What is a Hazardous Waste?

Hazardous Waste Determination Worksheet

In order to determine proper handling procedures and disposal, a decision must be made regarding whether the chemical waste is a hazardous waste, or is otherwise regulated. Connecticut DEEP and federal EPA regulations (40 CFR, Part 261) define various categories of hazardous and regulated chemical wastes. A hazardous waste as defined by RCRA, is any discarded material that is not excluded by the regulations and that meets either of the following criteria:

It exhibits one or more of the following hazardous waste characteristics, as defined in Subpart C of 40 CFR 261:

All wastes (unless specifically excepted) are subject to classification according to their characteristics. The general characteristics of Ignitability (D001), Corrosivity (D002) and Reactivity (D003), and Toxicity (D004-D043) are summarized below.

Ignitability - Wastes capable of causing a fire or sustaining an existing fire. Specifically waste with a flash point less than 140 °F (60 °C) for liquids, non-liquids capable of causing fire under standard temperature and pressure, and ignitable compressed gas or an oxidizer as defined by the Department of Transportation.

Corrosivity - Wastes which corrode metals or other material. Specifically aqueous wastes having a pH less than or equal to 2, or greater than or equal to 12.5; and liquid wastes that corrode steel at a rate greater than 0.250 inches (6.35 mm) per year at a temperature of 130°F (55°C).

Reactivity - Unstable wastes having a tendency to react violently or explode. Specifically wastes which react violently with water, wastes that form potentially explosive mixtures with water, or wastes when mixed with water produces toxic fumes in a quantity to present a danger to human health or the environment. In addition wastes that contain cyanide or sulfide which when exposed to pH conditions between 2 and 12.5 generate toxic gases, wastes capable of detonation or reaction if subjected to a strong initiating source or if heated under confinement, or wastes that are readily capable of detonation or reaction at standard temperature and pressure.

Toxicity - D-Listed Wastes (Waste Codes D004-D043). Wastes capable of leaching into the surrounding environment. Specifically, wastes that fail the Toxicity Characteristic Leaching Procedure (TCLP) test method, indicating the waste contains contaminants equal to or greater than concentration levels established in Table1, Title 40 CFR 261.24.

Or... It is specifically listed in Subpart D of 40 CFR 261:

Used Chemicals:

F-Listed Wastes (Commonly found wastes, ranging from solvents to wastewater treatment sludges.)
K-Listed Wastes (Wastes that are generated from specific processes or sources within certain industries. K-Listed wastes are not generated at Connecticut College.)

Unused Chemicals:

P-Listed Wastes (Chemicals that are considered to be "acutely" hazardous, because of their high toxicity), and
U-Listed Wastes (Chemicals that are considered waste because they are no longer needed, they are spilled, or they are off-specification.)

In addition, Used Oil containing more than 1000 ppm total halogens must also be managed and disposed of as hazardous waste.

Hazardous Waste Characterization

The individual generating the waste is responsible for determining if the waste is a "Hazardous Waste" as defined by regulation. This can either be done by:

  • Testing the waste according to the methods set forth in Subpart C of 40 CFR part 261, or...
  • Applying knowledge of the hazardous characteristic(s) of the waste in light of the materials or the processes used ("knowledge of process")

A generator can use his/her knowledge of a waste to make a determination as to whether the waste is a characteristic hazardous waste. In order to use knowledge to characterize the waste, the generator must consider the raw materials that constitute the waste, and/or the process(es) that result in the waste being generated.

In considering the materials that make up the waste, the generator needs to examine the specific chemical and physical characteristics of the waste material. Information such as Material Safety Data Sheets (MSDSs) can be a helpful resource. However, while MSDSs can provide useful information regarding ignitability (flash point), corrosivity (pH), and reactivity, they tend to be less useful when it comes to identifying the toxic characteristics of waste. MSDSs do not include all of the ingredients in a certain material, but only those that make up greater than 1% of the total constituents of that material. This means that a waste may contain a toxic constituent exceeding the regulatory limit (making it a hazardous waste), but this constituent may not necessarily be included on the MSDS. Generators should also be aware that MSDSs are representative of raw materials; the MSDS may not accurately represent a waste material that is generated by the use of a particular raw material.

In considering the process that generates the waste, the generator needs to ask himself/herself: How does the operation/process affect the waste? For example, does the process make the waste ... more concentrated? ... more dilute?... contain free liquids?... become contaminated? etc.

One critical factor in using knowledge to characterize waste is that the knowledge must be applied appropriately. In other words, the knowledge that is applied must be valid and verifiable. A generator should not just assume that a waste is non-hazardous without providing some type of supporting, verifiable information to justify that conclusion. Using knowledge of the waste to conduct a hazardous waste determination involves a well-thought-out process in which the waste materials or the process generating the waste are considered. It should be noted that, more often than not, it is easier to use knowledge of the waste to characterize it as hazardous than it is to characterize it as non-hazardous.