Nancy Thonen paired engineering expertise with business skills — an approach reflected in our new IBE program

By the time Nancy Thonen (ChemEngr’88) became the first female refinery manager of the Suncor plant in Commerce City, Colorado, she was used to being the only woman in the room.

“A boss once asked if it bothered me,” Thonen recalls. “I told him, ‘That’s all I know.’ There just weren’t many of us, so it became normal.”

Thonen first noticed the imbalance as an undergraduate at ̽����Ƶ in the mid-1980s, estimating women made up about 10% of her chemical engineering class. Engineering “felt like the natural path” after growing up with a civil engineer father, but it was a pair of teachers — one in high school and one at CU — who convinced her to pursue chemical engineering.

“I had this incredible high school teacher who made chemistry fun and exciting,” she said, noting this teacher also taught STEM educator and TV host Steve Spangler. At CU, now-emeritus professor William Krantz taught her “how to use distillation in real life, working in the industry. That resonated with me because I wasn’t interested in graduate school — at least not in engineering.”

Breaking into the field

Thonen spent nearly two decades in the oil and gas industry before returning to school for an Executive MBA at the University of Denver. During those years, she worked “upstream” managing oil-producing fields and then “downstream,” becoming the first woman at Amoco assigned to a fluid catalytic cracking unit — a “cat cracker” that converts heavy hydrocarbons into gasoline and diesel. She later managed the Suncor refinery in Commerce City.

“I was the first female refinery manager at that facility, and it was the hardest job I’ve ever had,” she said. “There’s constant pressure to control costs and stay profitable, but safety is always the foundation. I never wanted to face a family after a serious injury, and I’m proud I never had a fatality on my watch.”

Discovering the business side

Talking daily with operators, mechanics and staff across the refinery sparked her interest in the business side of engineering. She moved into a business development role that offered the flexibility to earn an EMBA while working full time.

“My MBA opened my eyes to different ways of doing things — not just the engineering logic approach,” Thonen says. “It helped me better understand what colleagues were trying to tell me.”

Soon, ̽����Ƶ students with similar interests will be able to pursue the Bachelor of Science in integrated business and engineering (IBE), which blends technical training with business fundamentals.

“We’ve listened when employers tell us they need engineers who pair strong technical skills with real business insight,” said Kurt Maute, associate dean for undergraduate education in the College of Engineering and Applied Science. “The integrated business and engineering degree gives students a competitive edge, combining rigorous mathematical and engineering training with an understanding of business processes and strategies.”

Closing the gap

Thonen retired in 2021 after more than three decades in the industry. While men still outnumber women in engineering, CU Engineering is closing the gap — the fall 2025 first-year class was nearly 31% women, up 17 percentage points from two decades ago.

“I always tell women: if you’re accepted into the engineering program, you belong there,” Thonen said. “Don’t ever doubt that. The hardest climbs lead to the best views.”