Shriya Shah-Klorfine climbs an icewall during training. (Courtesy of Bruce Klorfine)

A Nepalese expedition company that guided a Toronto woman who died on Mount Everest allowed her to climb with its less-experienced Sherpas and should have known she would run out of oxygen, an investigation by CBC's the fifth estate has found.

Shriya Shah-Klorfine, 33, was one of six people who died on the mountain on the weekend of May 19, 2012.

The Torontonian had long dreamed of reaching the 8,848-metre summit. With no climbing experience, she paid Utmost Adventure Trekking, a company that she learned of through family in Nepal, almost $40,000 to guide her.

Grayson Schaffer, a writer and editor for Outside Magazine who was at Everest's base camp for the 2012 climbing season, told the fifth estate in a documentary that airs this Friday that few people had heard of Utmost, a startup company that had never guided anyone to the summit.

"You had Sherpas who weren’t actually qualified guides who were guiding a climber who had never climbed before and … putting those two groups together is just a recipe for disaster," Schaffer told the fifth estate.

Utmost took Shah-Klorfine on as a client, despite her inexperience. They planned to teach her everything they thought she needed to know about mountaineering once she arrived at Everest.

"I talked with her and every time she said, ‘I can do it. I can do it. I can do it,' " company manager Riishi Raj Kadel told the fifth estate.

Warned she could die

But in her training, Shah-Klorfine lagged far behind.

"She's slow. Everyone knows she was slow. But she wasn’t sick from altitude. Never any headaches. She continued walking you know," Raj Kadel says.

During her training, Shah-Klorfine had to be taught almost everything, including how to put crampons on her boots.

A string of climbers slowly wind their way up the Lhotse Face. It took Shriya Shah-Klorfine seven hours to climb from Camp 3 up the Lhotse Face, about two hours longer than climbers typically prefer. (Courtesy of Utmost Adventure Trekking)

As the date for her climb approached, however, Utmost Adventure's most senior Sherpa apparently changed his mind about guiding Shah-Klorfine to the summit. He told her she could kill herself and her Sherpas if she attempted to climb Everest, the fifth estate found.

Her husband, Bruce Klorfine, in his first interview since his wife's death, says his wife never told him this, even though they were in frequent contact by phone before her summit attempt.

Klorfine was surprised his wife chose to go ahead with the climb despite the warning — and that the company let her.

But her husband notes she was very determined to climb Everest.

"If she wanted something there was nothing you could say to stop her," he added. "She was very strong-willed, you could say Type A."

Shriya started her push to the summit at 7:30 p.m. on May 18.

The owner of Utmost Adventure Trekking, Ganesh Thakuri, who was climbing the mountain that night and the senior Sherpa had left Shah-Klorfine to climb with two less-experienced Sherpas.

On his way back down from the summit, Thakuri met Shah-Klorfine, still climbing toward the top, but almost out of oxygen.

Thakuri told the fifth estate he tried to convince her to turn around.

"Even if we say you cannot go, you have to go down, strongly. She says like no, I spent money and my goal is to reach to summit. And anyhow I will go. So in this case, we cannot do anything."

She refused to turn around, and Thakuri gave her one last bottle of oxygen and let her keep climbing.

Revelled in the moment

After about 19 hours of climbing, Shah-Klorfine made it to the summit at about 2:20 p.m. on May 19, and spent almost half an hour there revelling in the moment.

Raj Kadel says the Sherpas didn't tell him about her dwindling oxygen supply.

"They just said we're on the way back."

Shah-Klorfine started her descent with the Sherpas, who later kept pushing her along, physically and verbally.

"She could stand only if the two of us held her and that for just a short while. But if she moved her legs, she would fall. It was as if she had been almost paralyzed," one of the Sherpas told the fifth estate.

According to veteran Everest guide Russell Brice of New Zealand, that bottle would probably have lasted about four hours.

But Shah-Klorfine was using a lot more oxygen than other climbers due to the fact that she kept it flowing at a high rate, began using it earlier in her climb than most and spent a longer time on the mountain.

Brice says Shah-Klorfine was given enough oxygen to reach the summit, but not for the return trip.

On her descent, Shah-Klorfine stopped moving and speaking at about 10 p.m. May 19, the Sherpas say. She had been climbing for 27 hours straight when she passed away. Her body was carried back down about 10 days later.

Ten climbers died on Everest during the 2012 climbing season.

Brice, who cancelled his Everest expedition this year, says companies should put saving lives ahead of reaching the summit.

"You know part of the problem over the years is we've become too successful. It looks as though it’s almost automatic that people can get to the summit of the mountain. But it's not true. It can, it can come back and bite you and that’s what it did this year."