The Environment Agency has launched an investigation into pollution in a stream in West Yorkshire.
Hole Bottom Beck is one of several watercourses that come together to form Bradford Beck. It flows northwards from Queensbury passing a disused railway tunnel which is the focus of a engineering work by AMCO-Giffen.
Part of the work involves pumping floodwater from the tunnel into a culvert which Hole Bottom Beck flows through.
Queensbury Tunnel campaigners – who want to reopen the tunnel as a cycle path connecting Bradford to Halifax – said that locals reported last week seeing pollution in the beck, extending for at least 200 metres from the exit of the culvert close to Brow Lane in Clayton.
Diane Fogarty, who owns land nearby, said: “The pollution is a disgrace. We’ve had to stop our dogs drinking from the beck; it’s affected a lot of vegetation on the banks and the smell is awful. It’s got into our lake which we’ve spent a lot of time, effort and money on over the years, creating a valuable wildlife habitat; there are hundreds of fish in there now.”
The Environment Agency confirmed an inquiry is underway after receiving calls on Friday.
A spokesman said: “Our officers saw a small amount of oil on the surface of the water. We spoke to the contractor and will be returning this week to monitor the situation and check it is not an ongoing issue.”
Highways England’s Historical Railways Estate manages the tunnel on behalf of owners, the Department for Transport.
A spokesperson for Highways England said: “We are aware that diesel has recently been found in a nearby beck.
"Our contractors have provided the Environment Agency with details of our work to assist their ongoing enquires.
"Pumping was not taking place from within the tunnel on the dates the diesel was discovered.
"Regular checks of the outflow point into the beck have not identifed the presence of any diesel whilst the pumps have been in operation.
"If any diesel had been identified our contractors would have stopped pumping immediately and deployed the correct protective apparatus which they hold on site.”