Action taken as mystery grey sludge suspected of killing plants invades towpath near Leeds Dock

A mystery paint-like substance has invaded a riverside footpath between Leeds Dock and Thwaite Watermill on several occasions since the end of last year. The picturesque path is popular with runners and cyclists and forms part of the Trans Pennine Trail.

Green Party Coun Ed Carlisle said last week that the situation was “maddening” for residents, with the substance thought to have killed off plants and greenery in the area. On Wednesday, Leeds City Council said those responsible have now sealed the pipes which were believed to have been the source of the leak. The pipes sit on private land belonging to GB Railfreight, who confirmed work to stop the discharge was “underway”.

In a statement, the council said: “Officers from the council attended the site today and have spoken with representatives of the land owner. At the time of visiting, the land was dry and there was no sludge or run off on the towpath or surrounding area. The company has confirmed that the pipes have been sealed and will be removed and they will be carrying out further investigations as to who is responsible.”

A spokesperson for GB Railfreight said: “We are aware of the issue at Leeds Hunslet Depot and are working with our tenants to identify the source of the discharge. Remediation is already underway and rainwater that washes across the site will no longer be channelled towards the footpath.”

The issue was first reported six months ago and although the Environment Agency was called out to assess the situation, their officers concluded it was not affecting either the health of the waterways. On Wednesday, the Agency said it had seen no evidence this had changed, but were “ready to respond” in the event of any damage to the River Aire or the canal. The Canal and River Trust had earlier confirmed it was investigating the incident.

Speaking after Wednesday’s developments, Coun Carlisle thanked those involved in fixing the issue.

“By accident, neglect, or malice, our communities are undoubtedly subject to a wide range of pollution, like this, or flytipping, or any number of other things,” he said. “But it’s crucial we speak out, get organised, and fight for a cleaner healthier city. Thanks again to all those who got involved with this case, we got a good result, but there’s a lot more still to do.”