Mystic — Mystic Seaport United, the group of museum employees working to form a union, filed an unfair labor practice charge against museum management Wednesday with the National Labor Relations Board.

The board will now investigate the charge, determine if it is true, and if it is, order a remedy.

Eric Bailey, a spokesman for AFT Connecticut, which is helping the workers organize, said it is illegal for Seaport administrators to make workers feel as if they are being watched, harass or interrogate workers about their decision to form a union, or allow anti-union workers to advocate their opinions at work while denying that same opportunity to pro-union workers.

Asked for specific example of alleged illegal activities by Seaport management, Bailey said workers have reported that managers have been sitting in break rooms at all times to make workers feel as if they are being watched and cannot discuss their union efforts. He said anti-union employees are being allowed to talk openly about the process and distribute literature while pro-union employees cannot.

"For union campaigns, this is nothing new. We see this so many times in campaigns," Bailey said. "The law is the law for a reason. We take this very seriously. The employees are granted the right to organize without intimidation or retaliation."

Bailey said pro-union workers are still meeting and signing union cards. In addition, he said the union now plans to talk to seasonal workers who are starting to arrive for work about joining the union.

Union supporters have said they started the effort because they felt that management does not listen to their suggestions or work with them to meet the museum's mission. They said the museum had laid off employees, cut benefits, awarded occasional but small raises, increased insurance premiums and enacted a six-week closure this winter without asking employees for suggestions or alternatives.

Bailey said many of the museum's 200 full-time workers have signed cards saying they want a union. If 30 percent of employees sign cards, a vote will be held. If a majority of those voting support a union, one will be formed.

"It will happen. It's just a matter of time. A month after (we submit the cards), they'll have a vote and have their union," Bailey said.

Seaport spokesman Dan McFadden said the NLRB notified the museum Wednesday that the charge had been filed. But he said he could not comment about the specifics because the NLRB has not forwarded any details yet to the museum.

"We've been careful to instruct and train our supervisors about how they need to communicate with our employees in this situation. We're confident we have not done anything wrong," McFadden said.

j.wojtas@theday.com