Emergency services are tackling a fire after what is thought to have been an explosion at a chemical factory.
North Wales Fire and Rescue Service said it was called to a fire in the production area of the Synthite factory on Denbigh Road, Mold, Flintshire, at about 14:05 BST.
About 20 workers and contractors were evacuated to a police cordon in the town.
It is believed one man was injured and has been taken to hospital.
One woman said she rushed to pick up her partner who works close to the factory.
Emily Jones said the building where her partner works was "quickly evacuated as well as many others surrounding".
"[I've] never driven so fast in my life to pick him up from work, all safe and hopefully all others in area will be as well," she said.
North Wales Police said the A541 has been closed from the junction at Dreflan to Black Brook Road Rhyd y Goleu.
Synthite has been on the site since the 1950s producing chemicals, including formaldehyde and chemicals used in agriculture.