A kinship exists between Pittsburgh and Harbel, Liberia. When workers on the Firestone rubber tree plantation in the West African nation sought help from American unionists, their brother and sister workers at Firestone plants across the United States, members of the Pittsburgh-based United Steelworkers, stepped forward.

That was three years ago. In August, the Liberian workers, with the aid of money and training from the USW and the AFL-CIO Solidarity Center, signed a historic labor agreement with Firestone. It gives them a 24 percent wage increase retroactive to January 2007, a 20 percent reduction in the number of trees they must tap for latex each day and mechanized transportation to convey latex to weigh stations so workers no longer must walk for miles lugging tremendous loads yoked to their backs.

More than all of that, it gives them dignity.

This story of international union partnership began in 2005 with a letter from 11 Liberian workers from the Firestone Plantation to the AFL-CIO. The federation president, John Sweeney, passed it on to me because the USW represents Firestone workers in the United States.

The letter described unconscionable child labor and environmental law violations at the plantation. I sent the new USW vice president for human affairs, Fred Redmond, to investigate.

He flew to the largest rubber tree farm in the world, with acreage accounting for nearly 4 percent of the entire country, which, by the way, was founded by freed American slaves. On the first day, Firestone officials gave Mr. Redmond the official tour, including their 18-hole golf course, tennis courts and modern two-story brick homes complete with all the normal Western amenities.

On the second day, he slipped onto the plantation unescorted before dawn. There he confirmed what was described in the workers' letter and what was written in a report called, "Firestone: The Mark of Modern Slavery," by a Liberian nonprofit group called the Save My Future Foundation.

The plantation workers live in the same lean-to huts constructed by Harvey Firestone in 1926. Families share outhouses and a community pump. In the dry season, when the pump does not draw water, they drink from creeks and rivers, some of which the Save My Future Foundation says Firestone has polluted.

Bridgestone, the parent company of Firestone, which pocketed a profit of $1.16 billion last year worldwide, paid its 10,300 Liberian rubber workers between $2.65 and $3.38 a day -- if they met the quota of tapping 750 trees, collected the latex in buckets weighing 75 pounds each and carried it for miles on their shoulders to weigh stations. If not, their wages would be halved.

To meet that quota, Mr. Redmond learned, most tappers enlisted their spouses and children as helpers. Children were not on the official payroll, and that is how Firestone would contend that it did not "employ" child labor.

Mr. Redmond also found separate and unequal schools -- those with adequate books and supplies for the children of company managers, and those without for workers' children.

These conditions were held in place for 82 years by a company union for which Firestone hand-picked the officers. This practice, a U.N. investigation found, compromised the union's independence and crippled its ability to advocate for workers.

Guards discovered Mr. Redmond on the plantation and demanded that he leave. But the USW and the AFL-CIO Solidarity Center returned to help the workers.

In January 2006, workers conducted a wildcat strike to demand the right to elect union officers who would represent their interests. We knew they would need help, so our U.S. Firestone workers collected money at their plant gates. Those collection drives, together with support from the AFL-CIO Solidarity Center, paid for food and union training over three years.

The government of Liberia intervened to help settle strikes, with Firestone agreeing over time to improve housing, medical facilities and schools and, eventually, to hold elections.

Over the next two years, workers were killed, beaten and tear-gassed in their struggle to gain the right to elect leaders who truly would represent their interests and improve their lives. The assailants remain unknown and unprosecuted.

The USW and AFL-CIO Solidarity Center stood behind the workers with training and pressure for the government to support them. They were lucky that their uprising occurred simultaneous to election of a reformer president, Ellen Johnson-Sirleaf, and her appointment of a human-rights activist as minister of labor, Samuel Kofi Woods.

In the end, the workers got a contract that means their children can avoid work and go to school. For the first time, they will be permitted to go to high school. For the first time, there will be busing on the 1 million-acre plantation for the workers and their children.

Officers of the union came to the USW convention in Las Vegas in July and thanked us for our help by telling us that if we ever need their support, our brothers and sisters in Liberia will be there for us -- as we will be there for them.