President Donald Trump's decision to end a program that protects hundreds of thousands of people who were brought to the U.S. illegally as children could cost the economy hundreds of billions of dollars over the next decade.

Attorney General Jeff Sessions on Tuesday announced the "wind down" over the next six months of the Deferred Action for Childhood Arrivals program, which shields some 800,000 young immigrants from deportation. Unless Congress acts to replace the Obama-era program with similar protections, those people would no longer be allowed to work in the U.S.

The loss of those workers, and the paychecks they earn, would dampen the American economy, hitting hardest in states like California and Florida with the largest share of DACA participants, according to groups that support the protection of those immigrants from deportation.