The investigation into allegations regarding 13 church and state-run children's homes in Northern Ireland is being chaired by retired judge Sir Anthony Hart in Banbridge, Co Down.On Tuesday, a witness claimed he had been sexually assaulted by a woman at St Joseph's Home in Termonbacca when he was aged just five or six.He further described having been bathed in Jeyes fluid during alleged abuse in the 1950s and 60s."It was kind of like a Zyklon B gas chamber," he said.The witness was later transferred over the border to a Christian Brothers home in Galway, which he referred to as "essentially a gulag - a child's prison".The comparison was two hell holes. Which is better? It is difficult to describe when things are bad - you are on a race to the bottom. Salthill (Galway) was Auschwitz, Termonbacca was Treblinka.WitnessThe abuse inquiry, which is the largest of its kind to ever be held in the UK, is looking into cases in Northern Ireland which happened between 1922 and 1995.Alleged abuse at Sisters of Nazareth properties in Derry is already said to have included:separation of brothers and sisters, not even telling them if they were in the same homelocking in cupboards or threatening to send them to a hospital for those with learning disabilitiesforced farm labouring or working in the laundry instead of going to schoolremoval of Christmas presents and other personal itemsleaving youngsters hungry through inadequate food, or alternately force feedingforcing children to eat their own vomit when they were illThe inquiry has also heard that young people in the care homes were known by numbers rather than their names, and that they were allegedly abused, threatened and humiliated.The religious order previously made a public apology.Public hearings are scheduled to continue until June 2015, with the inquiry team then due to report to the Stormont Executive early in 2016.