Terence M. O'Sullivan, president of the Laborers' International Union of...

Terence M. O'Sullivan, president of the Laborers' International Union of North America, has pushed for oil drilling in the Arctic National Wildlife Refuge, a stance that puts him at odds with others in the Democratic Party. Credit: The Chronicle / Liz Hafalia

Election-time discord has bubbled up between Democratic Party stakeholders, pitting at least one leading environmental advocate against several blue-collar labor unions.

The clashing goals of two prominent individuals in particular reflect the kind of tension that arose when Hillary Clinton’s comments on coal cost her in the May 10 West Virginia primary.

On one side is Thomas Fahr Steyer, 58, a Manhattan-born-and-raised billionaire, former hedge fund manager, and environmentalist who has long fought extending the Keystone XL oil pipeline.

Perhaps the loudest voice on the other side belongs to Terence M. O’Sullivan, 60, president of the Laborers’ International Union of North America, who has pushed for oil drilling in the Arctic National Wildlife Refuge.

Recently the AFL-CIO partnered with Steyer on a new super PAC, For Our Future. Presidents of eight building trade organizations signed a letter to AFL-CIO president Richard Trumka stating serious concerns.

“The AFL-CIO has now officially become infiltrated by financial and political interests that work in direct conflict to many of our members’ — and yes, AFL-CIO dues paying members’ lives,” says the letter, quoted Tuesday in published reports.

O’Sullivan, in a missive of his own, accused the leadership of “an obsession with and a desire to throw open the doors of labor to outside organizations that are completely out of touch” with blue-collar workers’ concerns.

Last week Mario Cilento, president of the New York State AFL-CIO, said in a statement when contacted: “Our first priority is always our affiliated unions.”

“Having said that, we work with outside groups all the time, including advocates for the environment. We may not always agree, but there are many times when we work very well together on issues of shared concern.”

By talking about killing jobs in one industry while ideally producing others to replace them, Clinton drew fire.

In March she said she was the only candidate with a plan for “how to bring economic opportunity using clean, renewable energy as the key into coal country. Because we’re going to put a lot of coal miners and coal companies out of business.”

Jobs-versus-ecology concerns aren’t limited to coal country.

Roger Clayman, executive director of the Long Island Federation of Labor, cited an agreement to support the offshore Deepwater One wind-farm project 30 miles off Montauk as “threading the needle.”

Clayman said the federation has underscored the need for “a just transition” for those with jobs in the industry as it exists now.

The clash also shows how private-sector and public-service unions can find themselves on different pages.

The For Our Future PAC is supported by the American Federation of State, County and Municipal Employees and the American Federation of Teachers. Steyer agreed to match the labor-union donations.

Policy disputes on the Republican side have so dominated the news in recent weeks, it became easy to forget competing interests in the Democratic tent.

Not anymore.