Baldomero Orozco-Juarez was slicing chicken meat into tenders at a poultry processing plant in Carthage, Miss., when immigration agents stormed in with guns drawn. Some workers tried to flee. There was nowhere to run.

Mr. Orozco-Juarez was arrested, along with dozens of other undocumented workers at the plant. He was held in federal detention for 10 months before being put on a plane to his native Guatemala.

The raid was one of many carried out across Mississippi that day in August 2019, part of the largest workplace sweep in more than a decade and the biggest under President Donald J. Trump. Immigration and Customs Enforcement took 680 people into custody at poultry plants across central Mississippi.

Now, in his bid to return to the White House, Mr. Trump has pledged to deport millions of people in what would be the largest such effort in U.S. history. Workplace raids similar to the 2019 sweep in Mississippi would be a key element in large-scale deportations, his advisers have said.

But five years after the Mississippi raids, Mr. Orozco-Juarez, 40, is back in the United States, living in Carthage. Gone for 19 months, he said he was determined to find a way back to his family. Today, he works at a different chicken plant, paid $12.50 an hour to clean blood and meat scraps from the machinery used to debone carcasses. He now has a work permit, but he still faces the possibility of deportation, and he has been speaking out about the conditions many undocumented workers endure.