The 18th century coach house and stables off Wick Road in Bristol is up for auction and comes with six acres of land in an area known as Nightingale Valley.
But locals say the valley and woodland is also home to hundreds of rusting, sinking and overgrown barrels of tar dumped there around 1924.
Dubbed the 'Tar Barrels of the Nightingale Valley' they lie in a wood leading from Wick House - which is not part of the sale - to a local brook.
Residents say the area is full of barrels with a 'gloopy, watery tar mess'.
A local conservation group says whoever buys the site will also purchase ''a million pound problem''.
The barrels contain what is thought to be tar or bitumen and were dumped between 1924 and 1929.
During hot summer months locals say the tar melts and oozes out of them.
This Wednesday the old coach house and a courtyard of stables that was once part of Wick House is on sale with a guide price of 350K.
Jackie Friel, of The Friends of Brislington Brook, said Nightingale Valley it is still a wildlife haven full of birds and animals.
She told Bristol Live: “We have been aware of the problem for many years that one particular stretch of land within Nightingale Valley is a historic dumping ground.
“It will cost getting on for a million pounds to put this tar barrel site right.''
The group also said: ''On the one side of the stream, it just looks like any other parkland.
''But on the left-hand side of the stream, it’s like you’re walking on melted tar,.
“It’s a heavily used and very beautiful nature reserve – with newts and frogs and all kinds of lovely wildlife.
“But every summer, the tar flows closer to the stream, and nobody really knows what’s underneath it.
''At some point in the future, there may be a melting incident, which will release some stuff under the ground, then creating an ecological problem.”
The Friends have pressured the council to try and clear the land and want to work with the new owners to help sort it.
Hundreds of people have also signed a petition calling for action.
One said: ''This has been ignored and overlooked for to long and is and always has been a eyesore to what is a lovely local beauty spot.''
Another posted: ''NEEDS SORTING ASAP!''
One said: ''We used to live right by Nightingale Valley and walk here often.
''It was and is a tragedy and outrage to see tar barrels carelessly and callously dumped there onto the banks of the stream.
''A lovely area enjoyed by many but spoiled by this environmental pollution.''
Estate agent Hollis Morgan said its current owners had disclosed everything they needed to.
A spokesman said: “Our clients have taken legal advice and are confident they have disclosed all the relevant information required to sell the land in the online legal pack.
''“However, we have passed on the concerns to our client and if any further information is required it will be added to the Legal Pack.
''To clarify the situation, the contractual position on any auction sale is ‘buyer beware’ and it is up to buyers to undertake their own investigations on any property before committing to that purchase.''
Sale brochure documents include an Environmental Search of Bristol City Council, which doesn’t have the tar barrels listed.
That is possibly because it is not an official landfill site.
Previously Bristol City Council said it is limited in what it can do as the land’s owner cannot be traced.
In 2022 Bristol City Council said that numerous water and soil tests have been carried out over the past two decades, but they have not identified contaminations serious enough to enforce a clean-up.
Then, a council spokesperson added: “With an increase in visitors and use of the area since the pandemic we’ve seen the degradation of the tar barrels accelerate.
“This combined with the warm weather during the summer caused the contents of the barrels, which when left undisturbed remains solid, to become sticky and mobile.
“We continue to explore other enforcement options, but as we’re limited in what we can do by the powers currently available to us we are attempting to identify the landowner so we can work with and encourage them to take action.”
Also in 2022 The Environment Agency took samples of the stream in Nightingale Valley saying analysis showed they are “unpleasant” but “not of immediate concern”.
It added they put down some booms “as a precaution to prevent the pollution from reaching the watercourse”.
Theories about where the tar comes from includes that it came from Wick House which once had links to a local paint firm.
In 1881 Thomas Harding, a paint manufacturer, purchased Wick House and 60 acres of pleasure grounds much of which was in Nightingale Valley.
His business, Colhurst & Hardings, was situated at the Paintworks - then known as Pheonix Wharf - which was built in 1850.
The historic coach house and stables were built in approximately 1790 for the Wick House Manor.
The listing said: “A Freehold period coach house, stables, 6 garages plus various outbuildings comprising 6714 Sq Ft occupying a plot of approximately 6 Acres which slopes across the Nightingale Valley and down towards the Brislington Brook with vehicular access via a lane from Wick Road.
''We understand the Stables and Coach Houses were built c1790 for Wick House Manor. Various additional barns ( breezeblock and dutch plus a grain silo ) were built in the 1960’s when the property was operating as a Corn and Forage Merchants ( selling animal feed ). Since the business closed late 1990’s the Old Stables and Coach Houses have been used for storage.
''The property is located close to the vibrant Sandy Park high street within the popular suburb of Brislington.
''Local amenities and services are all within close proximity including convenience stores, cafes, bars and restaurants. Bristol City Centre is approximately two miles away.”