Fire at River Lane Industrial Estate, Saltney
Firefighters remain at a blaze on an industrial park in Flintshire, more than eight hours after it started.
Crews were called to burning recycling waste on River Lane Industrial Estate, Saltney, at 08:08 BST on Tuesday.
At its height, 25 firefighters were tackling the blaze, and crews remained at the scene all day, although the fire is believed to be contained.
Pollution from the blaze has had a "minimal impact" on the River Dee, Natural Resources Wales believes.
Two appliances from Deeside, one from Flint and two from Cheshire attended.
They were joined by an aerial ladder platform from Wrexham fire station, a high volume pump from Llandudno and the incident command unit from Rhyl.
Dave Powel, of Natural Resources Wales, said: "Our officers are on site to assist the North Wales Fire and Rescue Service and assess the potential impact of this incident on the environment.
"Our biggest concern in incidents such as this is dealing with the water that's used to fight the blaze.
"It picks up a lot of pollutants from the burning material and can cause a lot of damage if it gets into streams and rivers.
"At present the pollution appears to be contained and there is minimal impact on the River Dee and surrounding area."
Public Health Wales advises residents to stay indoors and close doors and windows if smoke is visible at ground level.
Nobody is believed to have been injured.