A 'devastating' cyanide spill killed an estimated 2,000 fish in a pond, forcing the authorities to 'seal off' the area.
Toxic liquid poured into the pond after it spilled out of a ruptured tank at a nearby industrial estate in Heanor, Derbyshire, a fishing club said.
The poisonous chemical flowed down the road and into a drain before reaching Adam's Pond at Shipley Country Park.
The National Coal Board No.5 Area Fishing Club, which leases the pond, knew something was wrong when dead fish started 'popping up'.
A cleaning company has now paid the club £20,000 in an out-of-court settlement over the spill.
Gary Shelbourn, secretary for the club, said members were left 'devastated' by the incident.
He told the Mirror: "The company involved accidentally dropped a container that had cyanide in it.
"They were unloading a delivery of cyanide solution in the car park to take it into the factory. It ended up being spilt and it went straight down the drain.
"The first thing we knew about it was when we started to see fish popping up. An emergency call was made to the Environment Agency and they came down and did tests.
"They sealed it off. There was a danger to the public. It's cyanide at the end of the day, the whole place was cordoned off.
"We lost quite a few fish, it killed a couple of thousand. A lot of them never came up to the surface.
"Around 20 per cent of the fish that were in the pond died."
Mr Shelbourn, 54, said that although the substance in the pond was 'nasty', it was not nearly as deadly as the cyanide featured in the James Bond films.
He added: "The feedback we got was that you would have to stick a glass in the pond and drink it for it to become a problem for you."
Mr Shelbourn added that there was no risk of members being poisoned as they do not eat fish caught from the pond, which is stocked with roach and coarse fish.
The club worked with the not-for-profit organisation Fish Legal to launch a civil case against the cleaning company following the spill in February 2018.
Mr Shelbourn said the club showed it had lost earnings through a drop in day and season ticket sales after the forced closure of the pond.
The pond's fish stock also dropped dramatically due to the spill.
Earlier this month the cleaning company paid the club £20,000 in an out-of-court settlement.
“The club is a non-profit organisation, and the money will be reinvested into projects such as planting new wetland plants and reed beds to serve two purposes," Mr Shelbourn said.
"The first is to aid the filtration of the waters that run into the lake and the other is to provide more habitat for fish and wildlife. We also plan to create new paths and more easily accessible fishing platforms.
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"We have some hard work ahead, but we are certain Adam's Pond will be much improved and better protected from future incidents in the coming months.
“We would like to thank the company who had the unfortunate accident for a speedy conclusion... They can rest assured that the money will be well spent in restoring the fishery.”
The pond has suffered previous pollution incidents, although none of them were as serious as the cyanide spill, Mr Shelbourn said.
He thanked Fish Legal and the Environment Agency, which has restocked 3,000 fish since the spill, for their support.
Andrew Kelton, a solicitor for Fish Legal, said: “This case shows that it is possible for anglers to conclude a civil claim for pollution even before the Environment Agency has finalised its enforcement action and released its evidence.
"This is particularly important now given the backlog in Environment Agency investigations and enforcement action caused by Covid.
"The defendant company, to give it its due, accepted the inevitable that it would have to compensate the club at an early stage and helped bring about an amicable settlement.
"Although we do not consider that naming the company would prejudice any investigation or subsequent enforcement action by the Environment Agency, we have not put that information in the public domain out of an abundance of caution as to the requirements of the prosecution process."
An Environment Agency spokesperson said: “We can confirm that we are at an advanced stage in the investigation of a cyanide pollution incident at Adam’s Pond in Shipley Country Park in Derbyshire in February 2018 and are pursuing an enforcement outcome.
"As this is a live investigation we are unable to comment further.
“We take all reports of pollution seriously and members of the public can report environmental incidents to our 24/7 hotline on 0800 807060.”
The National Coal Board No.5 Area Fishing Club was founded in 1947 as a way to help miners enjoy the fresh air.
Although the National Coal Board became British Coal Corporation in the 1980s, the fishing club stuck with its original name.
