California UST System Operator Practice Test

USTs, or Underground Storage Tanks, are primarily constructed from materials that can withstand the harsh environmental conditions and the corrosive effects of the substances they contain, such as fuels and chemicals. Steel, particularly when treated or coated to prevent corrosion, is a traditional material used for its strength and durability. However, there has been a significant shift towards using fiberglass-reinforced plastic due to its resistance to corrosion and chemical damage.

Fiberglass-reinforced plastic tanks are lightweight, resistant to the chemicals often stored inside, and do not require additional corrosion protection measures. The combination of steel and fiberglass is often utilized to optimize both structural integrity and resistance to the various substances stored within the tank. This makes the combination of both materials a common choice in UST construction.

Other materials listed have limitations: concrete can be porous and potentially allow leakage, PVC is not typically used for USTs due to its lower strength and durability, and wood is unsuitable because it deteriorates over time and is not resistant to the various chemicals stored in USTs. Thus, the combination of steel and fiberglass-reinforced plastic is widely accepted as the most effective and commonly used construction material for USTs.