For hazardous waste generators, there are lots of options for disposal of hazardous waste streams…….recycling, fuel blending or simply burying in a landfill are just a few of the options available. When assessing options, many generators simply default to their preferred vendor on whatever is presented to them, without understanding all of their options……….many times to their detriment.

hazardous-materials-definitionPrice is usually the only factor considered, but there are other important things to consider including the environmental impact of these decisions and whether the resource that they are disposing of still has value, which is the essence of the circular economy.  

So where does a generator go to understand their waste streams.  It starts with an understanding of the right hazardous materials definition………. and how hazardous waste streams are classified.

Let’s start with the basics.

In the United States, hazardous waste is regulated by the Resource, Conservation and Recovery Act of 1976 (RCRA) which gives the Environmental Protection Agency (EPA) broad powers of authority to control hazardous waste from the "cradle-to-grave."  

EPA establishes the regulatory framework for managing hazardous waste including what materials are classified as hazardous.  Following is information on how materials are defined and classified.


What is Hazardous Waste?


Hazardous waste in the simplest terms is a waste with properties that make it potentially dangerous or harmful to human health or the environment. That is a very broad definition that covers a lot of substances and materials. The universe of hazardous wastes is large and diverse.

Hazardous waste streams come in many forms. For instance, they can be liquids, solids, or contained gases. They can be the by-products of manufacturing processes, discarded used materials, or discarded unused commercial products, such as cleaning fluids (solvents) or pesticides.


How Does EPA Classify Hazardous Waste?


In regulatory terms, EPA defines hazardous waste based upon the appearance on one of the four RCRA hazardous wastes lists (the F-list, K-list, P-list, or U-list).

hazardous-materials-definition-factoryListed wastes are those that are related to certain manufacturing processes, pharmaceutical wastes, and unused chemicals and are set apart from other hazardous wastes. Knowing which of your wastes fits under what list allows you to better manage each of your waste streams.

Here is a broader look at the listed wastes:


The F-list (non-specific source wastes): This list identifies wastes from many common manufacturing and industrial processes, such as solvents that have been used for cleaning or degreasing. Since the processes producing these wastes occur in many different industry sectors, the F-listed wastes are known as wastes from nonspecific sources. (Non-specific meaning they don't come from one specific industry or one specific industrial or manufacturing process.)


The K-list (source-specific wastes): This list includes certain wastes from specific industries, such as petroleum refining or pesticide manufacturing. Also, certain sludges and wastewaters from treatment and production processes in these specific industries are examples of source-specific wastes.

The P-list and the U-list (discarded commercial chemical products): These lists include specific commercial chemical products that have not been used, but that will be (or have been) discarded. Industrial chemicals, pesticides, and pharmaceuticals are example of commercial chemical products that appear on these lists and become hazardous waste when discarded.

These four lists each designate anywhere from 30 to a few hundred waste streams as hazardous. Each waste on the lists is assigned a waste code consisting of the letter associated with the list followed by three numbers.


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What Makes a Substance Hazardous?


Not all hazardous waste streams are regulated by listings, but may still fall under protective hazardous waste regulation due to the four characteristics of hazardous waste.  

Wastes may be hazardous wastes if they exhibit any one of the four characteristics of a hazardous waste (ignitability, corrosivity, reactivity, and toxicity) as defined in Article 3 of Chapter 11 of the hazardous waste regulations (Sections 66261.21 to 66261.24).

Let’s look at these characteristics a little more closely by referencing literature from EPA:.


hazardous-materials-definition-ignitabilityIgnitability – Ignitable wastes can create fires under certain conditions, undergo spontaneous combustion, or have a flash point less than 60°C (140°F). Examples include gasoline and used solvents. The characteristic of ignitability is defined in section 66261.21 of
the hazardous waste regulations.


Corrosivity – Corrosive wastes are materials, including solids, that are acids or bases, or that produce acidic or alkaline solutions. Aqueous wastes with a pH less than or equal to 2.0 or greater than or equal to 12.5 are  corrosive. A liquid waste may also be corrosive if it is able to corrode metal containers, such as storage tanks, drums, and barrels. Spent battery acid is an example. The characteristic of corrosivity is defined in section 66261.22 of the hazardous waste regulations.


Reactivity – Reactive wastes are unstable under normal conditions. They can cause explosions or release toxic fumes, gases, or vapors when heated, compressed, or mixed with water. Examples include lithium-sulfur batteries and unused explosives. The characteristic of
reactivity is defined in section 66261.23 of the hazardous waste regulations.

Toxicity – Toxic wastes are harmful or fatal when ingested or absorbed (e.g., wastes containing mercury, lead, DDT, PCBs, etc.). When toxic wastes are disposed, the toxic constituents may leach from the waste and pollute groundwater. The characteristic of toxicity is defined in section 66261.24 of the hazardous waste regulations.

Characteristic wastes, like listed wastes are also assigned waste codes. Ignitable, corrosive, and reactive wastes carry the waste codes D001, D002, and D003, respectively. Wastes displaying the characteristic of toxicity can carry any of the waste codes D004 through D043.

One final note, while this article focuses on how the EPA, a federal agency characterizes hazardous waste, it should also be stated that each state also has regulatory power over hazardous waste that can be more stringent than federal guidelines. 

California through the Department of Toxic Substances Control (DTSC) is one such example.


Why Is This So Important?


Resource stewardship is becoming an important aspect in product manufacturing and product lifecycle.  As concepts such as sustainability and circular economy gain increasing traction in our business community, the responsible planning, management and disposal of natural resources will become a priority for businesses.

For now, knowing which kind of waste streams and their characteristics that you’re generating will allow you to better handle, dispose, and treat them. Especially if you are transporting hazardous waste to Mexico.

By understanding the Environmental Protection Agency’s (EPA) more stringent rules on manifests and recordkeeping that go along with certain listed wastes, changes either in how those materials are disposed of, or whether there are acceptable material substitutes that are non-hazardous can improve or boost your bottom line.

Take a moment to understand how hazardous materials are defined and classified and what options you may have to make more informed business decisions.

Image Credit: Photo by ActiveSteve | CC BY


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