26 cube containers of toxic diesel sludge were discovered on the Armagh Road on Friday morning.
Louth County Council confirmed the sizeable discovery earlier today. Council contractors are dealing with the issue, the local authority say. Initially, it was thought that a total of 22 cube containers had been discovered.
An IBC (Intermediate Bulk Container) can hold up to 1,000 litres of sludge each. It is understood each container was full at the time of discovery.
This is not the first occasion over 20 containers have been dumped on the Armagh Road.
A similar size discovery was made in 2012 with 22 IBC's dumped and Dundalk and the surrounds have seen multiple smaller incidents in recent times.
Louth County Council have overseen a reduction in the number of toxic sludge dumping cases between 2014 and 2016. Two years ago, there were 48 incidents dealt with compared to 106 in 2014.
The number of IBCs found in 2016 was 136, with 454 discovered in 2014