Hurdles and headaches for companies that defy the White House push to end work authorization program.

Major U.S. companies, including Microsoft, Facebook and Apple Inc., have pushed back againstthe Trump administration's plan to rescind the Obama-era authorization program that allowed an estimated 800,000 undocumented immigrants to remain in the country.

Yet, if the Deferred Action for Childhood Arrivals program is terminated and Congress doesn't craft new rules, any defiant companies that move to shield workers from deportation could be exposed to compliance headaches and legal hurdles, employment lawyers said.