It’s tomato season and Lidia is harvesting on farms in California’s Central Valley.

She is also anxious. Attention from U.S. Immigration and Customs Enforcement could upend her life more than 23 years after she illegally crossed the U.S.-Mexico border as a teenager.

“The worry is they’ll pull you over when you’re driving and ask for your papers,” said Lidia, who spoke to The Associated Press on condition that only her first name be used because of her fears of deportation. “We need to work. We need to feed our families and pay our rent.”

As parades and other events celebrating the contributions of workers in the U.S. are held Monday for the Labor Day holiday, experts say President Donald Trump’s stepped-up immigration policies are impacting the nation’s labor force.

More than 1.2 million immigrants disappeared from the labor force from January through the end of July, according to preliminary Census Bureau data analyzed by the Pew Research Center. That includes people who are in the country illegally as well as legal residents.

Immigrants make up almost 20% of the U.S. workforce and that data shows 45% of workers in farming, fishing and forestry are immigrants, according to Pew senior researcher Stephanie Kramer. About 30% of all construction workers are immigrants and 24% of service workers are immigrants, she added.