The White House is working on an executive order to fire thousands of U.S. Department of Health and Human Services workers, the Wall Street Journal reported on Thursday, citing people familiar with the matter.

Employees at the Department of Health and Human Services are bracing for layoffs across the vast public health agency, as Donald Trump ’s administration instructs federal health officials to rank their essential workers and those who are deemed less essential.

Managers across the health agencies were tasked with categorizing their probationary workers to determine those who were not mission critical, according to two new media reports citing internal sources.