LAS VEGAS — Construction workers building a massive casino complex on the Las Vegas Strip expected to return to work late Tuesday after a one-day walkout over safety concerns at the site where six workers have died since 2006.

The general contractor of MGM Mirage Inc.'s CityCenter project will arrange for worker safety training and will allow union and business leaders full access to the site at all times, union officials said.

"Something had to be done," said Steve Ross, secretary treasurer of the Southern Nevada Building and Construction Trades Council. Ross said the council negotiated for several hours with general contractor Perini Building Co. before reaching a deal. A safety evaluation of the 66-acre job site would be scheduled by Wednesday, he said.

Perini said in a statement that safety training previously provided only to supervisors would be given to all trade workers. The company headquartered in Framingham, Mass., said it was committed to collaborating with the building trades council on safety.

"We have been informed of today's agreement between Perini and the building trades," MGM Mirage spokesman Alan Feldman said. "We will continue to insist that Perini, its subcontractors and the unions work together to ensure that safety awareness and individual responsibility is foremost in the minds of every worker every day on the job site."

Tate McGinty, president of the local plumbers and pipe fitters union, said that while the agreement would improve working conditions on the complex that's expected to include six high-rise towers, the change would be a slow process and danger would remain as workers hustle to meet a planned opening in late 2009.

"They need to slow down a little bit," McGinty said.

Talks broke down Monday night, and most workers walked out at midnight, Ross said.

"We felt it just wasn't getting to the level it needed to be," he said.

Work was halted as the various building trades honored the picket line at the $9.2 billion complex, which company officials have called the most expensive private commercial development in U.S. history.

McGinty told a handful of workers just before 3 p.m. that a deal had been reached and workers were getting what they wanted.

"We're going back to work tonight," McGinty said to applauding workers who had spent the day picketing in near 100-degree heat in front of the site chanting "No more deaths" as tourists walked by.

The latest death came Saturday when a 39-year-old crane maintenance worker was crushed between the track of a construction crane and its counterweight system, authorities said.

"A lot of people have died — too many," said Paul Jones, 47, an electrician walking the picket line near the construction offices at the back of the nearby New York-New York Hotel and Casino.

"They need to tighten safety up," Jones said.

Other picketing workers said they were asked by union officials not to discuss the strike because they did not have the most recent information on negotiations.

Ross told reporters at a midday news conference that the union was not looking to create a media spectacle, while standing on the median of Las Vegas Boulevard, with the site and workers picketing in the background. Minutes earlier, workers from the back of the site moved to the front, saying they were asked to come forward by union leaders.

The protest came after a series of stories in the Las Vegas Sun newspaper that questioned whether enough action had been taken by unions and the Nevada Occupational Health and Safety Administration.

When asked why workers walked out after the sixth death instead of earlier, Ross said that the sides had been in talks with Perini and MGM Mirage on the issue for some time.

CityCenter is expected to open in 2009 with a 4,000-room hotel-casino, condominiums, boutique hotels and a retail, dining and entertainment complex.

Dubai World, the investment arm of the Persian Gulf state of Dubai, spent almost $5 billion to buy half ownership in CityCenter and acquire 9.4 percent of MGM Mirage.