The number of USTs in the U.S. regulated by the EPA that contain petroleum or hazardous wastes is approximately:

• A. One hundred
• B. One thousand
• C. One hundred thousand
• D. One million

Answer: (D)

The main idea here is the scale of underground storage tanks that the EPA regulates. USTs storing petroleum or hazardous liquids are widespread across the country—in gas stations, heating oil systems, and many industrial facilities—so the regulated population is very large. Because of this extensive presence and the EPA’s Subtitle I program to manage spill prevention, leak detection, corrosion protection, and proper closure, the approximate total is around the one-million mark. That reflects the broad footprint of USTs nationwide and why environmental compliance in property and lending contexts often focuses on UST-related responsibilities.