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What Are The Requirements For Hazardous Substance USTs?

Underground storage tank (UST) systems that store substances identified as being hazardous under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) are subject to the same requirements as petroleum UST systems except that hazardous substance tanks must have secondary containment. Hazardous wastes are already regulated under Subtitle C of the Resource Conservation and Recovery Act (RCRA) and therefore are not covered by the UST regulations.

Currently about 1,200 substances (excluding radionuclides) are identified as hazardous under CERCLA (see 40 CFR 302, section 302.4).

What Requirements Apply To Hazardous Substance USTs?

Hazardous substance USTs have to meet the same requirements for petroleum USTs concerning correct installation, spill, overfill and corrosion protection, corrective action, and closure.

In addition, hazardous substance USTs must have secondary containment and interstitial monitoring for leak detection, as described below.

What Is Secondary Containment?

All hazardous substance USTs must have secondary containment. A single-walled tank is the first or primary containment. Using only primary containment, a leak can escape into the environment. But by enclosing an UST within a second wall, leaks can be contained and detected quickly before harming the environment.

There are several ways to construct secondary containment:

What Is Interstitial Monitoring?

The hazardous substance UST must have a leak detection system that can indicate the presence of a leak in the confined space between the first and the second wall. Several devices are available to monitor this confined interstitial space. (Interstitial simply means between the walls.) The UST regulations describe these various methods and the requirements for their proper use.

You can apply for an exception, called a variance, from the requirement for secondary containment and interstitial monitoring. To obtain a variance you must demonstrate to the regulatory authority that your alternative leak detection method will work effectively by providing detailed studies of your site, proposed leak detection method, and available methods for corrective action.

What About Leak Detection?

All UST systems are required to have leak detection, and the method must be properly operated and maintained.

What About Spill, Overfill, and Corrosion Protection?

All UST systems are required to have spill, overfill, and corrosion protection.

What If You Have A Hazardous Substance Release?

Whether you have a confirmed release, or even if you suspect that you might have a release, you must follow the basic actions described below:

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