Nearly one-third of the illegal immigrants interviewed by researchers reported working with harmful substances and in dangerous conditions, while 19 percent said they were not given any protective equipment, according to the study by professors at Tulane University and the University of California at Berkeley.
Illegal immigrants also were paid significantly less — if at all earning on average $10 per hour, compared with $16.50 for documented workers, the study said.
"What is fundamentally unfair is these are workers who have responded to a national priority to rebuild this city and yet whose rights are being violated," said Laurel Fletcher, director of Berkeley's International Human Rights Law Clinic and one of the study's co-authors.
Under federal labor law, illegal immigrants are afforded the same health and safety protections as documented workers. And regardless of their legal status, laborers can sue most employers under the Fair Labor Standards Act for violation of the minimum wage law and overtime regulations, according to the researchers.
The federal Occupational Safety and Health Administration said it has conducted more than 7,000 on-site inspections in the New Orleans area.
The U.S. Department of Labor said it was concerned about wage and safety violations and had hurried to establish a Gulf Coast office.
"I'm not surprised that there are wage violations in the whole Gulf Coast rebuilding area — all of the conditions are there for that to occur," said Victoria Lipnic, assistant secretary of labor for employment standards. "But we've tried to be very proactive in our enforcement effort."
Before last year's hurricane, Louisiana had one of the smallest Hispanic populations in the country — 2.5 percent of residents compared with 12.5 percent nationally.
Census data indicates nearly 100,000 Hispanics moved to the Gulf Coast region following Hurricane Katrina, lured by promises of high wages and plentiful work. It is unclear precisely how many have come to New Orleans, though the study estimates one-quarter of the construction workers in New Orleans are illegal immigrants.
They are now the backbone of the reconstruction, converging at dawn on the city, waiting to be picked up for 14-hour shifts hauling debris, ripping out drywall and nailing walls. Because so many are here illegally, the study says, they are especially vulnerable to exploitation.
To make his point, Alberto Mendoza holds up his lined, calloused hands, proof of the hard and unprotected work he has been performing. "No gloves, no goggles — no nothing," said the 40-year-old illegal immigrant from Mexico City.
In his pocket, he keeps a jagged piece of paper inscribed with the word "Pam" and a cell phone number, his only lifeline to the woman who hired him.
"She took me to the house and said: 'Do this. Do that.' Then she left us there. We worked all day. She never came back to pay us," said Mendoza, sitting in a traffic median Monday, waiting for another job.
Twenty-eight percent of illegal immigrants interviewed said they had problems getting their pay, compared with 13 percent of those here legally. More than a third said they were paid less than they were promised, and few said they were paid for more than 40 hours in one week.
While 83 percent of documented workers interviewed by the researchers said they received medical attention when needed, only 38 percent of illegal immigrants did.
Around one-third of illegal immigrants said they understood the hazards of removing asbestos or mold, compared with more than 65 percent of documented laborers.
Some of those waiting for work said they are afraid of complaining.
"It's too dangerous for my body," said 29-year-old Saul Linan, an illegal immigrant from Guanajuato, Mexico. "But I don't say anything. If I do, the boss says, `Hey, if you don't work hard, I'll take you to immigration.'"