Fiberglass Underground Petroleum Storage Tanks

Containment Solutions tanks are the finest quality petroleum storage tanks for underground systems. Unlike underground steel tanks, Containment Solutions petroleum storage tanks are backed by an industry best 30-year corrosion limited warranty.


Double Wall Tanks

With more alternative fuels being introduced to the marketplace and steel tank providers decreasing warranties due to corrosion issues, petroleum storage decisions can get complicated. Fiber Glass Systems is here to simplify the problem. FGS manufactures CSI tanks, the finest quality petroleum storage tanks for underground systems. Unlike underground steel tanks, CSI petroleum storage tanks are backed by an industry best 30-year corrosion limited warranty. Our double-wall fiberglass tanks are inherently non-corrosive, safely storing standard petroleum fluids, biofuels and biodiesels, ethanol and ethanol blends, ultra-low sulfur diesel (ULSD), even Diesel Exhaust Fluid (DEF).

Long-term corrosion and material properties testing is done at our Research and Development Center. Laminate testing includes current fuels, blends and other oxygenates, but we do not stop there. We also test alternative products and blends that could be stored in our CSI tanks in the future. As fuel options change, your petroleum storage tank compatibility will not. Many of the newest industry fuels and biofuels are alcohol based. Alcohol blends, including ethanol, increase the likelihood of water in a storage tank, resulting in rust and microbial-induced corrosion (MIC) in steel tanks. The inherent non-corrosive nature of a fiberglass CSI double-wall tank eliminates the possibility of rust on all tank wall surfaces.

Choosing the right fueling location is an important decision, choosing the right petroleum storage tank is imperative. Tank related issues are costly and can lead to environmental catastrophes. Trust the tank that changed the industry, trust a CSI double-wall petroleum storage tank.

Triple Wall Tanks

We also offer a triple-wall fiberglass tank for use in environmentally sensitive areas where tertiary containment is required. The triple-wall tank design provides secondary containment for the standard secondary containment system. Triple-wall tanks offer three levels of containment protection: the proven strength and performance of a primary fiberglass tank, and in the unlikely event that there is a breach, secondary and tertiary walls designed to contain the fuel and prevent any spill into the environment.

Triple-wall petroleum tanks, like single and double-wall models, come with a standard 30-year structural and corrosion limited warranty.


  • Our fiberglass storage tanks are not susceptible to the corrosion that exists in storing ethanol-blended fuels, biodiesel fuels, and ultra-low sulfur diesel (ULSD).
  • Our tanks are not susceptible to rust created by corrosive soil environments.
  • From our automated process, and the time and attention we put into each product, we set the industry standard for quality and safety.
  • The innovative tank design we use today originated from Owens Corning.
  • This design resulted in the UL1316 specification which governs underground fiberglass tank manufacturing still to this day.

Storage Solutions

  • Hazardous and Non-Hazardous Fluids
  • Flammable and Combustible Fluids
  • All Blends of Alcohol and Ethanol
  • Diesel Exhaust Fluid (DEF)
  • Biofuels
  • Containment Solutions Capabilities Brochure

  • Containment Solutions Capabilities Brochure (Spanish)

  • Containment Solutions Tank Sumps Brochure

  • Containment Solutions Tank Sumps Brochure (Spanish)

  • We, the Doers - QualityQuality you can rely on. Service you can trust.

  • We the Doers Campaign Quality Flyer (Spanish)

Aerial view of fiberglass tanks on gas station job site.
Two fiberglass tanks on job site with worker on top of tank.
Fiberglass tank being lifted off delivery truck with a crane.

Related Products

HydroGuard System

The most dependable storage system available.

Learn more

Fiberglass Underground Compartment Storage Tanks

Containment Solutions compartment tanks are built by dividing a double-wall storage tank with a bulkhead, creating two independent storage areas. Making them ideal for storing multiple blends for fuel.

Learn more

Fiberglass Underground Storage Tank Accessories

Our goal is to package a complete system for your project needs to avoid complications and excessive costs and reduce installation time.

Learn more

Red Thread IIA Riser Pipe

The industry’s first corrosion-resistant fiberglass riser pipe.

Learn more

Explore More

Underground installation of pipeline tanks, separated into 4 parts, with employees around and on the tanks

Fiber Glass Systems

With manufacturing facilities located around the world, we provide composite piping systems, fittings, and structures to the oil and gas, chemical, marine, offshore, fuel handling, and mining industries.

Learn more
Machinery picks up a line of composite pipe

Composite Solutions

Our composite solutions are designed to address weight- and corrosion-related challenges.
Learn more