The affliction described by Abdul Ahad seems more like a mystical, supernatural curse than any scientifically possible affliction. But fantasy stories are on topic as well as science fiction stories, as are mixes of genres.
One way to recruit workers and tell them the truth about the mystical curse that seems to afflict the families of workers, and still get them to agree to work, is to recruit orphans. Preferably orphans who live in orphanages because they have no extended families to take care of them, no grandparents, older siblings, uncles, aunts, first cousins, etc.
And it is possible that the organization might arrange to produce a lot of orphans without close biological relatives to ensure a steady supply of workers. But considering the vast population of the world, over 7,600,000,000 people in 2018, it seems unlikely that there won't be enough natural orphans.
It is perfectly possible for a man with no living parents, siblings, nieces or nephews, etc., to marry or have an affair with a woman with no living parents, siblings, nieces or nephews, etc., and to have one or more children and then both die, leaving the baby with no living grandparents or living descendants of those grandparents.
Of course orphans might have been raised by foster parents or adoptive parents who they may love as much or as little, it varies a lot, as people love their biological parents who raise them. So these orphans might demand proof that the curse only affects biological relatives and not adoptive relatives.
What about the possible desire of those workers to someday have children of their own who will be descendants of the grandparents of the workers and thus subject to the curse? Maybe only orphans who don't want to have children will be recruited. Maybe the workers will be sterilized so they can't have any children in the future to be cursed.
Possibly the workers will be recruited from people who might have close living relatives but don't know who they are. Some such people wouldn't want to inflict a terrible curse on people they don't know, but other, less ethical people, will be comfortable with cursing anyone who they don't already know and like.
For example, the children of prostitutes might not have the slightest idea who their biological fathers are. And their mothers might not tell them about their own families before dying, or might say that they became prostitutes because they are orphans without close relatives.
And there are foundlings, babies left on the doorsteps of institutions without any identification of their parents. Thomas O. Moonlight (1833-1899), Union army colonel and governor of Wyoming Territory, came from a Scottish family allegedly named because an ancestor was a foundling found in the moon light.
Or maybe the workers will be recruited from people who hate their families and don't care what horrible curse they unleash upon them. People who have wanted to kill their relatives and almost tried doing so. People who think that the curse won't be bad enough for what their relatives deserve.
As for the danger to the workers themselves, back in the old days when most people were poor and desperate, it was easy to recruit people for dangerous jobs. During the Age of Discovery, a long sea voyage, even to peacefully trade in a place that was already discovered and known, could result in half the crew dying during the voyage.
in modern times people in developed first world countries are not so desperate, but that still leaves billions of people in third world countries who will be desperate enough to take highly dangerous jobs in the near future, even if the organization honestly tells them how dangerous it is instead of lying.