Beginning in the 1990's, the EPA recommended builders follow the Radon Prevention in the Design and Construction of Schools and Other Large Buildings. The recommendation calls for the construction of one radon pit per 100,000 square feet. These pits prevent radon accumulation in buildings. Metro Schools has installed these pits in new renovations and construction. Below is a list of schools that have undergone significant or new construction since the mid-1990s have included radon mitigation in their design.