DENVER -- A major safety switch was missing from an escalator that malfunctioned at Coors Field over the summer in an accident that injured dozens of baseball fans, city safety inspectors said Tuesday.

A five-month investigation showed the escalator's controller was missing the key switch when the accident occurred July 2. City inspectors said the switch would have prevented the escalator from hurtling out of control.

"The overspeed board wasn't there to detect the problem. We don't know when it was removed," said Julius Zsako, spokesman for the city Community Planning and Development Office. He said the circuit board was there when the escalator was originally certified, and contractors said they inspected it in March.

Mark Spencer, a spokesman for Kone Inc., which maintained the escalators at Coors Field, said the company is reviewing the report.

The company performed its own review of the accident and issued a report that blamed overcrowding and a misconnected wire for the accident.

According to the city's investigation, a device called the Nordic Soft Start, which is designed to slowly bring an escalator up to speed, malfunctioned, disrupting the braking ability of the motors and allowing them to free wheel.

Inspectors said the overspeed board could have caught the malfunction and shut the escalator down.

The Colorado Rockies organization issued a statement Tuesday on the announcement:

"The Rockies regret that this unfortunate accident occurred. We are confident that the thorough inspection of the involved escalator and all other escalators at Coors Field will allow us to open the escalators for the public next season with no reservations about their safety. The controls for the involved escalator have been entirely replaced and upgraded, so the situation that caused the accident on July 2 can no longer be a problem. The controls for the six additional escalators at Coors Field have been carefully inspected and any necessary adjustments have been made."

Since the accident, the Colorado Rockies and Kone have spent thousands of dollars to help injured fans.

The Rockies and Kone agreed to split the cost of medical bills, lost wages, child-care fees and other costs without admitting any responsibility.