A MAJOR investigation has been launched after the River Irwell, running through Bacup and surrounding areas, began to run orange.

Scientists from the Environment Agency have launched a probe on the waterway after heavy rainfalls are thought to have caused old underground mineworks to collapse and a water treatment plant has been swamped.

Resulting iron oxide deposits have caused the Irwell's water to turn orange along an 18 to 20 mile stretch, running south from Bacup.

An Environment Agency spokesman said: "At approximately 7.30am this morning we received a number of calls from members of the public, reporting an orange substance in the river.

"An environment officer responded to the reports immediately to investigate the source of the pollution.

"It is believed that very heavy rainfall over the course of the weekend, combined with a suspected underground collapse at an abandoned mine near Old Meadows, Bacup, has caused more water to flow from the underground workings at the mine, overwhelming the nearby water treatment plant.

"As a result large quantities of untreated water are discharging into the River Irwell, giving the river an orange appearance which is suspected to be iron oxide (ochre).

"The impact of the pollution on the river and its wildlife is currently being assessed.

"Water samples and photographs of the pollution are being taken.

"There have been no reports of any fish deaths or other damage to wildlife, but an ecological survey is to be carried out in due course."