Maclay Reed Hyde, a groundbreaking environmental law attorney and a passionate real estate developer of polluted, often discarded, brownfield sites, died March 8 of complications from chronic lymphocytic leukemia. He was 78.

Hyde was a pioneer in a soft-spoken way, exuding calm and quietude whether engrossed in a monumental legal battle such as the landmark Reserve Mining case, or piecing together a complicated real estate development deal.

"He always had a really balanced perspective, and he was universally respected and revered," said Martha Faust, executive director of Minnesota Brownfields, a nonprofit organization. "When he spoke, people would lean in."

Born in Chicago and raised in Minnesota, Hyde honed his leadership skills early on as a student government leader and star athlete at the Blake School. His athletic streak continued at Harvard University, where he was an All-America lacrosse player.

In 1958, he began his legal training, first at Columbia University, then finishing at the University of Minnesota Law School. He commenced his professional career as an attorney at Larson, Loevenger, Lindquist, Freeman and Fraser (now Lindquist & Vennum), where he remained until 1980.

While there, his career took a prescient turn in the early 1970s, when he represented the Reserve Mining Co., a Silver Bay firm that had been sued for dumping waste into Lake Superior. The U.S. Environmental Protection Agency was in its infancy, and the Reserve Mining case was the first major state and federal environmental case to gain national attention. It helped to establish the precedent that government can shut down a company if it violates environmental law.

Hyde continued to practice law at Bassford, Hecht, Lockhart and Mullin, then Gray, Plant Mooty, Mooty & Bennett. The work, mostly in the environmental realm, was complicated and challenging, but it could be fun, too.

Wade Anderson, an attorney at Gray Plant Mooty, recalled, "I was a young associate, and we were working on a complicated environmental matter … when Mac said, 'Let's go take a look at this property; I'll pick you up at the curb.' So I was waiting there and suddenly Mac pulls up in a black Mustang convertible, which really wasn't what I expected. There was a free spirit about him."

In 1995, at 60, Hyde decided to embark on a new career redeveloping environmentally contaminated brownfield sites by forming Real Estate Recycling LLC with his son Paul. "He has a real curiosity and drive to try new things and a fearlessness in doing it," his son said.

The business overhauled several Superfund sites and redeveloped several million square feet of industrial space in the Midwest.

Arne Cook, a friend and colleague, worked with Hyde on Real Estate Recycling's first brownfields redevelopment project in the Midway area, an abandoned nuts and bolts factory. "It was bombed out; it looked like Baghdad," said Cook, senior vice president at the Excelsior Group in Eden Prairie. Now it's a desirable office and industrial complex.

Last July, the company sold off most of its real estate portfolio to a Canadian company for $38 million, certainly a financial windfall that would guarantee a comfortable retirement. But Hyde, then 77 and found to have cancer, started another brownfields redevelopment firm with his son called Hyde Development.

Hyde enjoyed the outdoors, whether it was at the family cabin in Wisconsin, on the golf course or tennis court. He and his wife of 49 years, Joan Bissell Hyde, lived in the same house in Golden Valley for many years.

In addition to his wife and son Paul, Hyde is survived by a daughter, Kathryn Rachel Bartel, of Independence, and another son, David Bissell Hyde of Barnet, Vt. Services will be held at 2 p.m. Saturday at Westminster Presbyterian Church in Minneapolis.