The amount of airborne asbestos at Alexandria’s Hunting Point apartments is not enough to harm people who breathe it for weeks or months, a federal study has concluded, but there is not enough data to make long-term predictions.

The Agency for Toxic Substances and Disease Registry, part of the Centers for Disease Control and Prevention, examined dust and air samples that the Environmental Protection Agency collected at the 530-unit towers over the past five months.

Its letter to the EPA this week said that while concentrations of asbestos in the air “do not appear to be high enough to harm the health of people who breathe this air for relatively short periods of time . . . uncertainties described above make it difficult to say there is no long-term risk from exposures to low levels of asbestos that might remain in the building.”

The EPA issued a rare stop-work order on renovations at the apartment complex this month after inspectors discovered asbestos in the floors, doors and windows and found that work crews were not taking legally required precautions. The renovations have been going on since last summer, when a new owner bought the buildings from the Virginia Department of Transportation and began upgrading windows, floors, pipes and other basic infrastructure.

After multiple unresolved complaints from residents to the landlord, the city and the state, a resident called the EPA, which sent in teams of investigators. Renovations are still on hold.

The EPA plans to meet Monday with residents to discuss the results of the sampling and explain its next steps.

Stefanie Ackerman, a Hunting Point resident who has a 3-month-old child, said she feels better after reading the toxic-substances agency’s letter but has “mixed feelings” about the safety of the apartments. Ackerman, a George Washington University law student, is also exploring whether she and her fellow tenants should sue over the asbestos exposure.

The situation should make tenants wary, said Mary Hesdorffer, a nurse practitioner and executive director of the Alexandria-based nonprofit Mesothelioma Applied Research Foundation. Mesothelioma is a form of cancer, most often caused by asbestos, that affects the smooth lining of the chest, lungs, heart and abdomen.

“The real crux of this is there was exposure to asbestos dust, and nobody has been able to settle how much [exposure] is too much,” Hesdorffer said after reviewing the letter. “There may be people who are more sensitive than others. We’re seeing younger and younger children with mesothelioma. . . . There is just no safe level.”

Hesdorffer advised Hunting Point residents to make sure that their medical records reflect that they’ve been exposed to asbestos, whether they fall ill in the near future or not. She added, “If anyone has cancer in the family . . . [they] may want to take even more precautions.”