The National Institute of Justice (NIJ) within the Office of Justice Programs (OJP) at the U.S. Department of Justice funded a study, "Looking for a Hidden Population: Trafficking of Migrant Laborers in San Diego County." The study, which was conducted by San Diego State and does not necessarily represent the official position or policies of the United States government, found that about 31% (approximately 38,000) of unauthorized Spanish-speaking workers have "experienced an incident that meets the legal definition of human trafficking."
The researchers studied the six most common labor sectors in which migrant laborers usually find work. They found that construction, food processing, and janitorial/cleaning were "the top three business sectors with trafficking violations and abusive labor practices." Construction had the highest rate of reported trafficking violations (35%) and abusive labor practices (63%), while agriculture, which employs most undocumented laborers in the northern part of San Diego, had the lowest rate of both reported trafficking violations (16%) and abusive labor practices (27%).
To download a copy of the study, go to: https://www.ncjrs.gov/pdffiles1/nij/grants/240223.pdf