In 1972, FHWA used 5 inches of scrubber waste in a parking-area base at Washington's Dulles Airport. 2 years later, wet weather caused the experimental base to soften and be replaced

Early tests explored scrubber waste for road bases and subbases. Florida projects between 1977 and 1989 showed highly satisfactory performance. Pennsylvania roads survived severe freeze-thaw conditions, proving successful. Texas and Ohio tests compared FGD material with gravel and haul road applications.