• There are over 500 listed hazardous wastes.
• Unused discarded products include those that are spilled by accident as well as products that are intentionally discarded.
• Acute hazardous wastes are so dangerous in small amounts that they are regulated in the same way as large amounts of other hazardous wastes.

Some wastes are hazardous because they are known to pose a threat even when properly managed, regardless of their concentrations. The Environmental Protection Agency (EPA) says it has studied and listed as hazardous hundreds of specific waste streams. In fact, there are over 500 listed hazardous wastes.

There are four hazardous waste lists. They can be found in Part 261 Subpart D. These lists are:

F list (261.31): These are common wastes from nonspecific sources.

The F list is made up of the following groups:

• Spent solvent wastes,
• Electroplating and other metal finishing wastes,
• Dioxin-containing wastes,
• Chlorinated aliphatic hydrocarbons production wastes,
• Wood preserving wastes,
• Petroleum refinery wastewater treatment sludges, and
• Multi-source leachate.

The F listings refer to “processes only” rather than to specific industries and include wastes from common industrial and manufacturing operations. Because these wastes aren’t industry specific, they are generated by a very large number of facilities.

K list (261.32): These are wastes from specific industries.

Examples include:

• Wood preservation
• Inorganic pigments
• Organic chemicals
• Inorganic chemicals
• Pesticides
• Explosives
• Ink formulation
• Secondary lead
• Coking
• Petroleum refining
• Iron and steel
• Primary aluminum
• Veterinary pharmaceuticals

K wastes are partially defined by the industry in which they are generated and may be unit specific. The industry name for each waste group is listed in the EPA waste number column.

To determine if a waste is a K waste, first determine whether the waste fits within one of the 13 different K list industries.

P list and U list (261.33): These are discarded off-specification, or expired virgin commercial chemical products.

Unused discarded products include those that are spilled by accident as well as products that are intentionally discarded.

Examples include:

• Off-specification commercial chemical products, residue, soil, or debris contaminated by P or U chemicals.
• Container or inner liners removed from a container that held P- or U-listed chemicals. P listings are acutely hazardous wastes. U listings contain toxic constituents. Both the P and the U lists have a narrow applicability to unused commercial chemical products and manufacturing chemical intermediates. Any chemical which has been used for its intended purpose does not meet the P or U listing.

To be a P or a U chemical, the following criteria must be met:

1. The waste must be of a commercially pure grade or technical grade of the chemical that is produced and marketed; and
2. The chemical must be the sole active ingredient, or the only chemically active component for the function of the product. If a product has more than one active ingredient, it would not qualify as a P or U waste. Inert ingredients, such as fillers, do not prevent a P or U listing. For example, a commercial chemical product containing three percent Kepone as the only active ingredient would be a U listed waste, even though the chemical made up only a small percentage of the product.

Acute hazardous waste

Acute hazardous wastes are a special category of listed hazardous waste. These wastes are so dangerous in small amounts that they are regulated in the same way as large amounts of other hazardous wastes. Many pesticides or dioxin-containing wastes are acutely hazardous wastes.

The important thing to note about these wastes is that if the facility generates as little as 2.2 pounds — approximately one liter — of acutely hazardous wastes in a month, or accumulates that amount over time, the facility must comply with all the regulations that apply to large quantity generators (LQGs) of hazardous waste.

All P codes and all listed hazardous waste codes with an “H” hazard code are acutely hazardous, triggering LQG status at 2.2 pounds.