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What's the Difference Between a "Containment System" and a "Secondary Containment System"?

Marcus Williams - Friday, July 29, 2016

What’s the difference between a Containment System and Secondary Containment?


If you have hazardous waste on your property, you must also have a system for safely containing that waste if it leaks or spills. Containment systems and secondary containment systems are both designed to protect people, property, and the environment from exposure to toxic spills. They both play important roles in transporting, treating, storing, and disposing of hazardous materials. However, they are regulated differently by the Environmental Protection Agency (EPA) because they serve unique purposes.


The Resource Conservation & Recovery Act (RCRA), which granted the EPA this authority in 1976, lays out the current requirements for hazardous substances. If you work with waste or toxic chemicals in any capacity, you must use equipment that meets these strict federal safety regulations. That includes a containment system that falls under the right category and handles your specific substances correctly.

Containment Systems

According to the RCRA guidelines for containing hazardous materials, containment systems are designed and used to manage hazardous waste in portable containers.

Examples of Containment Systems

Containment systems come in a wide variety of shapes and sizes, just like the containers they support. You may use one of the following containment systems in conjunction with your portable containers:

  • Pallets
  • Decks
  • Wood grids
  • Grated basins


Containment systems must be able to hold a certain amount of liquid, but capacity requirements depend on the containers that each system supports. Your containment system must be able to hold one of the following (whichever is greater):

  • 10% of the total volume of all containers
  • 100% of the biggest container's volume

These systems should also prevent the accumulation of spilled liquids. They often have grated or ventilated surfaces that allow liquids to drip down into a basin, but if not, they must be sloped or elevated to prevent pooling. If your containment system includes a drainage valve, you must meet additional EPA regulations for safe drainage.

Secondary Containment Systems

The EPA has a separate definition for secondary containment systems, which are sometimes called "spill containment systems" by vendors and businesses. According to the RCRA, secondary containment systems are supplements to stationary tanks, and must be used in conjunction with any tanks that contain hazardous materials.

Examples of Secondary Containment Systems

Secondary containment systems range from underground systems that manage waste near highways to simple systems under aquariums and water heaters. Some common secondary containment systems for industrial purposes include:

  • Drip trays – heavy duty containers that collect small leaks to prevent fire and toxic leaks; usually made of steel or plastic
  • Bunds – brick, mortar or concrete walls around tanks and drums; some have insulation to increase their boiling points
  • Pipes – concentric pipes may serve as protective outer shells for tanks and pipes; they may slope to funnel spills into a container with warning sensors
  • Sumps – a low basin, space or pan that collects runoff water or fuel
  • Ventilation systems – building features that redirect the flow of waste in case of contamination; common in the nuclear industry


You must install your secondary containment system before putting any new tank system into service. This containment system must be designed to accomplish the following:


  • Prevent the migration of waste into nearby groundwater, soil, or surface water while the tank is in use
  • Detect and collect any released liquids until they can be removed
  • Prevent failure or damage due to water pressure, wear and tear, vehicles, or weather (strong, thick linings may protect systems that aren't strong enough)
  • Include a leak detection system that detects failure within 24 hours
  • Drain and remove liquids that are spilled or leaked into it (sloped designs and valves)


A containment system must also be installed on a strong foundation, which can support the system and any extra compression or settlement due to changes in pressure.


Choosing the Right Containment System

The primary difference between these two systems is clear: containment systems are portable, while secondary containment systems remain stationary. However, choosing the right spill containment products isn't as simple as that. You must also meet local and federal codes for chemical resistance, fire safety, disposability, and loading methods. For example, wood and fiberglass grids cannot contain corrosive chemicals. You need steel or high-density polyethylene containment systems for any hazardous waste with a pH below 2.1 or above 12.4. Be sure to make all the proper considerations when constructing your own containment system.