A top union official said he is fed up with ongoing battles over the new arena and the North Shore casino, saying they could jeopardize jobs and give the city a bad name with developers.

"We're sending the wrong message to people. We're putting impediments in front of everyone. You have to fight every step of the way. You get all the permits and you still got to fight. It makes no sense," said Richard Stanizzo, business manager of the Pittsburgh Building and Construction Trades Council.

The council, an umbrella organization representing about 20,000 tradesmen and women, sent a letter Monday to Mayor Luke Ravenstahl, Allegheny County Chief Executive Dan Onorato and Gov. Ed Rendell in support of the $290 million arena construction, which will generate numerous jobs for its members.

"We do not agree with or support any effort to stop this project from moving forward, and any such action puts in jeopardy union jobs and the economic benefit of redevelopment in an area in need of major investment," stated the letter, signed by Mr. Stanizzo.

The correspondence and labor leader's comments came in response to appeals filed last week on two fronts: by the Riverlife Task Force and two others over the size of the 3,800-space parking garage adjacent to the casino and by the One Hill Community Benefits Agreement Coalition over the arena project.

They are challenging city planning commission approvals last month involving the casino design, including the garage, and the master plan for the Penguins' new home.

While the arena appeal does not seek to block construction, Carl Redwood, chair of the One Hill Community Benefits Agreement Coalition, has said the group would do everything in its power to stop the project if there is no community agreement.

Riverlife has asked the state Supreme Court to reverse or vacate the planning commission approval and stop building permits from being issued for the garage, or to appoint a special master to determine whether the design complies with zoning requirements.

Mr. Stanizzo said the continuing legal fighting "definitely is sending the wrong message" to developers thinking about coming to the area.

"All things being equal, if you're going to have this roadblock put up in front of developers and they have the option of going somewhere else, they're going to go somewhere else," he said.

Responding to Mr. Stanizzo's letter, Penguins President David Morehouse, in the team's first public comments on the One Hill appeal, described the litigation as "counterproductive."

"There's a point where cooperation becomes obstruction and that point is reached when a group starts stating publicly that it's going to do everything it can to stop the project," he said.

Mr. Redwood said One Hill is not trying to be obstructionist in its drive for a community benefits agreement. He said there is no reason an agreement should inhibit development.

"We're just trying to come up with a situation that's beneficial for everybody involved and it can be done," he said. "There has to be a will to come up with an agreement that's beneficial for all involved."

Lisa Schroeder, Riverlife executive director, said the group has no interest in delaying the project and doesn't believe the appeal will hold up construction of the casino itself.

She said the litigation was a "reluctant action" aimed at addressing alleged zoning code violations that could have long-term negative ramifications for riverfront development.

As for the building and construction trades letter on the arena, Mr. Onorato "completely agrees with Rich Stanizzo that the project should not be delayed," spokesman Kevin Evanto said.

Mr. Ravenstahl could not be reached for comment.

The arena is scheduled to open in time for the 2010-11 Penguins season. The casino is expected to open in May 2009.