Exterior of the homeless shelter, formerly known as D.C. General Hospital in Washington. (Linda Davidson/The Washington Post)

D.C. officials have halted plans to tear down a building located near the city’s main shelter for homeless families on the D.C. General Hospital campus, after testing showed elevated levels of lead around the soon-to-be-razed structure.

Workers are continuing demolition inside the building, despite complaints by lawmakers and advocates who say Mayor Muriel E. Bowser (D) is endangering children by doing the work before families have been relocated.

The delay in external demolition, announced over the weekend, is the latest snag for Bow­ser’s plan to shut down the dilapidated mega-shelter in October and house families in new facilities spread across the city. After construction delays, the first batch of smaller shelters are to open this fall.

Hillis-Carnes, an engineering firm hired by the city, discovered lead above the acceptable level for schools and day-care centers in five of seven soil samples collected around the perimeter of the vacant building on July 20.

Hillis-Carnes notified the Department of General Services, which manages city real estate projects, officials with the city agency said.

But the city did not warn shelter residents until 15 days later, on Saturday, after additional testing found unacceptable levels of lead in one of seven soil samples taken July 26. That site was reanalyzed days later and did not have elevated levels of lead.

In an interview Monday, DGS Director Greer Gillis said she wanted to understand the full extent of the problem, and how to fix it, before notifying the public.

“Until we knew exactly where [the lead] was located and how deep and how wide it was, we couldn’t finalize an abatement plan,” she said.

Advocates for the homeless say the findings show they were right to be concerned about the demolition occurring while the shelter was still occupied.

“Frankly, I wish we were wrong. What this means is the risk to families can no longer be claimed as conjecture: This is real,” said Aja Taylor, advocacy director for the anti-poverty organization Bread for the City. “The only right thing to do at this point is to delay demolition.”

Last week, after a July 30 anti-demolition protest outside the mayor’s house, Gillis released a statement assuring that demolition was “being done in a slow and systematic way to ensure the safety and health of the remaining D.C. General residents and the greater community.”

The statement did not mention that unacceptable levels of lead had been discovered nearby.

In a report filed July 31, Hillis-Carnes said the lead found in the soil likely came from wooden window frames on the building that is slated for demolition. Ninety percent of those frames have already been removed, the report said.

Lead cleanup work will begin Friday and is expected to last a week, Gillis said. Soil samples from farther from the vacant building, and closer to the shelter building, did not have dangerous levels of lead.

Gillis maintained that demolition could continue safely once the lead decontamination is completed. She said the health of nearby residents was not in danger.

“We are doing above and beyond what we normally do when we do abatements of urban buildings here in D.C.,” Gillis said.

Asked repeatedly why the city couldn’t start razing the hospital campus after homeless families left, Gillis did not provide a clear explanation.

The city owns the land, which is available for development and part of which is included in the District’s bid for Amazon.com’s planned second headquarters, but Gillis said having the land ready for sale wasn’t a factor.

“There’s not a hard-and-fast date we have to complete the demolition,” she said. “Now is a good opportunity for us to be able to do that, as opposed to one big effort where a wrecking ball comes in.”

(Amazon chief executive Jeffrey P. Bezos owns The Washington Post.)

Children exposed to lead can have debilitating long-term problems, including developmental delays, decreased IQ, neurological problems and — when lead levels in the blood are high enough — seizures and coma.

No level of lead in a child’s blood is considered safe, according to the U.S. Centers for Disease Control and Prevention.

Valerie Baron, a staff lawyer at the Natural Resources Defense Council, said that in light of the extreme hazard lead poses, it would make sense to delay razing the D.C. General campus until after families have left.

“Even if the proper protocols are used, there’s still a risk,” Baron said.

Last month, the D.C. Council considered legislation that would halt all demolition at D.C. General until families were relocated.

Instead, lawmakers passed a watered-down version of the bill requiring weekly reporting of lead and asbestos testing results.

Council member Trayon White Sr. (D-Ward 8), who authored that bill, declined to comment on the lead findings when reached by phone Monday.

But council member Elissa Silverman (I-At Large) said the Bowser administration should reconsider its demolition plans.

“I don’t understand what the rush is in demolishing, given there could be a health risk to families, and especially children,” Silverman said. “Why would we put residents’ health at risk — children’s health at risk — if we just need to delay the demolition by a few months?”