonia gas leak inquiry
Officials are investigating after ammonia gas leaked at a food factory on Anglesey.
Ten fire service vehicles were dispatched when up to two tonnes of gas leaked from the Vion food processing plant on Llangefni Industrial Estate.
Residents were advised to stay indoors during the leak at 21:09 BST on Monday.
It is believed there is no longer a threat to local air quality, but anyone with health concerns is advised to contact their GP or NHS Direct.
The police and ambulance service attended, as well as seven fire appliances and three specialist vehicles by North Wales Fire and Rescue Service.
A fire service spokeswoman said: "Firefighters with protective clothing and breathing apparatus isolated and stemmed the leak to disperse the vapour cloud with water, and to contain the affected area within the site.
"Local residents were advised to stay indoors and to close doors and windows."
Environment Agency Wales said between one and two tonnes of ammonia gas were believed to have leaked.
It said some of the gas - which is used in the site's cooling systems - may have turned into liquid as the fire service used water to prevent it dispersing.
Officers are checking the river Cefni, but EAW said "early indications suggest that no serious damage has happened".
The agency regulates the plant, which must operate within the terms of a permit.
David Edwell, north Wales area manager for EAW, said: "Our officers worked closely with the fire and rescue service until the early hours of the morning on this incident.
"Our incident room was closed at around 3.30 in the morning, but we're back on site now to investigate what happened and why."