LOS ANGELES >> The labor-management standoff that is disrupting billions of dollars of international trade at West Coast seaports now centers on the future of one man who resolves workplace disputes at the ports of Los Angeles and Long Beach.

After nine months of bargaining for a new contract and weeks of partial port shutdowns, dockworkers and their employers disagree on whether they should change the system for arbitrating allegations of work slowdowns, discrimination and other conflicts.

More specifically, their quarrel is focused on the man who since 2002 has arbitrated grievances in Southern California.

Three people with knowledge of the contract talks say negotiators for the dockworkers’ union want arbitrator David Miller out, while the association representing employers will not support changes that would allow his immediate removal.

The people insisted on anonymity because they were not authorized to discuss the negotiations publicly.

Union negotiators believe Miller favors employers in disputes, for example claims that workers are intentionally slowing down cargo movement. In a letter to members last week, the union’s president wrote that negotiators for employers were unwilling to budge because their side benefits from the current system.

Miller told The Associated Press he is aware that he has become the focal point of the closed-door talks but is unsure why. He figures that in the hundreds of decisions he has issued, he upset someone who is now getting back at him.

“I’m bewildered as anybody else on the outside looking in,” Miller said.

U.S. Labor Secretary Thomas Perez entered the standoff on Tuesday in San Francisco, where he settled into his new mission of forging a new contract. Perez does not have legal authority to force an agreement, but outsiders hope he can coax one that would end the protracted troubles.

In a written statement, Perez’s office characterized Tuesday’s meetings with both sides as “positive and productive” and said he stressed the urgency to reach a deal “to prevent further damage to our economy and further pain for American workers and their employers.”

Spokesmen for the International Longshore and Warehouse Union and the Pacific Maritime Association, which represents shipping lines that carry cargo and port terminal operators that handle it once ships dock, declined comment, citing a media blackout.

As negotiations drag on, the consequences of the cargo bottleneck are rippling through the U.S. economy.

The 29 ports on the West Coast handle about $1 trillion worth of goods annually, including Asian imports such as electronics, household goods and clothing as well as U.S. exports such as produce and meat.

Honda Motor Co. is slowing production at six factories in Ohio, Indiana and Canada due to parts shortages. California citrus exporters say exports are half of normal to places such as Korea, Japan and China. Examples from impacts on industries abound.

On Tuesday, 32 massive ocean-going vessels were anchored and awaiting a berth at the twin ports of Los Angeles and Long Beach — the nation’s largest port complex. The scene was similar outside the smaller ports of Oakland, and Seattle and Tacoma in Washington state.

Lines grew notably longer over the holiday weekend, when employers again locked most longshoremen out of work rather than pay enhanced wages.

Employers say dockworkers are intentionally slowing down, an allegation the union denies. On Tuesday, employers hired full work crews for the first time since Friday.

Currently, Miller and three other arbitrators oversee separate areas of the West Coast and are effectively appointed for life. The union wants either side to be able to dismiss an arbitrator when a contract expires, with both sides agreeing on a replacement. Recent deals have lasted six years and the one being negotiated could last five.

The maritime association wants to keep the current system. It has argued that if arbitrators are subject to reappointment they might not rule independently due to worries they might offend one side and jeopardize their future.

It was the union that initially submitted Miller’s candidacy for an arbitrator position. Before his appointment, he had been a member of the local branch which represents clerks in Los Angeles and Long Beach.

Without offering details or naming names, union president Robert McEllrath wrote a letter last week that questioned “retaining arbitrators who have openly engaged in conduct that clearly compromises their impartiality, including the development of close and personal relationships that affect decision-making.”

Miller understood that to be a reference to him, but in the interview with the AP said he has been impartial and believes he rules for the union in most disputes.

“When do we think these so-called crimes were committed that made everybody go so crazy,” he said. “You hear a theory and you hear innuendos. But who, what, where, when? And I don’t think it exists.”

The two sides already have reached tentative agreements on key issues including health benefits and what jobs the union can retain in the future.

Their different wage proposals are not far apart. Under the prior contract, which expired in July, average wages exceed $50 an hour, according to the maritime association. The union says wages are set between $26 to $36 an hour — though many shifts carry a premium over that range.