PFOS spilled out of an airport fire truck after it over-turned in 2002
Reassurances that Guernsey's drinking water is safe have been made following calls for a full public inquiry into pollution incidents at the airport.
Perfluorooctane Sulfonate (PFOS), used in fire-fighting foam, made its way into streams and wells after an airport fire truck overturned in 2002.
Calls for an inquiry came over concerns about a link between PFOS and cancer.
Director of Water Services at Guernsey Water Andrew Redhead said the water was safe and there was nothing to hide.
Deputy David de Lisle, who called for the inquiry, said: "Apparently it doesn't just degenerate, it actually accumulates in the body, it needs to be looked into further. It's not good enough to say the dilution in the water makes it safe."
Guernsey Water has insisted the levels of PFOS are not dangerous.
Mr Redhead said: "We went to extraordinary efforts to ensure the fire-fighting foam avoided the St Saviour's Reservoir and discharged down stream.
"Ever since 2007 Guernsey Water has carried out rigorous tests, far more than is required, both in the distribution network and people's taps."
Minister Bernard Flouquet from the Public Services Department, who has responsibility for the airport fire service, said a public inquiry would have no benefit other than to confirm that the department had acted appropriately and responsibly.
He said: "All it would do is confirm that the operational use of fire-fighting foam containing PFOS at Guernsey Airport was appropriate at the time, and the measures taken by Guernsey Water to protect the water supply have been appropriate and successful."
"Stocks of fire-fighting foam containing this chemical have been phased out at Guernsey Airport now that a suitable replacement has become available," added Deputy Flouquet.