Types of Hazardous Waste

Free HCS/HazCom 2012 Standards Guide

Written by Steve Hudgik February 2013

There are three types of hazardous waste:

1. Universal Waste
2. Characteristic Waste
3. Listed Waste

Types of Hazardous Waste - Universal Waste

The EPA has defined some common hazardous wastes as "Universal Wastes." These are materials that must be handled and disposed of in a proper manner, for which the EPA has established standards for handling and disposal. The objective is reduce the amounts of these materials going into the environment by making it easy to know how to handle and dispose of these common materials.

The Federal universal wastes are:

• batteries
• pesticides
• mercury-containing equipment 
• mercury-containing bulbs (lamps)

Before talking about the other two types of hazardous wastes, let's define the term "hazardous waste."

Types of Hazardous Waste - Definition Of Hazardous Waste

The statutory definition of hazardous waste is: "A solid waste, or combination of solid waste, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may (a) cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or (b) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed."

This definition serves as a general guideline indicating the types of wastes that are to be regulated. For waste generators and handles to know whether their wastes have a sufficient threat to warrant regulation or not more specific criteria is needed. This has resulted in the regulatory definition of hazardous waste.

Two different mechanisms are used in the regulatory definition: establishing lists of specific wastes that are identified as hazardous and identifying characteristics which, when the exist in in a waste, make that waste hazardous.

Types of Hazardous Wastes - Characteristics

A hazardous waste characteristic is a property which, when present in a waste, indicates that the waste represents a threat sufficient to merit regulation as a hazardous material.

When defining hazardous waste characteristics, the EPA asked the question, "what properties or qualities can a waste have which cause that waste to be dangerous?" They found that hazardous wastes have one (or more) of four characteristics.

For example, ignitability, or the tendency for a waste to easily catch fire and burn, is a dangerous property. Thus, ignitability is one of the hazardous waste characteristics. A waste displaying that property is regulated as hazardous.

• Ignitability
• Corrosivity
• Reactivity
• Toxicity

Testing For Hazardous Waste Characteristics

The EPA hazardous waste listings provide a description of wastes the EPA considers dangerous enough to warrant regulation. Hazardous waste listings identify wastes from various industrial processes, wastes from specific sectors of industry, and wastes in the form of specific chemical formulations.

Before adding a waste to a hazardous waste listing, the EPA thoroughly studies the waste stream and the threat it can presents to human health and the environment. If the threat is sufficient, the EPA develops a precise description of that waste and places it on the appropriate hazardous waste list. From that point on any waste fitting the description is considered hazardous, without regard to its chemical composition or any other variable.

Using listings makes the hazardous waste identification process easy for industrial waste handlers. They only need to know the waste's origin to determine if it is listed. A laboratory analysis is not necessary.

On the negative side, the use of listings requires an extensive study of each waste by the EPA. However, the EPA cannot investigate the countless different types of chemical wastes produced in the United States. As a result the hazardous waste listings cannot cover all hazardous wastes.

Another disadvantage of using hazardous waste listings is the lack of flexibility. The listings designate a waste as hazardous, if it falls within a particular category or class. The actual composition of the waste is not a consideration as long as the waste matches the appropriate listing description. However, some listed wastes, under some circumstances, may contain relatively few hazardous constituents . As a result they have a negligible risk to human health and the environment. These materials are still regulated as hazardous, however, because the listing does not take into consideration variations in waste composition. As a result the hazardous waste listings can unnecessarily regulate some wastes that do not have a significant health threat.

Types of Hazardous Wastes - The Four Hazardous Waste Lists

EPA has studied and listed as hazardous hundreds of specific industrial waste streams. They are divided into four lists:

1. The F list - designates specific solid wastes from some common industrial or manufacturing processes as hazardous. Because the processes producing these wastes can occur in different sectors of industry, the F list wastes are known as wastes from nonspecific sources. The F list is codified in the regulations in §261.31.
2. The K list - designates specific solid wastes from specific industries as hazardous. K list wastes are known as wastes from specific sources. The K list is found in §261.32.
3. The P list - identifies pure or commercial grade formulations of some unused chemicals as acute hazard. Both the P list and U list are codified in §261.33.
4. The U list - is similar to the “P list” in that it identifies pure or commercial grade formulations of certain some unused chemicals as toxic. Both the P list and U list are codified in §261.33.

Each list designates from 30 to a few hundred waste streams as hazardous. Each waste on these lists is assigned a waste code consisting of a letter, that identifies the specific list, followed by three numbers. For example, the wastes on the F list are assigned the waste codes F001, F002, and so on.

Types of Hazardous Wastes - Listing Criteria

Before any waste can be listed as hazardous, it is evaluated by the EPA. There are four criteria that are used to determine whether a waste is hazardous. These are:

1. The waste typically contains harmful chemicals, and other factors indicate that it could pose a threat to human health and the environment in the absence of special regulation. Such wastes are known as toxic listed wastes.
2. The waste contains such dangerous chemicals that it could pose a threat to human health and the environment even when properly managed. Such wastes are known as acutely hazardous wastes.
3. The waste typically exhibits one of the four characteristics of hazardous waste described in the hazardous waste identification regulations (ignitability, corrosivity, reactivity, or toxicity).
4. When EPA has to cause to believe for some other reason, the waste typically fits within the statutory definition of hazardous waste developed by Congress.

The majority of listed wastes fall into the toxic waste category. To decide if a waste should be a toxic listed waste, the EPA begins by determining whether it typically contains harmful chemical constituents. If it is determined a waste contains harmful chemical constituents, the EPA evaluates 11 other factors to determine if the waste stream could be be a threat should there are no restrictions on its handling.

Acutely hazardous wastes are the second most common type of listed waste. A waste is considered acutely hazardous if it contains constituents that scientific studies show to be fatal to humans or animals in low doses. The criteria for designating a waste as acutely hazardous require only that EPA consider the typical chemical makeup of the waste stream. EPA is not required to study other factors, such as the relative risk or evidence of harm, when listing a waste as acutely hazardous.

A hazard code is assigned to each listed waste to indicate the reason for its listing. These hazard codes are listed below. The last four hazard codes apply to wastes that have been listed because they typically exhibit one of the four regulatory characteristics of hazardous waste.

• Toxic Waste (T)
• Acute Hazardous Waste (H)
• Ignitable Waste (I)
• Corrosive Waste (C)
• Reactive Waste (R)
• Toxicity Characteristic Waste (E)

The hazard codes assigned to listed wastes affect the regulations that apply to handling the waste. For instance, acute hazardous wastes accompanied by the hazard code (H) are subject to stricter management standards than most other wastes.