A construction worker in the Stanford Research Park was injured Wednesday morning after falling 25 feet down an elevator shaft, the Palo Alto Fire Department said.

The fire department responded to a call at 8:43 a.m. and found that a 46-year-old man had plunged through an opening in the second-story floor at 3401 Hillview Ave., the site of the company VMware.

Paramedics treated the patient for his injuries, and he was "prepared for removal from the shaft," Battalion Chief Doug Conn said. The man was transported to Stanford University Hospital for treatment.

The injured worker is an employee of Swinerton Builders, a construction company working on the site, said Patricia Ortiz, spokeswoman for the California Division of Occupational Safety and Health (Cal/OSHA).

The construction company called the agency to report the accident, saying that the worker was found on the floor, she said. Cal/OSHA sent an investigator out to the scene.

On Thursday a spokesperson for Swinerton said the employee is stable and in intensive care. His doctors are continuing to evaluate his progress and his family is with him.

"Our team has remained close to provide support to the family and aid in the investigation of what happened. Safety is our number one priority and when something like this happens we want to know why," said Brenda Reimche, vice president and director of human resources for Swinerton Incorporated.

"Our investigation of this incident is ongoing and when more facts are known we will make the information available."

The response included Palo Alto Fire engines 5, 8, Rescue 2, a Confined Space/Rescue trailer, Truck 6, medics, the battalion chief and the Palo Alto Police Department.