A forensic investigation will be carried out into reports that the River Tawd in Skelmersdale is polluted.
Some residents have raised concerns after contacting West Lancashire MP Rosie Cooper to say fish and wildlife were being killed.
MP Cooper has now secured an Environment Agency forensic investigation.
Residents claim this isn’t the first time the water has been polluted, and this latest occasion there is a strong smell of fabric conditioner.
Rosie Cooper MP challenged the Environment Agency to use whatever scientific means are available to them to identify the culprit and hold them to account, with many believing a local business is to blame.
She said: “It is unacceptable to see our rivers and wildlife polluted in this manner and seemingly this isn’t the first time this has happened in the River Tawd.
“I contacted the Environment Agency calling for an urgent investigation and for samples to be taken from the river to identify the contaminants so we can find out just who is responsible.
“I’m pleased that the EA are taking this matter seriously and have assured me that they will be using an external forensic scientist to analyse samples they have collected.
“Further, the EA have now committed additional funding for culverting work which will help them in narrowing down potential sources.
“For Skelmersdale residents and I it is extremely disappointing that we have to undertake these investigations – no person or business should be damaging our natural beauty spots like this, and should the culprit be found they will be dealt with by the authorities.”