The significance of the issue is raised because of the 12 construction-related deaths that have occurred at Strip construction sites in the past 18 months, but the Clark County coroner's office and the Nevada Office of Safety and Health Administration refused to say whether any of the deaths were linked to alcohol or drug use, citing privacy concerns.

The Review-Journal began investigating the matter after receiving letters to the editor reporting that construction workers were seen drinking near the job site, which employs about 7,700 workers operating shifts around the clock.

One letter, from a tourist from the East Coast, said he, his wife and a couple of friends observed construction workers drinking at the bar outside the Monte Carlo sports book in May.

The tourist, who asked that his name be withheld because he is a regular visitor to the city, said three to seven workers were at the bar early each morning during his five-day stay, drinking and talking about the work day ahead.

"It was very obvious these guys were on a first-name basis with the bartenders," he said on the phone. He described the workers' clothes as clean, suggesting they had not been to the construction site yet.

Officials from Perini Building Co., the project's general contractor, on Tuesday expressed shock after being shown photographs and video of some of the workers observed by the Review-Journal. A total of 10 workers were seen drinking, and six of them were photographed walking onto the job site.

"It's real simple: We have a zero tolerance policy," said Pat Hubbs, executive vice president of field operations for Perini. "If they consume any alcohol and go on site, it's grounds for termination."

Hubbs called the workers' actions intolerable and emphasized that anyone entering the job site after consuming alcohol -- even if they are just walking through the job site to get to their cars -- is in violation of policies set by the construction company, its subcontractors and the unions.

While acknowledging that "this type of behavior has been encountered on our Las Vegas construction projects in the past," Perini said in a statement Tuesday that it is taking the newspaper's "allegations seriously" and will investigate the matter.

"We rely on trades to provide us with responsible, well-trained professionals. ... If we determine any of our policies were violated, we will take immediate and appropriate action," the statement read.

The Review-Journal did not approach or attempt to contact the workers involved.

Perini met with trade subcontractors Wednesday in an effort to identify and investigate the actions of individuals seen in the photographs.

"We have secured the full support of the unions in assisting us in this process and expected termination of the individuals who can be identified," Doug Mure, Perini Corp.'s vice president of human resources and risk management, said in a statement Wednesday.

Also present when the Review-Journal presented the photos and its findings Tuesday was Perini Chairman and CEO Craig Shaw and a representative from MGM Mirage. Representatives from the unions working on the project were not present Tuesday but were told about the findings by the newspaper.

In a statement released late Tuesday, MGM Mirage said it "remains confident in Perini Building Company's ability to operate a safe and professional work site, enforce workplace regulations and take prompt disciplinary action when appropriate."

"Perini senior management is investigating the allegations raised by the Review-Journal's report," Gordon Absher, MGM Mirage vice president of public affairs, said. "We expect their efforts will be met with cooperation from every union and subcontractor working at CityCenter."

Other than being terminated by a company or its subcontractors, there are apparently no government regulatory prohibitions against workers showing up at a construction site intoxicated, according to safety and police officials.

Because the construction sites are private property, Las Vegas Metropolitan Police Department spokesman Bill Castle said, DUI laws would not apply unless an intoxicated worker were to drive a vehicle or piece of construction equipment off the site.

Federal safety regulations do not directly address the issue either. Federal OSHA spokesman Roger Gayman said there are no rules prohibiting construction workers from drinking, although an employer could be cited for safety violations under OSHA's general duty clause if certain criteria are met.

The general duty clause requires employers to keep a work site free of "hazards" that could cause an injury or death if there is any feasible means to remove the threat.

A spokeswoman for Nevada OSHA, which has come under criticism by union leaders for not properly enforcing safety regulations at CityCenter and other Strip job sites, said the agency also has no regulations regarding workers consuming drugs or alcohol.

It is an "issue between the employer and employee," department spokeswoman Elisabeth Shurtleff said in an e-mail.

"If an (Nevada) OSHA inspector had a suspicion that an employee was under the influence, they would notify the employer, particularly if the employee were operating equipment."

That's not very reassuring to the Nevada Building and Construction Trades Council, which has accused the state agency of not exercising proper oversight and enforcement at local construction sites.

"Our position with OSHA has been that we just haven't seen the type of attentiveness that we think this body needs to have," trade council spokesman Steve Redlinger said.

"This is potentially, obviously very dangerous behavior, which has ramifications of hurting other people on the job site that have nothing to do with it except (they are) coming to work, trying to make an honest living playing by the rules," he said of the possibility that construction workers who have been drinking are on the job site.

Managers of the project need to take action "before anyone gets hurt," the union official said.

"If this behavior is as you explain it to me, it is unacceptable," Redlinger said. "These are issues that are handled in collective bargaining agreements with the employers. (These) actions are unacceptable and can't be tolerated."

The construction companies, however, don't have a free hand.

Perini's Shaw noted that although the contractors have policies in place to take action against workers if they have reason to suspect someone has been drinking -- say they smell alcohol on his breath -- they don't have the authority to randomly test construction workers for alcohol or drug use.

The contractors do test workers who have been involved in a workplace accident.

National statistics show that alcohol and drug use are major factors in construction site accidents.

Alcohol, drugs or both were present in 19 percent of all workplace fatalities, according to a 1998 study of toxicology reports of work-related injuries conducted by the Bureau of Labor Statistics. Of the 593 toxicology reports submitted by 39 states including Nevada, alcohol was identified in 284 cases.

The Clark County Coroner's Office denied a request by the Review-Journal for the toxicology reports of the 12 construction workers who died on Strip job sites since December 2006, citing the "confidentiality of medical information contained in such reports."

The Nevada OSHA also cited confidentiality in refusing to reveal whether initial incident reports indicated whether drugs or alcohol were involved in any of the accidents, Shurtleff said.

Safety issues at the Strip construction sites have been a major topic for union, safety, government and business officials for the past several months.

The Nevada Building and Construction Trades Council led 17 affiliated unions out on a 24-hour strike of the CityCenter and nearby Cosmopolitan projects in June after negotiations on safety issues broke down between the unions, MGM Mirage and Perini.

The dispute was resolved the next day when Perini agreed to several of the unions' demands, including conducting a safety assessment of the job site and allowing union and safety officials full access to the sites.

The string of accidents and fatalities, including several construction crane accidents, also led government officials to set up a task force to take a look at what government, construction and union officials could be doing to improve safety at construction sites.

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