Remploy shuts in Aberdare, Abertillery, Merthyr, Wrexham
Four Remploy factories in Wales are to close on Thursday.
Sites in Aberdare, Abertillery, Merthyr Tydfil and Wrexham will shut, to be followed at a later date by Swansea, with a total loss of 189 jobs.
The UK government has claimed the £320m budget for disabled employment services could be better spent.
The Welsh government has announced a £2.4m scheme for employers who give jobs to former Remploy workers for at least four years.
Last month, Remploy officials rejected a private bid to take over the Wrexham factory, safeguarding 40 jobs.
It was also confirmed in July that five Welsh Remploy plants will close in total. Two other sites which had been at risk, at Bridgend and Croespenmaen in Caerphilly county, will remain open.
Minister for Disabled People Maria Miller has told the House of Commons: "We are doing everything we can to ensure that Remploy workers will receive a comprehensive package of support and guidance to make the transition from government-funded sheltered employment to mainstream jobs."
Roy Whitney, lead representative for Unite in south Wales, told BBC Wales it was a "heartbreaking day".
"To be honest, the company has not prepared the disabled people at all, it's been like Welsh lambs to the slaughter house.
"They say there are plans in place with the Welsh assembly, they are helping us, they have set up a task force team, but as far as the UK government are concerned they destroyed a family that has been in existence for 60 years."
Mr Whitney was not hopeful for the future.
"There is no work out there for fit people, what makes the UK government think there'll be work out there for disabled people?
"If we're here in 12 months time it'll be through the efforts of Welsh assembly and not through the efforts of the UK government - they don't care."
The factories were established 66 years ago.
And some of the workers have been employed there all their working lives like Nicholas Green, 41, from Wrexham, who started 26 years ago from school.
"I have grown up here with all the lads," he said.
"I have had no experience anywhere else so it's scary for someone like myself as I have no idea what to expect."
The last shift ends at 13:00 BST on Thursday at Wrexham.
Shadow Welsh Secretary Owen Smith said the announcement was a "real blow for those employees who have relied on stable employment in Remploy factories for many years".
"The Remploy factories are an imperfect solution for the employment needs of disabled workers but for many they've been a real lifeline and they remain, in the present climate, a source of employment in areas where jobs are increasingly hard to come by," he added.
Plaid Cymru's Hywel Williams backed the Welsh government's calls to devolve the Remploy budget.
"We can achieve a great deal in creative and worthwhile development in supported employment in Wales if the responsibility, and most importantly the resources, are transferred from London to Cardiff," he said.