Maybe, someday, union carpenters will be allowed to return to work at trade shows at the Pennsylvania Convention Center.

Or, maybe they won't.

Either way, the leaders of labor unions who work at the Convention Center will be watching. They are exploring a potential positive, yet unintended, consequence of the dispute between the carpenters union and the center. Could their members, the union leaders wonder, wind up qualifying for a state pension?

"A pension is the best thing for a worker," said Michael Barnes, who leads Local 8 of the stagehands union. "The only thing better than having a pension is having two pensions."

The pension question hinges on a hot topic in employment law: joint employment.

Is the Convention Center, and through it the state of Pennsylvania, a joint employer of carpenters, stagehands, electricians, laborers, and others who work, or used to work, at trade shows at the Center? The Convention Center doesn't pay the workers. They get their checks as employees of a private-sector labor broker, Elliott-Lewis Corp, which fills labor requests from the contractors who come in to set up conventions and booths at the Center.

And if the Convention Center is a joint employer, do the workers qualify for state pensions? And if not, then the PLRB doesn't have jurisdiction, because it doesn't decide private-sector cases.

On April 16, 2015, PLRB hearing examiner Jack E. Marino preliminarily denied the Convention Center's request to dismiss the case on jurisdiction. "The undisputed facts … demonstrate that the authority exercises significant control over employees at the center. It may not directly pay employees … but it does exercise significant control," he wrote.

Since 2003, the Convention Center has required all the unions at the center to sign a customer satisfaction agreement that provided wage increases, spelled out work rules, and gave the Center the right to eject any worker for poor conduct.

In May 2014, the carpenters lost their right to work in the building when their leader didn't sign a new version of the customer satisfaction agreement by a quick deadline. The leader later signed, but the carpenters' work had been already distributed to other unions, particularly to stagehands and laborers.

The carpenters filed an unfair practice claim against the Convention Center Authority with the PLRB. The union said the PLRB should hear the case because its caseload involves state entities and the center is a state entity, as well as a joint employer with Elliott-Lewis. The center acknowledged it was a state entity, but disagreed that the PLRB should hear the case, saying Elliott-Lewis, a private-sector company, was the sole employer of the workers.

The first round of PLRB hearings in the case ended Wednesday, with Marino telling lawyers from both sides that he fully expected them to appeal his findings on the facts of the case and also whether the PLRB has jurisdiction based on the joint-employer issue.

Convention Center Authority Chairman Gregory Fox makes his living as a pension lawyer  and, he too, is watching the outcome of the case from that perspective. Fox said it would raise the question for any state agency that hires a vendor with employees to perform functions for the state.

He would not comment on the case itself.

"There is the potential for some wide-ranging impact here," he said. "I think it's an issue that's been thought about, but I don't think it's driving this case."

A spokeswoman from the Pennsylvania State Employees Retirement System said to direct questions to the Convention Center, but sent along a portion of the retirement code that says that state employees qualify for pensions, except "any person paid directly by an entity other than a State Employees Retirement System Employer."

Testifying on behalf of the Convention Center, leaders of the stagehands union, the laborers union and the electricians union all told Marino on Tuesday that there never was a plan to exclude carpenters from the center. But once their work was distributed to the other unions, they would have objected strongly to the carpenters' return.

Even so, if the carpenters convince the PLRB and state courts that the center is a joint employer, it will open a window for the other unions, their leaders say.

"We're investigating," Barnes said. "Right now, our union has an existing pension plan that is contributed to by Elliott-Lewis. Our members will collect that pension. If there is a joint employer, we'll look to see if they are eligible to collect a second pension from the state."

John Dougherty, who leads International Brotherhood of Electrical Workers Local 98, said his union's lawyers are "absolutely" looking into the possibility of applying for state pensions, particularly for a core group of electricians who have worked at the center for years.

Ryan Boyer, who leads the laborers district council and is also an Authority Board member, said the idea of the state being a joint employer seems to be "beyond the pale." He said his union isn't "looking at anything like that," at least not yet. But, he said, "Barnes isn't far off."