fentress architects has been recognized as a pioneer in sustainable design since the early 1990s. the firm's green practices were acknowledged first in 1993 with the architecture and energy award for the natural resources building in olympia, washington. it was the first project to ever set indoor air quality improvement as a goal at the onset of design, which established a standard for the industry. fentress also designed dia (denver international airport), one of the largest daylit facilities ever built. the firm's sustainable design for the california department of education headquarters building – block 225 created the largest leed 2.0 gold rated building in the world, which became the second project in the world to achieve leed eb platinum in 2006. the majority of the firm's licensed architects are leed accredited professionals. fentress recently ranked among the top 25 green design firms by engineering news-record magazine, a leading publication in the design and construction industry.