Heaps of toxic material have been dumped in country lanes in rural Preston.
Asbestos was discovered fly-tipped in two sites in Lea and Cottam, believed to have come from the same source.
Community leaders have slammed the tipping as “outrageous” and endangering lives, and have urged anyone with information to come forward.
Officers at Preston Council were contacted on Tuesday evening with reports of dumped asbestos on a single-track road off Sandy Lane in Cottam, and also on Darkinson Lane in Lea.
Experts believe they both came from the same place, and have asked anyone with any details to contact the council.
Preston Council’s cabinet member for community and environment, Coun Robert Boswell, said: “This action is not only illegal and inconsiderate to the local community but, being asbestos, is also very dangerous.
“The council will prosecute with vigour anyone caught fly-tipping.
“The waste will have to be removed at considerable expense to the tax payer.
“I would urge anyone with information on who could have done this to contact the council on 01772 906909.”
Coun Christine Abram, who represents Lea ward, described the dumping as “horrendous”.
She said: “Apart from the fact they are dumping it, it’s a health hazard. They are risking people’s lives.
“Whoever is doing it needs prosecuting, it’s absolutely terrible.
“It’s not just fly-tipping, it’s beyond fly-tipping, it’s endangering lives of people and animals, and somebody will have to clean it up.
“The Sandy Lane one is not far from the nursery and where they are building the new houses, that’s outrageous.
“I can’t imagine how anyone could be so vile.”