The Atlanta Journal-Constitution’s investigative team has won a third national journalism award for exposing how the business practices of apartment owners have trapped tens of thousands of metro Atlantans in unsafe and unsanitary living conditions.

The AJC series “Dangerous Dwellings,” published in five installments last year, was among the winners of the National Headliner Awards, announced Wednesday. Founded in 1934 by the Press Club of Atlantic City, the annual contest is one of the largest and oldest in the country recognizing journalistic merit in the communications field, with categories for newspaper, photography, online, radio and television reporting. The AJC’s series took first place in the category of investigative reporting in newspapers in top-20 media markets for work done in 2022.

“Dangerous Dwellings” previously won a national award from Investigative Reporters & Editors, which was announced in April. It also received a silver medal in the Bartlett & Steele Awards by The Reynolds Center for Business Journalism at Arizona State University.

“For decades, slumlords have been the targets of investigative journalism. But The Atlanta Journal-Constitution’s journalism on this topic in 2022 was a standout for its depth and reporting,” the judges for the Headliner Awards wrote. “For reporters, it was an uphill battle. They needed to fight to get basic information, such as code enforcement violations, and then build their own database. Most importantly, the project had results: Local governments cracked down on landlords, many of them out-of-state private equity firms.”

Other Headliner Award-winning newspaper entries included coverage of a mass shooting at a Fourth of July parade near Chicago, a series on how the COVID pandemic exposed poor housing conditions in Los Angeles, a narrative on the assassination of Haitian president Jovenel Moïse, and an Oregon newspaper’s investigation into its own racist past. The Best in Show Newspapers award went to AL.com for exposing how a small Alabama town’s police force preyed on residents to drive up revenue, prompting the resignation of the police chief and a state audit.

As a result of “Dangerous Dwellings,” the city of Atlanta promised a crackdown on substandard housing. Other local governments including Gwinnett County, Sandy Springs and Brookhaven moved to strengthen apartment regulations. The Georgia House approved a bill by a unanimous vote which, for the first time, would require Georgia landlords to provide rental units that are “fit for human habitation.” The measure did not come up in the Senate before the General Assembly adjourned, but the bill will be considered again next year.

AJC staff members honored for their work on the project were investigative reporters Alan Judd, Willoughby Mariano and Johnny Edwards. Other key staffers on “Dangerous Dwellings” were managing editor Shawn McIntosh, investigative editor Lois Norder, data analysts Jennifer Peebles and Eric Fan, and presentation specialist Pete Corson.