Members of the green-building community are mourning the deaths of two influential and trailblazing architects.

Gail Lindsey, FAIA, founder of the Wake Forest, North Carolina-environmental consulting firm Design Harmony, died February 2 of complications from liver cancer. She was 54.

Greg Franta FAIA, principal architect and senior vice president of the Rocky Mountain Institute’s Built Environment Team, based in Boulder, Colorado, died in a single-car accident on a highway south of Boulder. Franta, 58, had been missing since February 9. His car and body were discovered at the bottom of a ravine on March 10.

Although they lived in different parts of the country, Lindsey and Franta often worked together on sustainability projects, and they sometimes collaborated at workshops and conferences. Both helped develop the U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system, and both were founding members of the American Institute of Architect’s Committee on the Environment. Lindsey and Franta also participated in the Greening of the White House energy efficiency project in 1993.

Lindsey made her mark as a passionate advocate for sustainable design. She was among the first LEED trainers, and she helped create the AIA’s Top Ten Green Projects program. In addition to the White House greening project, she had done similar consulting work with the Pentagon, the National Park Service, and the General Services Administration. Last year, she won the AIA North Carolina’s Gold Medal Award. She had recently co-founded, with Bill Reed AIA, Delving Deeper, a workshop program that aims to apply sustainable design principles to personal growth.

AIA President Marvin Malecha, FAIA, dean of the College of Design at North Carolina State University, remembers Lindsey as a “teacher of teachers” within the green-building profession. “She taught a lot of people about doing the right thing,” he says. “Her message was basically that we need to be an integral part of the environment, not apart from it.”

Franta was considered a pioneer in the world of environmentally sustainable architecture. From 1981 to 2005, he was the principal of Boulder-based ENSAR Group, an architectural and sustainable design firm. ENSAR merged with the nonprofit Rocky Mountain Institute, co-founded by energy guru Amory Lovins, and became RMI’s Built Environment Team. In 1998, Franta was named AIA’s Colorado Architect of the Year. At the time of his death, he was working on a book about green building practices, tentatively titled, Cooler Buildings for a Cooler Planet.

Victor Olgyay, principal of the Built Environment Team, recalls working with Franta at ENSAR, a small firm with perennial cash-flow problems. “Someone from Texas called and asked us if we could design a police station with the lowest LEED rating for the least amount of money,” Olgyay says. “Greg said, ‘Yeah, we can do that.’ I said, ‘Greg, why would we do a project like that?’ And his attitude was: this is a chance to save energy. So we did it, and in the end, the building got a silver LEED certification, and it ended up saving a heck of a lot of energy.” Olgyay adds: “I think that sums up Greg’s attitude in general. He would often see the potential where other people didn’t.”

Consultant Cara Taverna Carmichael, who worked with Franta at ENSAR and moved with him to RMI, says he was an inspirational leader with a magnetic personality. “Greg’s death leaves a big void at RMI,” she says, “but we’re all trying to encompass a little bit of what he stood for, and perhaps collectively we can help maintain his vision.”