OAKLAND — The A’s breezed through the first step allowing them to study building a waterfront ballpark at Howard Terminal. On to the hard part.

Port of Oakland commissioners on Thursday voted 6-0, with one member absent, to enter into exclusive negotiations with the A’s — a yearlong adventure where the only guarantee right now is the two sides will talk.

A’s President Dave Kaval said he was encouraged by the unanimous vote and afterward did not seem too worried by port union workers’ concerns that a stadium could take away jobs and maritime activity. Kaval said he expects to have those discussions during the one-year deal, known as an exclusive negotiating agreement.

“For us, this is an important first step,” Kaval said outside the port commission board room in Jack London Square.

The A’s also expect to enter into the same agreement with the city of Oakland and Alameda County to study the Coliseum, part of Kaval’s “parallel paths” approach. After being shut out of building near Laney College, A’s management said the two remaining options maximize chances of staying in Oakland, as promised.

Oakland City Council needs to approve the Coliseum study.

Under the one-year agreement, the A’s pay the port $100,000 as they study economic feasibility and environmental, transportation and accessibility issues. The 50-acre Howard Terminal, located west of Jack London Square, is cut off by train tracks and is next to large industrial companies. The Coliseum, however, does not need environmental reports.

Several members and representatives of longshoremen, maritime and other port unions oppose a Howard Terminal ballpark, arguing it would mean the loss of 3,000 employees at companies that are current tenants and a training center that is vital in the event of an earthquake. The center is a backup to a dispatch center at Pier 39 in San Francisco, one speaker said.

Robert Carr, a member of the San Francisco Bar Pilots, said ballpark lights would be at eye level for maritime pilots. “Those lights would be blinding,” blocking pilots’ view of hazards, Carr said.

Supporters of the stadium at Thursday’s meeting included Jack London Square merchants who want more foot traffic, Rob Stoker of the Alameda County Building and Trades Council and Oakland Chamber of Commerce CEO Barbara Leslie.

Michael Carilli of The Port Workspaces, which has two buildings in the neighborhood, said it would be too expensive to dredge the estuary. A shallow berth depth and larger container vessels have made it difficult to operate the site as a container terminal, port officials have said.

“We need to bring pedestrian in to the life of the city, so it is breathing,” the developer said.

The exclusive negotiating agreement is the second time a group has studied building a stadium at Howard Terminal. In 2014, an effort led by a team of Oakland businessmen, the Oakland Waterfront Ballpark, was rejected by former A’s co-owner Lew Wolff, who said the waterfront plan was not feasible.

The A’s expect to make a decision on where to build by the end of the year.