Anglers in West Yorkshire have said hundreds of fish have died after chemicals leaked into the River Colne following a fire at a factory.
More than 150 firefighters tackled the blaze at Grosvenor Chemicals in Linthwaite on 24 May.
The factory manufactured herbicides, pesticides and glue-based products.
Despite concerns about the foam used to fight the fire, initial Environment Agency tests showed herbicides to be the main pollutant in the river.
Ray Collier, from the Slaithwaite Angling Club, said: "It's sickening when you see the quality of the fish as well as the numbers.
"Even the small fish, you know that they've probably been born in this river, it's taken a long time to get to this stage where they're reproducing in the river, and now they've just, in 24 hours, been wiped out."
Fish stocks in the Colne were only just recovering from an earlier chemical leak at Slaithwaite in March 2008.