Dow Chemical Company operated a 2,000-acre chemical manufacturing facility with numerous covered buildings in Midland, Michigan. Dow maintained extensive security around the facility. Security measures around the perimeter of the facility prevent ground-level public viewing, and Dow also investigates any low-level aircraft flights over the facility.

The EPA sought to inspect two of Dow’s power plants in the facility for violations of federal air-quality standards. Without obtaining a search warrant to enter the property and despite Dow’s refusal to voluntarily agree to a search, the EPA employed a commercial airplane with precision aerial-camera mapping equipment to photograph Dow’s large manufacturing and research facilities from the air. The powerful equipment allowed power lines as small as 0.5 inch in diameter to be observed. Yet, at all times, the aircraft stayed within navigable airspace.

Dow became aware of the EPA’s actions and claimed that its Fourth Amendment rights had been violated. Did the EPA’s photographs constitute an unreasonable search in violation of the Fourth Amendment? [Dow Chemical Co. v. United States, 476 U.S. 227 (1986).]