Helen Wallbank Milliken, Michigan's longest-serving first lady and a staunch supporter of women's rights and environment issues, has died. She was 89.

Son William Milliken Jr. says she died Friday morning at the family's Traverse City, Mich., home.

Early in her husband's political career, Milliken dutifully played the role of unassuming, supportive spouse. But she evolved into an outspoken advocate of issues close to her heart during a record 14 years as first lady.

She vigorously campaigned for abortion rights and the ill-fated Equal Rights Amendment. She also drew the wrath of the outdoor advertising industry when she criticized highway billboards shortly after her husband, Republican William Milliken, became governor in 1969.

At her urging, her husband hiked the Pigeon River State Forest, where he later limited development.