Compliance Corner.

Secondary Containment Requirements

EPA imposes secondary containment standards on permitted facilities that handle hazardous waste containers. The agency’s logic in including this provision is explained as follows:

“Containers are relatively thin-walled, can be punctured by fork-lift trucks, and are prone to break open when dropped or knocked over. They tend to corrode or otherwise deteriorate relatively rapidly both from the inside as a result of reaction with the waste, and from the outside as a result of exposure to the environment. The agency believes, therefore, that it is prudent to require a secondary containment system under container storage areas.” [46 FR 2829]

Only RCRA-permitted facilities are required to provide secondary containment for hazardous waste containers. Secondary containment for containers does not need to be certified by a professional engineer. [RO 12094] Although many generators and interim status TSDFs do provide secondary containment for these units as a matter of good housekeeping (i.e., to catch drips and spills), it is not required per federal regulations. Such facilities should check with their state RCRA authority to determine any state program requirements for container secondary containment. [RO 11909]

Technical details

A typical containment system consists of a poured concrete pad with curbing to prevent a release of hazardous waste into the environment; the pad is often sloped to a sump for removal of any leakage or other liquid drainage. Secondary containment requirements for permitted facilities are spelled out in §264.175 and are summarized below.

• Containment systems must have a base that is sufficiently impervious so as to contain leaks, spills, container failures, and run-on/precipitation until the collected material is detected and removed. Typically, such bases are made of concrete or asphalt, but other materials may be used. The regulations do not require that a liner or coating be used in conjunction with a concrete containment system. [RO 11909]
• The capacity of the secondary containment must hold the larger of 1) 10% of the volume of all containers protected by the system, or 2) the volume of the largest single container protected by the system. Containers not holding free liquids need not be considered in this determination (under either approach), unless the solids carry the following waste codes: F020, F021, F022, F023, F026, or F027.
• Run-on must be prevented from entering the containment system, unless enough capacity (in addition to that required above) has been built into the system to hold any run-on that might enter.
• The containment must be sloped or otherwise designed and operated to drain and remove liquids resulting from leaks, spills, container failures, and run-on/precipitation, unless the containers are elevated or otherwise protected from contact with accumulated liquids. The agency expects that by one hour after a leak or storm, no standing liquid will remain on the base in contact with the containers. [46 FR 2830] Palletizing drums to elevate them above accumulated liquid obviates the need for a sloped storage pad. [46 FR 2830]
• Spilled or leaked waste and any collected run-on/precipitation must be removed from the sump or collection area in a timely manner to prevent the collection system from overflowing.

Secondary containment exemption

EPA provides an exemption to container secondary containment for permitted TSDFs. Container storage areas that hold only hazardous waste with no free liquids (as demonstrated by the paint filter test) do not need secondary containment if 1) the storage area is sloped or otherwise designed and operated to drain and remove liquids resulting from run-on/precipitation; or 2) containers are elevated or otherwise protected from contact with accumulated liquids. [§264.175(c)]

This exemption does not apply to areas storing containers holding the following types of listed dioxin wastes, regardless of whether the containers hold free liquid or not: F020, F021, F022, F023, F026, and F027.