Arguing that construction workers on public-private partnership projects should not be relegated to the status of “working poor,” Miami-Dade County commissioners on Tuesday approved a requirement that private buildings constructed on county-owned land must pay their construction workers a “responsible” wage.

The legislation, sponsored by Commissioner Sally Heyman, is similar to existing living-wage laws that govern payments to various service workers who are paid with county dollars.

Until now, however, wages for construction workers working on county land were only scrutinized if the workers were building a public building, such as an office for a county agency. In recent years, private developers of affordable housing and other projects increasingly requested county land to build upon — if the county could be persuaded to donate the land or sell it cheaply, the developer benefitted from lower land acquisition costs.

Going forward, such deals will have to guarantee that construction workers benefit through solid wages. Commissioners approved the change by an 8-2 vote, despite the objections of the Associated Builders and Contractors trade group, which argued that the change would inflate construction costs.

“Our living-wage rates are some of the highest in the country,” said Carlos Carrillo, the trade group’s regional vice president. Carrillo said construction costs could rise as much as 30 percent because of the new wage requirements.

Concerns were also raised by Miguel Southwell, the deputy aviation director of business retention and development at Miami International Airport. Southwell said local airlines were skittish about the new rules, which could affect airport projects such as building a new airline hangar on county land.

Representatives of construction workers, however, countered by citing research that higher-paid workers demonstrate greater productivity, and can therefore complete projects on the same budget, despite being paid more.

Bill Riley, business manager for the International Brotherhood of Electrical Workers, said paying workers a more-generous salary had a direct effect on building quality, leading to projects that are “built to last.”

“The policy is simple,” Riley said. “If a private developer wants to build a project on county-owned land, land that is owned by the taxpayers of Miami-Dade County...the workers earn a responsible wage.”

The definition of a responsible wage will vary by job title, and will be based on a combination of hourly wages as well as the value of any employee benefits — such as health insurance — that are being provided.

Commissioners, in approving the new law, said that even if construction costs increase slightly on these projects, that extra money will come from developers’ profit margins, and not from taxpayers.

“We need to treat our labor force properly,” Commissioner Jean Monestime said.

•  In other action, commissioners on Tuesday unanimously approved a ban on synthetic products that imitate the effects of illicit drugs such as stimulants or marijuana. The now-banned substances include synthetic stimulants known as “bath salts” that can prompt erratic behavior in users.