Understanding The Difference Between Spill Containment and Secondary Containment

Understanding the difference between spill containment and secondary containment is essential in maintaining a safe and regulation-compliant working environment wherever hazardous materials are found. Both forms of containment serve an important role in workplaces around the globe, protecting employees and the environment from dangerous liquids. Read below to learn about the difference between spill containment and secondary containment, as well as the different forms of secondary containment. 

What is the Difference Between Spill Containment and Secondary Containment? 

Spill containment and secondary containment work together to accomplish the same thing; they contain a hazardous liquid from spilling into the surrounding environment.  To understand the difference between spill containment and secondary containment, it can be beneficial to think of spill containment as the primary form of containment. It is the first line of defense in stopping a liquid from spilling and can take any number of forms. Drums, cans, bottles, and carboys are common examples of primary spill containment. 

Your secondary form of containment could be viewed as the backup plan. Should the primary form of spill containment fail, whether a drum is punctured or a carboy leaks, the secondary containment is in place to mitigate the damage by collecting or controlling the compromised container’s contents. Secondary containment can take many forms, including berms, pallets, absorbent pads, and more.  

What is the Purpose of Secondary Containment? 

Secondary containment plays a vital role in countless workplaces across the country as it helps to protect both workers and the surrounding environment. Secondary containment is intended to be used whenever hazardous liquids are stored or used. If a hazardous liquid were to spill without secondary containment in place, it could lead to unmitigated damage in the workplace as well as injury or fatalities amongst nearby team members. For this reason, the Occupational Safety and Health Administration (OSHA) has regulations regarding secondary containment requirements.  
 
Secondary containment also works to protect the surrounding environment as it prevents hazardous liquids from escaping into the surrounding environment and polluting the land, water, plants, and animals. This is why the Environmental Protection Agency (EPA) offers its own regulations regarding secondary containment in addition to those put forth by OSHA, as the EPA focuses primarily on the environmental implications of a spill while OSHA focuses primarily on the workers involved.  

Passive vs. Active Secondary Containment 

There are two different classifications of secondary containment, passive and active. The terms passive and active are referring to whether or not a form of secondary containment needs to be deployed at the time of a spill, or if it is already in place. Passive means of secondary containment are already in place prior to a spill and require no action on behalf of your team in order to do their job. Active forms of secondary containment, on the other hand, need to be deployed by your workforce as quickly as possible to mitigate the impacts of a spill. 
 
One obvious benefit of passive containment is the fact that it requires no human intervention in order to be effective, reducing the risk of containment failure due to human error.  Despite this, passive forms of secondary containment are not always practical or feasible depending on circumstance. Both active and passive forms of containment are common in workplaces across the United States.

Forms of Passive Containment

Passive containment can take many forms, including spill containment pallets, pre-installed dikes, and pre-installed spill containment berms. Each form of passive containment comes with its own pros and cons, and weighing them as you consider your specific work environment can help you select the most effective solution for your workplace.  

Forms of Active Containment 

Active secondary containment can also take many forms, including absorbent pads, manually engaged spill berms, socks, diverters, drip pads,  and oil solidifying polymers. Depending on the chemicals on site and the landscape of your workplace, you might find any one of these is a suitable secondary containment solution.  

Secondary Containment Volume Requirements

While choosing your secondary containment product, it is essential to ensure that the form of secondary containment will also meet secondary containment volume requirements. EPA code 40 CFR 264.175 states: "The containment system must have sufficient capacity to contain 10 percent of the volume of containers or the volume of the largest container, whichever is greater."

Justrite has provided an example to help explain:  

For the storage of two 55-gallon drums, your secondary containment will need to hold 55 gallons. Ten percent of the total volume of the two containers is less than that of a single 55-gallon drum.  For the storage of twenty 55-gallon drums, your secondary containment is required to hold a minimum of 110 gallons. This is because 10 percent of the total volume of twenty 55-gallon drums is 110 gallons. Because 110 gallons is greater than 55, this is the minimum you are required to adhere to. 
 
It is important to note that for passive containment utilized outdoors, employers also need to account for the potential for precipitation to build up within the secondary containment system. While it is acceptable for precipitation to build up within your secondary containment, the potential for precipitation accumulation needs to be accounted for when determining the volume requirements for your secondary containment system.  
 
This guide is intended to serve only as a reference to the reader. It is not a substitute for comprehensive knowledge of the safety procedures and regulations surrounding your specific materials, spill containment requirements, industry, and location. Justrite assumes no liability for the use or misuse of this information. 

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