A man has been arrested on suspicion of fraud, money laundering and environmental offences linked to the huge illegal waste site in Wigan.
It's understood to be the first arrest related to the site in Bickershaw - which contains an estimated 25,000 tonnes of rubbish.
The Environment Agency says the 58-year-old from Birmingham was arrested by West Midlands Police on Tuesday.
Sky News understands that the man was arrested on a return flight from Alicante, Spain.
The suspect - whose arrest also relates to other illegal waste sites in England - has been released on conditional bail pending further investigation.
Sky News was the first media organisation to speak to a mother living next to the site - who described how her home had become a "prison" infested with rats.
Ian Crewe, area director for the Greater Manchester, Merseyside and Cheshire at the Environment Agency (EA), said: "The illegal dumping at sites across England are an attack on our communities, and the Environment Agency shares their disgust at these horrendous crimes.
"Our teams have been working relentlessly on this investigation, and yesterday's arrest are a vital step in collecting new evidence and progressing it further."
Read more:
Inside Britain's mega rubbish dumps
New illegal waste site discovered
The announcement comes after Sky News revealed last week that three new major waste sites totalling 120,000 tonnes are under investigation by the EA in Kent, Nottinghamshire and Berkshire.
The EA is currently monitoring more than 500 active illegal waste sites and has recently announced a new, tougher permit system to stop criminals registering as waste carriers.
Environment Secretary Emma Reynolds said: "We are cracking down on waste criminals - putting an end to the damage they cause, by boosting funds to tackle waste crime, putting more boots on the ground and giving stronger powers to our enforcement teams.
"If you dump waste illegally, we will come after you."
(c) Sky News 2026: Man arrested for offences linked to huge illegal waste site in Wigan
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