A 68-year-old local woman riding a zip line at Kualoa Ranch Thursday was seriously injured when she crashed into a male rider who was stuck on the line.

The woman is the mother-in-law of a ranch employee and was one of six people out on the trial run of a new course Thursday, which is not yet open to the public, Kualoa Ranch spokeswoman Olena Heu said.

Emergency Medical Services got the call at 2:45 p.m. that two zip-liners collided, and an ambulance was dispatched to the site on the Kaaawa side of the ranch.

The 68-year-old woman was in serious but stable condition when she was transported to an area hospital with a hip injury, Emergency Services Department spokeswoman Shayne Enright said.

Heu said the 2:30 p.m. accident occurred on the fourth stop of a seven-stop course that is miles long and takes two and a half hours to complete.

The ranch had encouraged employees to invite their families to test out the course, and the ranch was in the midst of performing training runs with workers and their families when the collision occurred, she said.

Another guest was on the same section of line, but was stuck on the line because he had not been traveling fast enough to make it to the end, Heu said.

An employee was going out on the line to manually pull him in.

Meanwhile, the batteries on a radio, which the employees used to communicate, were dead, so they used hand signals instead.

They miscommunicated and “inadvertently sent the mother-in-law down while the male was still on the line,” Heu said.

The woman complained of hip pain, so as a precautionary measure, EMS was called, she said.

The fourth section, where the accident occurred, is 1,290 feet long. It is 100 feet off the ground at the highest point, but was 35 feet high in the area of the crash, Heu said.

The company hired to build the course and to perform training is Synergo, which specializes in ropes courses and ziplines, Heu said.

Robert William, a 45-year-old Los Angeles visitor, was at Kualoa Ranch Thursday. 

“We’ve done zip-lining before in Korea,” he said.

“I don’t think it’s going to help the zip-line industry,” he added, referring to the accident.

“It makes you wonder about the regulations,” William said. “It’s probably more insurance and industry-regulated.”

Hawaii does not have any laws regulating zip-line tour companies, though there have been proposals to enact some.

The U.S. Occupational Safety and Health Administration fined the owners and site operators of Piiholo Ranch Zip-Line Course on Maui for the May 6 death of a 29-year-old employee who had fallen 150 feet into a ravine and died. 

OSHA’s investigation found proper safety measures could have prevented Patricia Rabellizsa’s death. The operator’s policy made it optional for employees to wear restraining lanyards connected to their harnesses.

OSHA said the accident happened when Rabellizsa and another worker tried to bring in a customer and the momentum pulled both workers off the platform above a ravine.

In 2011, a Hawaii island zip line tower collapsed because of weak soil, killing worker Ted Callaway, 36, of Lahaina. Another worker was critically injured.