Asylum seekers were placed on the Bibby Stockholm barge at Portland Port the day after the Home Office was told about the discovery of initial results indicating that the Legionella bacteria was present, it is understood.
The revelation comes after all 39 of those on board were removed on Friday and placed in alternative accommodation.
Samples from the water system showed levels of Legionella bacteria, the Home Office said. This bacteria can cause a serious type of pneumonia (lung infection) called Legionnaires' disease.
All 39 - who only arrived this week beginning on Monday - were being taken off as a precaution.
It is understood Dorset Council told department officials on Wednesday evening about the discovery of initial results indicating that the bacteria was present, but the transfer of a further six migrants on to the barge still went ahead on Thursday.
This may just be me nitpicking- but the country is being ran being stupid f**king imbeciles