Ministers have denied that half a million tonnes of granite waste dumped into an artificial lake that is part of a nature reserve in Gelderland has caused environmental damage, broadcaster NOS reports.

The reaction comes in the wake of a broadcast by television current affairs programme Zembla which said a permit for the dumping was initially refused by officials for environmental reasons before being pushed through by senior civil servants.

In their statement, environment minister Stientje van Veldhoven and infrastructure minister Cora van Nieuwenhuizen deny that the permit to dump the waste was pushed through despite concerns that toxic substances could leach into the water.

Van Veldhoven and Van Nieuwenhuizen cited a number of different investigations into the environmental impact of waste, a clay-like substance left over when granite and sand are crushed and prepared for road building, saying that no harmful effects had been found.

They did, however, announce a ‘review’ into the matter to relieve the anxiety among the local population, NOS said. The new investigation will be carried out by a bureau which has not been  involved in the previous investigations into the effects of the granite waste, the ministers said.

Meanwhile the practice will not be stopped, despite a request from local council West Maas and Waal, where the lake is situated. ‘An ongoing project can only be legally halted it does not comply with the legal requirements and that is not the case here,’ NOS quotes the ministers’ statement as saying.

The ministers admitted that ‘discussions about the status of the waste within the government took too long’ and that the responsible minister ‘should have been apprised of the issue sooner’.