Lives were put at risk by the director of a recycling centre which caught fire and burned for almost two months.
The Arcwood Recycling blaze was so fierce it could be seen for miles and caused the deaths of thousands of fish.
Luke Barker, director of the firm in Low’s Lane, Stanton-by-Dale, pleaded guilty at Derby Crown Court to four safety failures which put people “at risk of death or serious injury.”
The fire broke out in a pile of 8,000 tonnes of wood stored at the plant, which was stored too close to a gas supply, the court heard.
It cost Derbyshire Fire and Rescue Service, which spent 4,678 hours at the scene, £107,000.
The Environment Agency also paid out £200,000 on work to minimise the impact to wildlife.
Prosecutor Bernard Thorogood said: “Thousands of fish were killed – about 500lb – and 7,000lb were moved for protection.
“About 6km of the canal was damaged.”
He said there had been “a real local economic impact”, with nearby businesses having to close for two weeks or more.
The flames were finally extinguished in late October. Burning embers were buried on a nearby site and covered with a layer of foundry slag and sand.
In court, Barker admitted that he had “failed to make a suitable and sufficient assessment of the risk” to which people were exposed at the site in the case of fire.
He also admitted failing to take general fire precautions to ensure the safety of his employees and visitors.
Barker also pleaded guilty to failing to maintain fire-fighting equipment and providing employees with adequate safety training.
The fire service paid to use 118 fire engines, 19 special appliances and the hire of a JCB digger and its driver. In addition to the costs of the fire, the fees racked up by the investigation for the court case are £35,500.
Barker, who will be sentenced at Derby Crown Court on March 4, also admitted allowing fire-fighting run-off water to flow into the Erewash Canal without an environmental permit.
At its height, the blaze could be seen for miles and huge plumes of smoke drifted towards nearby houses.
Karen Sanders, 46, who was living in nearby Littlewell Lane, felt the effects of the blaze.
Speaking in September, she said: “The smoke’s been drifting. We’ve shut our windows and doors. It’s come closer, so we’re quite concerned.”
On the same day, Marilyn and Richard Dring said they could see the blaze from their home.
Mr Dring, 66, said: “I could see the fire was really gathering pace. I was dreading the wind changing direction.”
The Environment Agency rescued thousands of fish from the canal as water used to extinguish the fire began to de-oxygenate it.
Officials moved 100,000 fish by stunning them with electricity, before bringing them out using nets.
At the time of the rescue, a spokesman for the Environment Agency’s east area said: “We mobilised our teams to start moving fish by ‘electro-fishing’ to a location where oxygen levels are normal.
“We’re using hydrogen peroxide to increase the oxygen levels in large parts of the Erewash Canal.”
He said staff were using a barge with oxyjets – devices which spray hydrogen peroxide into the canal – to raise the water’s oxygen levels “uniformly”.
The spokesman added: “We have also reduced run-off into the canal by diverting the fire water to a Severn Trent Water sewer.”
A separate fire appliance worked to pump contaminated water out of the canal at Dockholm Lock to allow fresh water to be drawn into it.
Even after the flames were extinguished but the blaze was still smouldering, firefighters carried out daily checks for several weeks.
The fire was not declared to be out officially until November 15.