The determination that made Arlene Blum a history-making mountaineer is apparent, nearly four decades on, as she walks her favorite trail in Tilden Park. You see it not so much in the hike itself, which is gentle enough for business meetings — she calls this placid stretch of green and gravel “my office” — but in how she views a signal breakthrough in her campaign to get toxic chemicals out of America’s furniture.

Breakthroughs appeared unlikely in 2007, when Blum set her sights on reducing the widespread use of flame retardants, a threat few were even aware of. She had just returned as a visiting scholar to UC Berkeley — where she earned a Ph.D. in biophysical chemistry in the 1970s — when she discovered alarming levels of PBDEs in the blood of her cat Midnight, then suffering from hyperthyroidism and severe weight loss. She learned that the disease, unseen in cats until 1979, had become epidemic…

Barry Bergman