A Milwaukee alder who is seeking the Democratic nomination for Wisconsin secretary of state is calling on state officials to investigate the shipping supplies company Uline Inc.’s past use of workers from Mexico after a recent newspaper report about the practice.

Milwaukee alder JoCasta Zamarripa posted a statement on Facebook on Friday, Feb. 13, after The Guardian published an interview with a former Uline worker from Mexico. The worker said he was brought to the U.S. under a training visa but assigned to do routine work, with no training component.

Immigration lawyers told The Guardian that if the now-canceled program arranged for  Mexican workers to enter the U.S. with a training visa but instead deployed them to do regular work at the company, that would violate the law governing the training visa program.

“Wisconsin needs to demand transparency,” Zamarripa told the Wisconsin Examiner in an interview. “We need to call for an investigation and hold people accountable.”

Zamarripa, a former Wisconsin state representative from Milwaukee, now represents a South Side district in the Milwaukee city council. She’s one of three Democrats who have declared their intention to seek the party’s nomination in the August primary to run for secretary of state in November.

The Guardian story, along with previous reports from the newspaper published in December 2024 and in February 2025, alleged that Uline brought workers from Mexico under tourist visas or special training visas and put them to work in plants in Wisconsin, Florida and Pennsylvania.

Under Uline’s “shuttle program,” which ran for several years, the workers brought from Mexico were doing normal jobs in the company’s factories and were not part of a genuine training program, according to the Guardian.

In its most recent story, the Guardian reported that the newspaper’s sources said the shuttle program was discontinued in 2024, shortly after the first story was published.

Uline, based in Pleasant Prairie in Kenosha County, is a multi-billion-dollar manufacturer and seller of cardboard boxes and other shipping and office supplies. The closely held company had estimated revenues of more than $8 billion, BizTimesMKE reported in 2024, and has more than 9,000 employees with operations in Canada and Mexico as well as across the United States. Uline has not commented about any of the Guardian’s reporting on the shuttle program.

Bankrolling GOP politicians

The Wisconsin Examiner contacted Uline Monday asking for the company’s response to the newspaper’s articles and was directed to a voice mail line described as a direct message channel for the company’s co-founder and co-owner, Richard Uihlein. The other co-founder and co-owner is his wife, Liz Uihlein, the company president.

The Examiner left a voicemail message as well as email and telephone contact information. As of press time, the company has not replied.

In an interview, Zamarripa said she would call on state officials to investigate the company’s practices and potential legal violations.

Both the Uihleins have been among the top donors supporting Republican candidates closely aligned with President Donald Trump. Vice President J.D. Vance spoke at a rally at a Uline plant in Pennsylvania in December, promoting the Trump administration’s economic record.

In the 2024 presidential race, Richard Uihlein’s Restoration Pact, a Super Pac, funded a television advertisement that attacked Trump’s opponent, then-Vice President Kamala Harris, “for allowing an immigrant ‘invasion’ at the US-Mexico border,” the Guardian reported in its story that December about the shuttle program.

A 2022 report by ProPublica and the Milwaukee Journal Sentinel found that in the 2021-22 cycle the Uihleins were the top donors nationally to Republican causes in federal elections at $60 million, and spent at least $121 million on state and federal politics combined in that period.

 The couple also bankrolled political candidates who were among prominent deniers of the outcome of the 2020 presidential election, which Joe Biden won but Trump has repeatedly and falsely insisted was stolen, ProPublica reported.

Zamarripa contrasted those and other reports with the findings that the Guardian reported.

“The billionaire Uihlein family — among the biggest Republican mega-donors in the nation — have helped bankroll the very politicians, including Donald Trump, behind today’s out-of-control immigration crackdowns,” Zamarripa wrote in the statement published on the Facebook page for her campaign organization.

“Now we learn that workers in Pleasant Prairie say Mexican employees were pushed into dangerous, exhausting conditions and punished for speaking up — all while fueling Uline’s enormous wealth,” Zamarripa wrote.

Former worker goes on record

The Guardian’s 2024 and 2025 stories quoted anonymous sources “with direct knowledge of” and “ familiar with” the shuttle program as well as some unnamed Mexican workers brought to the U.S. for the program. The reports also included information from documents that the newspaper obtained.

The February 2026 story marked the newspaper’s first interview with a named former worker for the company. The Guardian reported that the worker, Christian Valenzuela, 42, shared travel itineraries from Uline documenting that he had worked at plants in Pennsylvania, Florida and Wisconsin.

The Guardian reported that Valenzuela provided a letter directed to Customs and Border Protection and signed by a Uline official. The April 13, 2023, letter sought a B1 training visa for Valenzuela. The letter also outlined a daily training schedule for him and said he would be tested on the training, according to the Guardian — but no test was ever given.

Valenzuela told the Guardian that he and other Mexican workers were paid a bonus along with gas money and accommodations while they were in the U.S. working for the company. But the wages for the visiting workers were set  at the usual Mexican wage, which the newspaper reported “was a fraction of what their American counterparts earned.”

He told the Guardian he was dropped from the program while he was in Mexico seeking treatment for an on-the-job injury at Uline during his U.S. sojourn.

The newspaper’s previous reports quoted immigration lawyers who said that the use of training visas when the visa holders were doing regular line work rather than engaging in an actual training program appears to have violated federal immigration law.

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