Calls to Ironworkers Local 433 offices in Las Vegas and City of Industry, Calif., were not returned.

The builder said it is working with its subcontractors to identify the other individuals who were observed drinking alcohol and then entering the CityCenter work site.

"This matter has been given the highest priority and we will terminate all individuals who can be identified," Doug Mure, Perini's vice president of human resources and risk management, said in a statement Thursday. "We will continue to take a zero tolerance approach to this type of behavior."

Over a six-week period, 10 workers were observed at various bars across from MGM Mirage's $9.2 billion development. On Tuesday, photos of eight of the men were shown to Perini and MGM Mirage officials.

Steve Ross, secretary-treasurer of the Southern Nevada Building and Construction Trades Council, said each member union has different disciplinary policies.

He said it is very likely that the three men who were fired will be disciplined by the union, most probably starting with having to appear before the union's executive board.

Some unions have strict rules that could include expelling a member, which would prevent the workers from obtaining other union jobs.

Ross was not aware if the Ironworkers Local 433's rules would include expulsion.

He said the unions take a proactive approach to drug and alcohol abuse. When a member is found to have a drug problem, the union tries to get the person help.

Perini officials could not be reached for further comment after Thursday's announcement.

On Tuesday, though, Pat Hubbs, executive vice president of field operations for Perini Building Co., said any employee fired from one project can't work on any company project for at least a year.

Fired workers are banned from MGM Mirage projects permanently, he said.

Hubbs said he was certain that the type of activity observed by the Review-Journal was not common among its workers. He said 99.9 percent of the 7,700 workers at CityCenter are not engaging in behavior depicted in the photos.

However, he said the union and contractors need to discuss what they can do to stop the few workers who are violating rules prohibiting anyone who has been drinking from entering the work site.

One possibility is to monitor bars near to the Strip work site, Hubbs said.

"Do I need to have guys out on the bars on the Strip watching for that," Hubbs said. "It's something we need to look at. If, literally, I've got to get guys at least within the vicinity, certainly these guys will get wise to that and they're just going to go someplace we're not."

Still, Perini Building Corp. Chairman and CEO Craig Shaw agreed Tuesday that, "based on what you've shown us, we have no choice but to do it (monitor the bars)."

Ross said the 17 labor union affiliates of the building trades council, including Ironworkers Local 433, have long recognized alcohol abuse is a problem on construction sites and have addressed the issue.

"They have instituted in their collective bargaining agreements with their employers drug and alcohol policies both the employer and the union agree to," Ross said.

Nevada OSHA officials wouldn't comment on the firings. The agency has no regulations prohibiting drug or alcohol use by construction workers, saying it is an issue between employers and employees.

Contact reporter Arnold M. Knightly at aknightly@reviewjournal.com or 702-477-3893.