Emergency services have attended a chemical incident on Llangefni Industrial Estate onAnglesey.

North Wales Fire and Rescue Service mobilised seven fire appliances (from Llangefni, Bangor, Holyhead, Menai Bridge and Rhosneigr) as well as three specialist appliances (including an Environmental Protection Unit from Rhyl) to the incident at 21.09hrs this evening (Monday 13^th August). Staff from North Wales Police and Welsh Ambulance Service NHS Trust were also at the scene.

An unknown quantity of ammonia gas had escaped from a food industry related premises on the industrial estate.

Firefighters worked in protective clothing and breathing apparatus to isolate and stem 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 keep windows and doors closed until further notice.

All 20 personnel at the premises were evacuated safely.

It is standard practice at such incidents to ensure arrangements are in place for anyone with related symptoms (eg streaming eyes) to be treated and decontaminated at the scene or transported to hospital if necessary.

Four local residents displaying such symptoms - two adults and two children - were treated by paramedics at the scene. They attended hospital for precautionary checks and were later discharged.

Emergency services are expected to remain at the scene whilst further assessments are carried out.