The former Saltonstall building at 100 Cambridge St. in downtown Boston has been awarded LEED Silver certification.

The Boston building earned its certification under the LEED for Existing Buildings: Operations & Maintenance Rating System with a goal of maximizing operational efficiency while minimizing environmental impacts, according to a statement. The building is one of only 12 Boston buildings to earn USGBC LEED for Existing Buildings certification, according to a statement.

"This LEED Silver certification shows that 100 Cambridge St. has come a long way from the time it was declared a sick building and closed in 1999," said MassDevelopment President and CEO Robert L. Culver. "MassDevelopment is committed to making green practices a priority in construction and renovation, and we’re pleased USGBC has recognized our work at 100 Cambridge."

In 1999, the commonwealth of Massachusetts closed the Leverett A. Saltonstall state office building and selected MassDevelopment to redevelop the contaminated property, according to a statement. The mixed-use 600,000-square-foot property was rehabbed and rebranded 100 Cambridge St.

LEED certification of 100 Cambridge St. was based on new, water-efficient plumbing fixtures, enhanced single-stream recycling, lighting upgrades with sensors, and the introduction of USGBC policies for indoor air quality and "green" cleaning.