Review into chemical spill at Guernsey Airport development
An investigation has begun to find out how 10 litres of the chemical bitumen was spilt by the firm redeveloping Guernsey's Airport.
The substance is not believed to be dangerous, but there will be tests to see if it has entered the water supply.
When it spilled, it seeped into the soil beneath and the contaminated soil has since been taken away and will go into landfill.
Environmental Health is looking into whether it poses a risk to the public.
Lagan Construction said the spillage was "regrettable" and it was now trying to find out how to stop the same thing happening again.
Colin Le Ray, airport director, said there had been a leak from one of the feeder pipes to a tanker parked overnight on 8 November.
He said: "It was a slow leak but nonetheless created an issue which we felt had to be resolved."
Tobin Cook, deputy chief environmental health officer, said: "At this stage we haven't actually approached any of the neighbours due to the nature of the chemical that's been spilled and the extent of the spillage.
"But it is something we're continuing to monitor and obviously if at any stage there's any risk we'll be the first to make them aware of the problem."
A spokesman for Guernsey Water said it was running tests to see if there was further cause for concern.