As Houston struggles to rebuild homes and businesses that were destroyed by Harvey, the sprawling metropolis’ day laborers—many of whom are toiling in dangerous conditions amid fear of being picked up by immigration authorities—are facing a harsh reality.

Guillermo Miranda Vazquez starts his day in a parking lot near the Home Depot where he easily finds work alongside other day laborers, the Associated Press reported.

Miranda clears rotted drywall, hauls out rotting furniture, chops damaged trees or helps lay the foundations for new homes. Often he’s wearing only a T-shirt, work pants and tennis shoes while surrounded by the pungent stench and raw sewage that flowed into homes during the flooding.

“I always wash and scrub myself, and I use alcohol or something similar so that I don't get infected,” said Miranda, a native of Guatemala. “I haven't gotten sick yet.”

Harvey damaged or destroyed 200,000 homes and flooded much of Houston and smaller coastal communities with record amounts of rain and high winds. It also created a massive demand for the kind of work that day laborers have long performed after hurricanes and tropical storms.

Day laborers interviewed by the Associated Press said they've been hired by a mix of individual homeowners, work crews from out of state, and subcontractors. Mostly immigrants, they operate in plain sight, gathering early in the morning in parking lots near construction stores and gas stations.

Nik Theodore, center, a professor at the University of Illinois at Chicago, interviews day laborers cleaning up after Hurricane Harvey about their work conditions in Houston. (AP)

Advocates from the National Day Laborer Organizing Network recently fanned out to these sites to survey the workers about the conditions they're experiencing. Interviews suggested most are routinely exposed to mold and contamination, and aren't aware of legal protections they have even if they're not in the country legally. Advocates have been passing out flyers with information.

About a quarter of the more than 350 workers surveyed said they had been denied wages promised for cleanup work after Harvey, sometimes by employers who abandoned them at work sites after they had completed a job, according to a report on the survey by Nik Theodore, a professor at the University of Illinois at Chicago. Around 85 percent had not received safety training.

AFTER HARVEY, WHAT WILL HAPPEN TO THE HUNDREDS OF THOUSANDS OF FLOODED CARS?

More than 70 percent of the day laborers are in the U.S. illegally, some of them having previously been deported, the survey found. Their wages have stayed at around $100 a day, according to the survey, though some individual laborers said they were being paid more after the hurricane.

The Trump administration ramped up immigration-related arrests this year and resumed field operations after Harvey. And Texas this year passed a law that prohibits police departments from stopping their officers from asking people about their legal status or cooperating with federal immigration authorities. Much of the law took effect a month after Harvey hit, when an appeals court overruled a federal judge's ruling against it.

The demand for labor has also drawn in people who are unaccustomed to the work and untrained in basic safety measures, Martin Mares, a native of Mexico who settled in Houston in 1995, said. He recently saw a pregnant woman cleaning an apartment building that had flooded without wearing gloves., the Associated Press reported.

Guillermo Miranda Vazquez, right, speaks to Francisco Pacheco, left, an organizer surveying day laborers about their work conditions in Houston (AP)

“People don't analyze it. They don't see the consequences,” Mares said. “They go to work without knowing whether the business will even pay them.”

In Houston, which has an estimated 600,000 residents who are in the country illegally, community leaders worry about the impact of immigration policies on worker safety. Even day laborers without legal residency are entitled to federal protections against wage theft and safety hazards.

"These people are scared," said Stan Marek, who owns a Houston-based construction company and has long pushed for a program to legalize workers. "They're not going to go to the police if they get robbed. It's a formula for disaster in our community."

Sitting on the curb outside the Home Depot recently, Miranda said he has often dealt with employers who didn't pay what they promised, but that he hadn't reported anyone to the police.

"This is a country where I'm here as an immigrant. I don't have anything," Miranda said. "The day they catch me, they'll deport me."

The Associated Press contributed to this story.