The site covers 6.5 hectares along the Herentals-Bocholt canal, and aside from asbestos contains PCBs, toluene, mineral oil and heavy metals. The work will take until 2011 and cost €6 million. After the Carcoke plant in Zeebrugge, which cost €20 million, the Balmatt site is the second-biggest job the OVAM has undertaken. "It will be a mammoth task," an agency spokesman said.

Several attempts were made to clean the site in the 11 years since the plant closed, but the scale of the job made it economically impossible until the site came into the hands of the Flemish region. Once cleaned up, the site will be the home for new industries, Flemish minister-president Kris Peeters has unofficially revealed, including the Flemish Institute for Technological Research (VITO).

The OVAM is currently employed in cleaning up no fewer than 525 sites across the region, mostly of much smaller size. The agency's aim is to have the soil of Flanders clean by 2036.

Meanwhile last week it was revealed that soil contaminated with asbestos and other pollutants was supplied by a recycling firm to the site in Tessenderlo of a new electricity generating station. The recycling company claims error, but the prosecutor of Mechelen has opened an investigation following testimony from two former employees that pollutants were regularly mixed with recycled soil.