For the second time in less than a week, Hoover Dam has halted tourist access as federal maintenance crews work to resolve an equipment issue with the facility’s 150-ton cableway system.

The latest shutdown follows a separate closure on July 27, when emergency road repairs forced officials to block public road access through the site, as reported by NBC affiliate KSNV.

According to a press release from the Bureau of Reclamation, the current closure was triggered during routine maintenance when the facility’s cableway carriage “moved unexpectedly and placed additional stress on system components.”

“Hoover Dam remains temporarily closed to all visitors while maintenance crews address an equipment issue involving the facility’s cableway system,” the bureau said in a statement. “The dam and powerplant continue to operate normally.”

A contractor was scheduled to arrive Wednesday to evaluate the equipment and assist workers, ABC affiliate KTNV reported. Federal officials said visitor access would not resume until that assessment was complete.

“Until the contractor completes its evaluation and safely repositions the cableway carriage, Reclamation cannot estimate when visitor access will resume,” the news release stated.

Genevieve Johnson, acting regional director for Reclamation’s Lower Colorado Basin, said that the structure itself remained secure and fully operational.

“We appreciate the public's patience and understanding while our teams work through this situation,” Johnson said in a statement. “Safety remains our top priority. While visitor access is temporarily paused, Hoover Dam and the powerplant are operating normally, and there is no risk to the facility.”

The cableway system, located near the parking garage above the main access road, is used to transfer heavy equipment and materials across the Colorado River between the Nevada and Arizona sides of the power plant. The Bureau of Reclamation noted that safe access remained available for employees and contractors, allowing regular operation and routine maintenance to proceed uninterrupted.

The sudden closure left tourists turned away at security checkpoints near the facility, located in Black Canyon about 35 miles from the Las Vegas Strip.

Standing 726 feet tall, the concrete landmark was built between 1931 and 1936 at a construction cost of $49 million — equivalent to around $165 million today including the power plant and infrastructure. The facility generates an average of four billion kilowatt-hours of hydroelectric power annually, serving more than 1.3 million people across Nevada, Arizona and California.

A flashing electronic sign at a roundabout near the entrance read “Hoover Dam is closed,” according to the Las Vegas Review-Journal. Security personnel standing outside the checkpoint instructed approaching drivers, including travelers who had driven from eastern Canada, to turn around.

The Independent has contacted the Bureau of Reclamation for comment.