MILAN, March 31 (Reuters) - Five staff at a treatment plantoperated by oil major Eni were placed under housearrest on allegations of illegal waste trafficking, the Italianpolice said on Thursday.
The arrests, of managers and workers, are part of atwo-year-long investigation by regional antimafia prosecutorsinto waste management at the plant in southern Italy, a policestatement said.
The plant is located in the Val d'Agri oil concession areain the Basilicata Region, in which Royal Dutch Shell has a stake.
The police said part of the plant had been seized and that the alleged illegal activity had allowed the Italianstate-controlled oil major to make "an unjust profit".
Emissions from the plant's chimneys were also beyond legal thresholds and had not been declared, the police said.
In an emailed note, an Eni spokesman said the firm wouldcooperate fully with magistrates and that the company's lawyerswere looking into the matter.
(Reporting by Stephen Jewkes; editing by John Stonestreet)