WASHINGTON (AP) — Immigrant farm workers would receive a raft of new protections under a Biden administration proposal to be announced Tuesday, which would boost safety requirements on farms and raise transparency around how such workers are brought to the U.S., to combat human trafficking.

The proposal would reform the H-2A visa program, under which hundreds of thousands of immigrants, mostly from Mexico, take on seasonal jobs in the U.S. agriculture industry. The number of people admitted under the program has soared in recent years, as rapid hiring after the pandemic and a low unemployment rate has left many farmers scrambling for workers.

Last year, about 370,000 people were admitted with H-2A visas, double the number in 2016 and five times as many as in 2005, Labor Department officials said. Yet as the popularity of the program has grown, so have concerns about abuses. Reports of overcrowded farm vehicles and fatalities have increased as the numbers have risen, senior department officials said.

The department is already required to ensure that the H-2A program doesn't undercut the wages or working conditions of Americans who take similar jobs. Employers are required to pay minimum U.S. wages or higher, depending on the region.

"This proposed rule is a critical step in our ongoing efforts to strengthen protections for farm workers and ensure that they have the right to fair and predictable wages, safe working conditions and freedom from retaliation," said Julie Su, acting secretary of Labor, in a statement.

The new rule, which is subject to a 60-day comment period, seeks to make it easier for labor unions to contact and interact with the H-2A workers, and to protect the workers from retaliation if they meet with labor representatives. The workers would be allowed to have visitors, including those from labor groups, in employer-provided housing, for example.

The rule would also require farmers who employ H-2A workers to provide seat belts on vans that are often used to transport workers long distances. Transportation accidents are a leading cause of death for farm workers, according to the department.

And in a step intended to counter human trafficking, employers would be required to identify anyone recruiting workers on their behalf in the U.S. or foreign countries and to provide copies of any agreements they have with those recruiters.

Another visa program, the H-2B, which allows temporary workers in fields other than agriculture, already includes similar requirements, department officials said.

"We're putting together a series of new protections or clarifying protections to make sure that workers in the program can really advocate on behalf of themselves, and that...will help prevent the problems that we're seeing with exploitative conditions," a senior Labor department official said.