Schiphol airport paid €30,000 in a settlement with the public prosecution office to avoid being taken to court over its role in a spill of firefighting foam containing 134 kilos of highly toxic PFOS, its annual report has revealed.

A technical malfunction of a sprinkler installation at a KLM hangar in 2008 caused thousands of litres of foam to leak into the environment.

The airport admits it did not want the case to come to court, but refuses to reveal the contents of the agreement, the Telegraaf reported on Monday.

The foam contained PFOS, one of thousands of per- and polyfluoroalkyl substances known collectively as PFAS. They are currently under scrutiny because they are “forever chemicals” which accumulate in drinking water and, as well as damaging the environment, can cause cancer and affect the immune system.

PFOS was already banned in 2006 but old stock was allowed to be used up until 2011.

Drainage leak

When the spill occurred the foam made its way to the wastewater processing installation via drainage ditches, but it was only when the local water authority Rijnland became aware of the danger some days later that the foam was directed into designated basins.

Disastrously, the basins had sprung a leak, allowing foam to leak into the environment for months, eventually leading to a costly clean-up operation.

Schiphol denied responsibility because the firefighting facilities and hangar were not the property of the airport.

Schiphol said there is currently no “legal procedure” concerning the incident and that in 2013 the airport paid €30,000 to avoid  “a lengthy court case”.

Some 16 years after the incident the area surrounding the airport is still recording extremely high levels of PFOS, the Haarlems Dagblad reported.

Schiphol depots contain some 200,000 tonnes of contaminated soil, part of which was caused by foam. The airport is planning to clean up this soil on the premises using a dedicated installation. It is also going to build an extra depot for soil contaminated with PFAS.