When it comes to hazardous waste containers, what appears empty to you might not be considered so by the EPA. So the containers themselves might be subject to hazardous waste regulation, and inadvertently mishandling them can run you afoul of the law, even after having complied carefully with all hazardous waste management mandates for the material itself.
Regulations defining whether containers are truly “empty” in the eyes of the EPA—and therefore exempt from hazardous waste disposal regulations—are detailed in the federal Resource Conservation and Recovery Act (RCRA). Thereby, in hazmat lingo, the question of import is whether or not a container is “RCRA empty.”
Three different standards
The EPA prescribes three different “emptiness” standards that are necessary and sufficient to avoid hazardous material removal regulations. One is simply for “hazardous waste,” another for “acute hazardous waste,” and a third for “compressed gas hazardous waste.”
1. Hazardous waste
Under this standard, a hazardous waste container (or its inner liner) is considered RCRA empty after all possible waste has been removed from it by pouring, pumping, or suction so that no more than one inch of residue remains. This is referred to as the one-inch rule. But there’s more:
For containers (or inner liners) up to and including 119 gallons capacity, applicable rules for hazardous material disposal still apply if what’s left represents more than three percent of the hazmat by weight.
For containers (or inner liners) greater than 119 gallons capacity, applicable rules for hazardous material disposal still apply if what’s left represents more than three tenths (0.3) of a percent of the hazmat by weight.
These RCRA standards are also typically applicable where the residual hazardous waste is a mixture of both solid and liquid. However, as in all matters regarding hazardous material disposal, expert advice is crucial.
2. Acute hazardous waste
A hazardous waste is called “acute” when it’s determined that even a small amount of exposure to it might have severe effects on human health. Thereby, RCRA standards are more stringent about residual amounts of acute hazardous waste.
In effect, there can be no residue. Containers (or inner liners) that have contained acute hazardous waste must be triple-rinsed with an appropriate solvent—or cleaned by another method that has been proven the equivalence of a triple-rinse.
Again: expert advice is crucial. Specific federal guidance is conspicuously lacking about what constitutes a triple-rinse. And individual states and jurisdictions might have their own rules.
3. Compressed gas hazardous waste
Rules for residual compressed gas hazmat are less complicated. A container holding compressed gas is RCRA empty at the point where pressure inside the container is equal to atmospheric pressure in practical terms. This, of course, requires opening the container—so that applicable rules, regulations, and common sense precautions specific to the particular gaseous hazmat must be observed.
You might suppose that hazardous wastes and/or residue remaining in a container (or inner liner) deemed RCRA empty are exempt from EPA hazardous waste disposal rules. This is true for the most part, but you must determine whether removal of the original waste (or its subsequent management) doesn’t in itself produce a hazardous waste. An example might be the residual mixture of waste and cleaning solvent (aka rinsate) left from a triple-wash regimen.
You can avoid the time and expense of handling your empty hazmat containers (or inner liners) as hazardous materials themselves if you can make them RCRA empty, which will also allow you to pursue other recycling or reconditioning options. But as with all EPA regulations, caveats abound, and at the risk of redundancy: Expert advice is crucial!