Scientists have to workthroughthenight to collect biological samples during the brief hours of darkness when the phytoplankton is not photosynthesizing.
The contamination was discovered late last night and the committee has been told that thework had been done throughthenight to ensure that the hole is pumped clear.
"We will continue to work diligently throughthenight in an effort to bring closure to this incident as quickly as possible, " the Dale County Sheriff's Department said at 11 p.m.
The council said it had arranged for letters to be delivered to all 600 households in Fairlie informing them of the situation and making them aware that some noise disturbance is likely throughthenight while work is ongoing.