Residents of one of Alexandria’s largest affordable apartment complexes grilled federal regulators, local authorities and their landlord Saturday over the discovery of asbestos during renovations of their homes, angrily asking why it took three months for officials to halt the work.

Owners of the 530-unit Hunting Point on the Potomac, formerly Hunting Towers, received a rare stop-work order from the Environmental Protection Agency last week after inspectors discovered asbestos in the floors, doors and windows. The agency also found that workers were not taking legally required precautions.

During four visits to the 63-year-old complex since the beginning of the year, EPA officials found crumbling asbestos in apartments, halls and trash areas where windows and floor tiles are being replaced. No notice of the danger was posted, the EPA said, and workers did not seal the area to protect residents. No certified supervisor was on the job, nor were workers certified in the task of removing hazardous materials. The EPA has ordered testing for airborne asbestos fibers.

The stop-work order is an unusual action by the EPA; only five a year are typically issued, and they rarely involve occupied apartment buildings, an EPA spokeswoman said.

The crowd of more than 100 that gathered at Alexandria’s Lee Center to hear the EPA’s explanations was angry and mistrustful of the buildings’ owners and contractors. Some responses offered by officials drew scoffs and catcalls.

“All the units should be sampled,” said resident Crystal Kilby, who is a nurse. “I live there. I don’t want my health compromised.”

“The thing I find most disconcerting is it was necessary for a resident to bring this to your attention,” Doug Meckes said. “I’d like to know where the town of Alexandria was.”

“This isn’t even negligence — this is recklessness,” said Stephanie Ackerman, who said she has been threatened with eviction for refusing to let contractors in her apartment to replace windows. Several parents testified that they worried about children who have crawled on or touched contaminated surfaces.

Steve Boyack, senior vice president of the Laramar Group, the part-owner that manages the complex, said the company had been unaware that the buildings had asbestos in them until the EPA’s stop-work notice arrived. Laramar immediately complied, he said, and will follow EPA regulations to resume work.

Residents have been complaining about the renovations, possible asbestos and lead-paint contamination and rising rents for the past year, ever since the two eight-story buildings were sold by the Virginia Department of Transportation for $81 million to Laramar and the investment fund Lubert-Adler. The residents say that the city failed to take their complaints seriously.

“Why, instead of responding to citizens and saving several months of exposure to asbestos and neurotoxins . . . why did you wait for the federal government to come in and do your job?” Chuck Benagh asked.

City inspectors who checked the plumbing work at Hunting Point last summer found no evidence of asbestos because there was no insulation around the pipes, said John Catlett, the city’s director of code enforcement.

The city did no other inspections because it lacks the authority, spokesman Craig Fifer said. He added that the city referred residents to state and federal authorities that can perform the inspections.

Other tenant complaints, lodged with the city’s landlord-tenant office, focused on a lack of notice given by workers who sought access to apartments. Tenants’ attempts to get the city to stop the construction failed; city officials said their hands were tied because of Virginia laws that favor property owners.

The tenants also have been fighting rent increases, which they fear will force them out of the high-rises and into a rental market where more than 12,000 affordable apartments have disappeared since 2000. Some, upset that they now must pay utilities in addition to rent, opted for the insecurity of month-to-month agreements rather than signing a long-term lease with a higher rent. They accused Laramar of trying to force them out.

“I realize that the owner has a right to improve the property and raise rents,” said Maurice Barboza, a tenant since 1995 whose rent for an efficiency apartment rose from $795 to $1,096 per month. “My problem is that these buildings are not yet in market-rate condition. They are substandard in the middle of major renovations.”

Boyack acknowledged that there have been rent increases but said the 100 to 150 people most affected had not had increases since 2002, when VDOT froze rents in consideration of the disruption caused by the construction of the adjacent Woodrow Wilson Bridge. Sixty-two percent of tenants renewed their leases in 2013, Boyack said.

“The intent is not to turn this into a new building,” Boyack said in an interview Friday. “It’s more geared toward making it . . . a decent, safe and affordable place to live.”

On Saturday, residents did not believe him.

“This is a sham!” some shouted from the audience. “One lie after another!”