INVESTIGATIONS are under way after a river running between Burnley and Todmorden turned orange for more than two miles.
Iron deposits are believed to have left the River Calder rust-coloured from Cliviger to the outskirts of Todmorden town centre.
Environment Agency officers will be surveying the river today, in an effort to isolate the source of the pollution outbreak.
An agency spokesman said: “There are a number of old mine workings which discharged into the River Calder, or its tributaries, so we will be looking for where something has gone wrong.”
Problems have previously been blamed on iron deposits from former mine workings near Cloughfoot, between Bacup and Todmorden, which has affected Midgelden Brook, which runs into the Calder.
But John Delaney, the Coal Authority’s corporate manager, has confirmed that the £3million water treatment works, opened last year to deal with the issue, is operating without any difficulties.
John Millar, 43, of Burnley Road, said: “It’s about time they found a way of getting this problem once and for all.
“You’ve got to wonder about what effect it’s having on the wildlife around the river because it takes ages for it to clear up.”
Work also begun yesterday on a major operation by Environment Agency contractors to address flooding problems in Water Street in Todmorden.
Three properties are being demolished and reconstructed and protection works are being carried out underneath the Royal George pub.