Not surprisingly, more than two-thirds of the new arrivals had no health insurance, compared with only 44.8 percent of long-term immigrants, 22.5 percent of Mexican-born Americans and 12.3 percent of U.S.-born whites.

The low utilization of emergency rooms comes despite high occupational hazards, the report said. Eighty-three percent of new arrivals are manual laborers — working in jobs like construction and food preparation and farm work.

Fausta Hernandez, who migrated from the Mexican state of Guanajuato to Salinas, Calif., in 1971, said new arrivals are less likely to use emergency rooms because they worry they might be deported and are unable to pay. Some who speak indigenous language struggle to understand translators.

"Some of them have very serious problems but they won't go," Hernandez, 45, said in a phone interview. She has $30,000 in medical bills for having a uterine tumor removed four months ago. Insurance from her husband's employer, a mushroom packer, only picked up about half the tab.

Margarita Hernandez, 40, who came to the United States 20 years ago from the Mexican state of Michoacan, said the U.S. health care system can be daunting to new arrivals. Hernandez worked in a laundry and packed cauliflower before she was diagnosed with lung, neck and spinal cancer.

"They're very confused about the system," she said in a phone interview. "They also don't go because they don't want to get bad news."