Four Senators are pressuring homeland security chief John Kelly to reject U.S. companies’ pending pleas for visas to import up to 70,000 extra foreign workers this summer.

“A large body of evidence suggest[s] that our increasing reliance on the H-2B program cuts [Americans’] wages, pushes American workers out of jobs, and may, in some case, discourages them from every applying again,” says the bipartisan letter by Senators Chuck Grassley (R-IA), Dick Durbin (D-IL), David Perdue (R-GA), and Richard Blumenthal (D-CT).

The letter was written to Department of Homeland Security Secretary John Kelly and Secretary of Labor Alexander Acosta. In early May, the supplemental 2017 appropriations bill included language allowing the Secretaries of DHS and Labor to print roughly 70,000 additional visas for companies to import foreign workers for seasonal work in landscaping, food processing, tourism, and resorts. The underlying H-2B legislation allows companies to import a maximum of 66,000 visas for seasonal jobs that could be filled by Americans.

The appropriations language says Secretaries Kelly and Acosta should produce the extra visas if “businesses cannot be satisfied in fiscal year 2017 with United States workers who are willing, qualified, and able to perform temporary nonagricultural labor.”

The H-2B visa program has strong lobbying support from industries which rely on low-wage seasonal labor to minimize their year-round costs. For example, in March, more than 30 Senators signed a letter urging Kelly to approve more H-2B visas. The companies also complain that Americans won’t take seasonal jobs and that there is a shortage of vocational schools to train youths for skilled blue-collar work.

In Wednesday’s letter, the Senators told Kelly and Acosta that “it is essential that you carefully evaluate hiring and recruitment efforts to ensure that any proposed increase in H-2B numbers does not disadvantage U.S. workers … If Secretary Kelly does determine that American workers are not adequate to serve U.S. business needs, we request that you provide a written report to the Senate Judiciary Committee. ”

“We understand and sympathize with the needs of employers who rely on seasonal H-2B … but unless it is carefully managed, the H-2B program puts all workers at risk,” the Senators said.

The letter cites studies from the Bureau of Labor Statistics and the AFL-CIO for the proposition that an H-2B expansion may suppress prevailing wages, research supported by findings from pro-American immigration non-profits.

Robert Law of the Federation for American Immigration Reform told Breitbart News on the passage of the appropriations bill that:

Increasing the number of low skilled foreign workers through a massive government funding bill is Washington at its worst. This is a clear betrayal of blue collar Americans who were hit the hardest by the Obama economy. Even after Trump’s victory, Congress is more interested in rewarding the business lobby’s thirst for cheap workers than getting their unemployed constituents back in the work force.

The Senators said the H-2B program was providing cover for abuse of “vulnerable” foreign workers, who can be repatriated by companies if they complain about working conditions and wages.

So far, the Department of Homeland Security under Secretary Kelly has been reluctant to authorize any expansion of the H-2B program.

The H-2B program is the blue-collar version of the better-known H-1B white-collar outsourcing program, which is allowing almost one million foreign university graduates to hold jobs in the United States.