Mass workplace arrests of immigrant employees suspected of living in the US may just become a thing of the past as federal immigration agents will end the practice. Such arrests will only be done with legal permission, according to a memo issued on Tuesday by Homeland Security Secretary Alejandro Mayorkas.

The agents will instead focus will shift to pursuing “unscrupulous employers who exploit the vulnerability of undocumented workers”. The emphasis will be on fighting worker abuse including employers paying substandard wages, unsafe working conditions, and human trafficking.

Mayorkas has asked the heads of Immigration and Customs Enforcement, Customs and Border Protection and Citizenship and Immigration Services to draw up a plan within two months to increase employer penalties, encourage workers to report unscrupulous practices without fear, and coordinate with other agencies, such as the Department of Labour, the Associated Press reported.

Former President Barack Obama largely avoided such operations, limiting workplace immigration efforts to low-profile audits. President Donald Trump’s administration on the other hand encouraged such raids. The memo is being seen as an effort by the Joe Biden administration to revert back to the policy of the Obama administration.

“The deployment of mass worksite operations, sometimes resulting in the simultaneous arrest of hundreds of workers, was not focused on the most pernicious aspect of our country’s unauthorized employment challenge: exploitative employers,” Mayorkas wrote in the memo.

“These highly visible operations misallocated enforcement resources while chilling, and even serving as a tool of retaliation for, worker cooperation in workplace standards investigations,” the memo added according to the Associated Press.

Along with ending mass worksite arrests, Mayorkas said immigration authorities should also immediately start using “prosecutorial discretion” when it comes to encouraging workers to speak up about workplace exploitation and preventing employers from using retaliatory threats of deportation.

Workers’ rights groups applauded the move, saying immigrant workers, particularly those without legal permission to live in the US, are especially vulnerable. Industries such as meatpacking and chicken processing are particularly reliant on immigrant labor for backbreaking work often set in rural areas with limited access to attorneys.

During the initial weeks of the pandemic, Trump ordered meatpacking plants to remain open amid concerns about the nation’s food supply, even as COVID-19 outbreaks were closing plants.

The largest single-worksite raid in US history was in 2006 when immigration agents swept Swift & Co. plants, netting about 1,300 immigrant worker arrests.