Waste Not, Want Not

Characterize chemical waste correctly to ensure safety & avoid fines and penalties.


A recent visit by state and federal inspectors brought to light the importance of knowing all your waste streams intimately. Working in a large academic research institution, with all its diverse classroom laboratories, research laboratories and support shops, is quite the challenge. And, sure enough, a few things slipped through the cracks. Sharp-eyed, experienced inspectors were able to uncover these transgressions without much effort, and the resulting fines were not insignificant. A reoccurring problem, though mostly concerning shop waste streams, was the failure to fully determine the hazardous characteristics of all wastes.

This month, we will provide an introduction and overview of waste characterization. Our focus will be on laboratory chemical wastes, since these are the main culprits when it comes to waste streams in research and production facilities, and determining whether they should be considered hazardous. Proper management of chemical waste is not only important for safety but also for economic health, as we found out given the serious fines and penalties possible if they are not handled according to regulations. We will zero in on the federal regulations dealing with hazardous waste characteristics.

Getting started — Know the rules

The Environmental Protection Agency (EPA) developed regulations, outlined in the Resource Conservation and Recovery Act (RCRA), for the treatment, storage and disposal of all hazardous wastes. RCRA defines those wastes that are hazardous, i.e., those that must be disposed of as hazardous wastes. The details are contained in the Code of Federal Regulations, Title 40: Protection of Environment, parts 260 to 265.1 We believe that most lab managers are well aware of the U-list and the P-list, specific lists of hazardous chemicals that, when disposed of, become hazardous chemical wastes. The U-list covers discarded chemical products, off-specification chemicals, container residues, and spill residues that have been identified as toxic wastes and receive a corresponding Ucode. The P-list refers to a special sub-list of compounds identified as acutely toxic and subject to smaller quantity exclusions. These lists are found in 40 CFR 261.33.

In addition, there are smaller lists for chemicals from nonspecific sources, mixtures of spent solvents, wastewater sludge and distillation bottoms that fall under the F-codes (found in 40 CFR 261.31). Wastes from specific procedures such as wastewater treatment sludge and distillation wastes from certain chemical production processes receive a K-code (found in 40 CFR 261.32).

Although federal regulation establishes a baseline, we must emphasize that some states and local jurisdictions have waste or chemical management requirements that go beyond the EPA. Therefore, it is critical to check with state and local entities regarding any additional requirements.

Next step — Identification

As a lab manager, the burden is on you, the generator, to characterize all wastes produced by the lab or facility. For the average laboratory, a waste is considered hazardous if any components are on one of the two lists of hazardous chemicals (P-list for acutely hazardous or U-list for general toxic chemicals). But what if your lab generates a waste stream that does not contain any U-listed or P-listed material and does not fall into one of the F- or K-listed categories? How do you make a determination of whether the waste is hazardous or not? Very simply, it must meet one of the hazardous characteristics: ignitability, corrosivity, reactivity or toxicity, as defined in 40CFR 261.20. In these cases, we would encourage you to contact an experienced consultant to assist in sampling and testing in order to determine whether the waste meets any hazardous characteristics. If the waste is not hazardous, then disposal via the sewer system or the general refuse collection might be an alternative. However, we caution you again to confirm with the local providers and authorities to ensure that all local codes and ordinances are followed.

The hazardous characteristics

Unconventional, temporary or short-term wastes must be fully characterized for proper disposal. Again, the four hazardous characteristics are ignitability, corrosivity, reactivity and toxicity. Actual testing is sometimes avoided with sufficient general knowledge, i.e., knowledge of the specific constituents used and the process by which the waste is generated. In most cases, however, representative samples are collected and tested to make the determination.

Ignitable wastes are given the code D001 and exhibit any of the following properties:

  • A liquid that has a flash point less than 60oC (140oF), determined by the Pensky-Martin Closed-Cup Tester or the Setaflash Closed-Cup Tester
  • A non liquid that is capable of causing fire through friction, adsorption of moisture or spontaneous chemical changes
  • Is an ignitable compressed gas as defined in 49 CFR 173.300
  • Is an oxidizer as defined in 49 CFR 173.151

Corrosive wastes are given the code D002 and exhibit any of the following properties:

  • Aqueous liquid with a pH less than 2 or greater than 12.5
  • A liquid that corrodes steel at a rate greater than ¼ inch (6.35mm) per year at a test temperature of 55oC (130oF)

Reactive wastes are given the code D003 and exhibit any of the following properties:

  • Is normally unstable and undergoes violent change without detonating
  • Reacts violently with water
  • Forms potentially explosive mixtures with water
  • Generates toxic gases or vapors when mixed with water
  • Is a cyanide- or sulfide-containing waste that can generate toxic gases or vapors
  • Is capable of detonation or explosion if subjected to a shock or heat
  • Is an explosive as defined in 49 CFR 173

Toxic wastes are given a D-code, according to Table 1 (below), if any of the toxic compounds present are equal to or above the respective limits as determined by the Toxicity Characteristic Leaching Procedure (TCLP). This is basically a water-extraction procedure for determining if toxic compounds can leach out of the waste. TCLP is defined in Test Method 1311.2


To operate safely and to avoid potential expensive regulatory fines, proper management of hazardous chemical waste is paramount. If you are new to handling laboratory wastes, this article should get you moving down the right path. If you are an experienced lab manager, then hopefully there is some useful information here to help you review your current operations. We look forward to lots of reader feedback. Stay safe!

M aximum Concentration of Contaminants for the Toxicity Characteristic

Categories: Lab Health and Safety

Published In

Hazcom 2012: Are You Prepared? Magazine Issue Cover
Hazcom 2012: Are You Prepared?

Published: June 1, 2012

Cover Story