Gardai are investigating an incident in which suspected human excrement was smeared all over an Irish Water registration form before it was mailed to sub-contractors.
Two staff at the Cork-based office processing sub-contractor had to be given precautionary medical tests after the letter was opened and handled before it was realised precisely what it contained.
The company, which handles back office functions for other State bodies including the Revenue Commissioners, is expected to make a statement on the incident later today.
One staff member received precautionary medical treatment after handling the letter because they had a cut on their hand.
Another staff member, who spotted the letter after their colleague had shouted in horror after handling it and realising what it contained, immediately felt ill and complained of faintness.
Both received medical assessments though both are expected to be fine.
However, the matter was taken extremely seriously by company management and gardai were notified.
The letter was seized and is now undergoing forensic tests to try to determine its precise origin.
A name was included on the form but it is unclear whether that is the correct identity of the person responsible for smearing the excrement on the document.
The incident occurred just two weeks after Environment Minister Alan Kelly and Irish Water boss John Tierney visited the complex to show solidarity with processing staff.
The levels of abuse and intimidation towards staff handling Irish Water forms is so great that staff asked not to be identified by media organisations covering the ministerial visit.
Staff also revealed that the excrement-smeared letter, while revolting, is not the first abusive contact received by workers from members of the public furious over water charges.
Insulting material included with previous Irish Water forms have included vicious notes, used tampons and, in one case, used razor blades.
One Irish Water sub-contract worker, who asked to be unnamed, said it is not unusual to see staff breaking down and crying on a weekly basis such is the level of vitriol being directed at them.
"I am in my 40s and have children and it takes a lot to faze me. But even I have ended up crying on a couple of occasions such is the abuse you have to deal with over the phone," she said.