CityCenter workers are back at work.

At midnight Monday night, workers at CityCenter walked off the job over safety concerns.

Workers for CityCenter went back to work late Tuesday night, while workers for the Cosmopolitan Project returned to the site at 9pm.

Trade Union chiefs and general contractor Perini have come to an agreement.

The company will let an outside party do a work site safety assessment and give workers more safety courses.

Perini released a statement saying that Perini Building Company considers safety its highest priority, and it "maintains its unwavering commitment to the construction industry and to the community to provide safe work sites."

The owner of the site, MGM Mirage, also released a statement saying it will continue to work with the union and contractors to "ensure that safety awareness and individual responsibility are foremost in the minds of every worker on the job site."

Since the groundbreaking at CityCenter, six workers have lost their lives.

Stay tuned to Action News as we monitor developing news around the Valley.