LAS VEGAS -- The Friday fire at the Monte Carlo Resort and Casino was most likely caused by flying molten metal from a handheld cutting torch, the Clark County Fire Department announced Thursday.

At the time of the fire, workers on the roof of the hotel-casino were cutting corrugated steel products used for part of a walkway being installed on the interior of the protective wall along the perimeter of the roof, officials said.

“We believe this fire could have been prevented had appropriate steps been taken,” Chief Steve Smith said in a press release. “It appears that no slag mats were used to catch the molten metal, and no fire watch had been posted. Additionally, the contractor responsible for the work on the roof did not obtain the necessary ‘hot works’ permit. We are now reviewing whether to cite the contractor.”

Such citations are by law misdemeanors, punishable by up to a $1,000 fine and/or six months in jail.

County regulations require a contractor to obtain a hot works permit from the fire department when using a torch. A licensed contractor is responsible for knowing what permits are needed for a particular job and obtaining all necessary permits.

The pieces of molten metal, called “slag,” started the fire on the southwest corner of the main façade at the roof line. On-scene construction workers unsuccessfully attempted to extinguish the fire, which spread to the exterior architectural façade of the building. The fire, investigators said, was accidental.

The contractor, Union Erectors Limited Liability Company, had a permit from the county Department of Development Services to install window-washing equipment at the hotel – but no hot works permit. In general, hot works areas should not contain combustibles or should be provided with appropriate shielding to prevent sparks, slag or heat from igniting exposed combustibles.

Also, contractors performing hot work operations are to conduct hot works site inspections to ensure that there are no exposed combustibles on the opposite side of partitions, walls, ceilings and floors.

MGM Mirage, the owner of the Monte Carlo, released the following statement:

“MGM MIRAGE has just learned that the County investigation into the fire at Monte Carlo has confirmed the preliminary results of our third-part forensic expert's investigation that also determined the cause of the fire was related to welding activity on the roof of the hotel.

We have also determined that the property’s maintenance of certain paperwork for this activity did not meet our corporate standards. That situation is being immediately addressed internally and will be reviewed with fire department and county officials as appropriate.

The company looks forward to reviewing the complete results of the official county investigation of the incident.”

The contractors were not available for comment.