Environment Agency officials say they will investigate after receiving reports that parts of the River Colne and Huddersfield Broad Canal have turned orange.
Annette Monroe, 57, who has lived in Leeds Road, Deighton, for over 10 years said she noticed their changing colour yesterday when she looked out of the window.
Both waterways near Syngenta ran orange and Ms Monroe said: “The canal feeds into the pond at the back of my house. Fortunately the pond hasn’t turned orange. I’d just like to know what has happened.”
An agency spokeswoman said officers would investigate once Ms Monroe submitted a formal report.
Rivers and canals in Huddersfield turning orange is nothing new.
In February the Examiner reported that both the River Holme in New Mill and Brockholes had run bright orange, as well as a canal in Marsden.
Scientists said in that instance the colouration came from minerals in old mine workings and was harmless to health.
After the River Holme ran orange, Huddersfield University scientist Dr Jeremy Hopwood explained that the colouring was known as ‘acid mine drainage’ and there was no health risk.