The DPP is believed to have recommended a prosecution in relation to alleged illegal dumping on a large site in County Louth.
The estimate of the volume of toxic sludge residue from diesel laundering dumped at the site has now been increased to 500 tonnes.
This has prompted Louth County Council to tender for specialist contractors to properly dispose of the material.
A council spokesperson said: “we have had to tender for suitable qualified contractors to take the waste away. The bulk of it is household waste. This is not a new find.”
When the dump was found in August 2011 there were concerns about its proximity to the Cavanhill water treatment plant that serves Dundalk town. The county council said there is no threat to the supply.
The spokesperson added that last year the council removed, through contractors, 600 tonnes of toxic diesel sludge and so far this year: “we have had 68 incidents and processed 400 tonnes”.
Detectives from Dundalk completed a file for the DPP following an investigation into allegations of illegal dumping.
It is understood that the DPP plans to progress its prosecution before the end of the year.
The tender document calls for the specialist contractors to remove "unauthorised infilled waste material from a quarry site located in north County Louth under Section 56 of the Waste Management Act 1996 as amended due to concerns of environmental pollution occurring on this site."
“The source of the hazardous material is believed to be from activities relating to the laundering of marked diesel fuel.”
It also refers to some 100 cubic metres of waste liquid which is believed to refer to a pond at the bottom of the quarry.
To date all of the costs of recovering, repackaging and disposing of the sludge, which is hazardous waste are paid for by local authorities.
This is then recouped from the Department of the Environment.