Virtually every regulatory agency has regulations that require companies to fulfill very specific compliance requirements. Sometimes, there is overlap and businesses may be required to comply with similar—yet different—regulations from two different agencies. Using containers to store hazardous waste products is one of those tricky situations.

Different Definitions

Containers used for hazardous materials or waste are regulated under the Department of Transportation’s (DOT) Hazardous Materials Regulations (HMR) (49 CFR 173.29) and the Environmental Protection Agency’s (EPA) Resource Conservation and Recovery Act (RCRA) Hazardous Waste Requirements (40 CFR 261.7). The confusion between these rules comes in the definition of empty, which changes significantly from one agency to the next.

For both agencies, the definition of empty dictates how containers that once held hazardous waste and/or hazardous materials are managed (i.e., shipped and disposed of). However, a container can meet the criteria for emptiness according to EPA but still not be considered empty according to DOT for transportation purposes. It is important to understand the different definitions to be able to comply.

EPA RCRA-Empty

The EPA regulations regarding management of empty containers and residues establish procedures for determining if a container is empty (i.e., no longer contains hazardous waste) and defining when hazardous waste residue in an empty container is exempt from regulation. According to EPA, an empty chemical container has been removed of all materials or liquids via commonly employed practices (e.g., pumping, pouring, or aspirating). But what does this actually mean?

RCRA-empty conditions differ based on whether the container is holding non-acute hazardous waste, acute hazardous waste, or hazardous waste in compressed gas form, as shown in the table below.

Containers that meet the definition of RCRA-empty are exempt from requiring specialized management as a hazardous waste. RCRA-empty containers can be disposed of at an authorized municipal solid waste landfill, recycled through a legitimate recycler, or reused onsite. Reuse requires properly emptying the container to avoid mixing incompatible substances that may create human health or environmental concerns. If a container is not found to be RCRA-empty, any residues removed from the container must be managed as hazardous waste under Subtitle C.

DOT Empty

DOT is responsible for hazardous materials shipping regulations. Unlike RCRA, DOT hazards are not defined by the quantity of material in the container; rather, the properties of the material dictate hazards. Even when a container appears empty, the hazardous material residue may still pose a hazard under the HMR. Per 49 CFR 173.29(a), these containers must follow the same rules as full hazmat containers when it comes to shipment. This includes having shipping papers, placards, labels, and markings, as well as providing training for employees who prepare the containers (full or empty) for shipping.

A container that once held hazardous materials is only considered exempt from HMR under the following conditions:

• The container remains unused.
• The container has been thoroughly cleaned and sufficiently purged of vapors to eliminate potential hazards.
• The container has been refilled with non-hazardous material to neutralize any remaining hazards from residue.

In addition, if the material inside the container is a DOT Class 9 material and meets the definition of RCRA-empty, the container is exempt from both EPA hazardous waste and DOT hazardous material shipping requirements.

Containers that meet the DOT criteria for being truly empty must have any hazard labels, markings, or placards that would be visible in transportation removed, covered, or obliterated to ensure emergency responders can correctly identify that the package contains no regulated hazardous materials.

Empty, Full, or Both?

In short, it is possible to have a container that EPA considers empty, but DOT does not. In this case, if you plan to ship the container, you would not have to follow any EPA hazardous waste rules, but DOT HMR would still apply when shipped.

A regulatory applicability assessment is a good first step in determining which regulations apply if you store hazardous waste in containers and/or plan to ship hazardous materials. If DOT’s HMR and EPA’s RCRA Hazardous Waste Requirements, it is then important to understand the distinction between the rules regarding what is considered empty to comply with both agency’s requirements.