A significant amount of waste has been illegally dumped at two locations in Derbyshire.
Investigations are underway after the rubbish was fly-tipped at Moor Lane, Taddington, and in a lay-by off the A619 road between Bakewell and Baslow, known locally as the 13 bends.
Motorists driving on the 13 bends have reported smelling a putrid stench from the piles of waste.
Pete Haslock, enforcement team leader at the Environment Agency (EA), said: "The EA is working with the police to investigate a recent spate of these type of fly-tippings.
"There are currently two sites in Derbyshire which we are investigating.
"One is between Bakewell and Baslow and the other is at Moor Lane, Taddington.
"We don't currently know where the waste is coming from and, if anyone has any information that may help this enquiry, please call our free hotline on 0800 807060 or Crimestoppers on 0800 555111."
Referring to the waste dumped off the A619 road, a Derbyshire Dales District Council spokesman said: "The material appears to be scrapings from a plastic recycling process and contains materials that can't be recycled.
"Once the EA has been out and investigated it will fall to the district council to remove the tip using a licensed waste collector."
According to latest Government figures, there were more than a million fly-tipping incidents throughout England last year.
This led to a total clearance cost of more than £57.5million while offenders were fined a total of nearly £723,000.
Harsha Rathnayake, chief executive of the Junk Hunters rubbish removal company, said: "Fly tipping is illegal for a reason - it’s dangerous, unsightly, terrible for the environment and it costs councils tens of millions of pounds a year to clean up and they're cash-strapped enough already."