GENEVA (AP) — The International Labor Organization on Tuesday welcomed a global agreement to combat the worst forms of child labor as the first time all of its member states have ratified a convention — in a process that lasted 21 years.

The 101-year-old United Nations agency that brings together governments, business and workers groups says ratification formalized Tuesday by Pacific archipelago Tonga means all 187 members have ratified the convention. It was the fastest ratification of a convention at ILO.

ILO director-general Guy Ryder called so-called “Convention 182” a “historic first” that showcases a global commitment to root out forms of child labor including slavery, sexual exploitation, the use of children in armed combat, or other “illicit or hazardous work” — such as prostitution, drug trafficking or pornography.

Such forms of child labor “have no place in our society,” he added.

The Geneva-based agency estimates 152 million children are involved in labor, with more than two-thirds of the work linked to agriculture.

The ILO’s conference adopted the convention 21 years ago, and the incidence of child labor and its worst forms declined by nearly 40 percent over a subsequent 16-year span as countries increasingly ratified it, the organization said.