March/April 1996
Like the mythical phoenix, incinerator scrap has risen from the ashes to become a significant and increasingly competitive recycling niche. Recyclers interested in this material, however, should know a few facts to avoid potential environmental liability.
By R. Michael Sweeney
We’ve all heard the saying that “one man’s trash is another man’s treasure.”
It’s a statement that’s especially true when you’re talking about metal scrap recovered from municipal waste-to-energy (WTE) incinerators—material that homeowners and businesses threw in the garbage can but recyclers and incinerator operators rescued, giving it a second chance at recycling.
Among its attributes, such incinerator scrap—which consists primarily of ferrous material—offers a consistent chemistry, dependable supply, and lower price tag than comparable grades, all of which makes it a marketable commodity, say recyclers who handle the material. It’s not surprising to learn, then, that since the early 1980s, when a handful of processors began recycling incinerator scrap, this niche has grown substantially and become increasingly competitive.
But while this market can be profitable, it is not for the environmentally unsophisticated. In short, recyclers who handle incinerator scrap could face environmental liability tied to the potentially hazardous nature of incinerator ash—from which much of such scrap is recovered (some metals may be removed prior to burning). As a result, it’s crucial for recyclers interested in this niche to understand a few basics about handling this material safely.
Incineration Basics
To better comprehend the potential liability related to incinerator ash, it’s helpful to understand the process that generates such ash and the recent controversies surrounding ash handling.
Incineration is a controlled combustion process in an oxidizing atmosphere that produces gases (chiefly carbon dioxide and water vapor), heat that can be converted to energy, and residual ash.
Most ash—around 85 percent—is what is called bottom ash, a heavy, noncombustible material that falls off the end of the combustion chamber’s furnace grate. The bottom ash contains few if any toxic metals or other constituents and is where recyclable metal scrap included in the burn ends up.
The remaining ash fraction is known as fly ash, a fine particulate matter that exits the furnace with combustion gases. In contrast to bottom ash, fly ash—which is defined by RCRA as “sludge from an air pollution control facility”—can contain heavy metals like lead, cadmium, and mercury, as well as other toxics, in concentrations great enough that it could be considered an air pollutant and hazardous waste.
Thus, prior to removing ash from the combustion chamber, most incinerator operators treat their fly ash by commingling it with bottom ash or a stabilizing agent such as lime to neutralize any toxic constituents. Before mixing the two ashes, however, it is standard practice for WTE facilities to remove metal scrap from bottom ash.
This scenario has become more complicated in recent years as questions have arisen regarding the so-called household waste exclusion under RCRA, which exempts incinerators that recover energy from burning only household waste and nonhazardous solid waste from commercial or industrial sources from the federal waste law’s Subtitle C, a stringent “cradle-to-grave” regulatory scheme for governing the treatment, storage, and disposal of hazardous waste. (The exclusion does not apply to WTE facilities that burn any hazardous wastes.)
While this may sound clear-cut, there have been varied interpretations of the household waste exclusion, particularly in terms of how and to whom the exclusion applies.
In May 1994, the U.S. Supreme Court attempted to clarify those issues, deciding in Chicago vs. Environmental Defense Fund that the household waste exclusion applies only to WTE facilities, not to their ash. More specifically, according to the court’s decision, incinerators that burn anything other than household waste (which essentially means all WTE incinerators since it’s highly unlikely a facility wouldn’t also handle office wastes or other nonhazardous commercial or industrial wastes) must test their ash to determine if it is hazardous and manage it accordingly.
Under federal law, that means performing the Toxicity Characteristic Leaching Procedure (TCLP), which tests a material’s potential to leach toxic constituents into soil, surface water, and groundwater. If incinerator ash tests hazardous under the TCLP, it must be managed as a Subtitle C hazardous waste. If, on the other hand, it passes the TCLP, it can be handled as a nonhazardous solid waste (governed by RCRA’s Subtitle D) and placed in a municipal solid waste landfill.
Regulatory Controversies
While the Chicago decision attempted to clarify the household waste exclusion, its ash-testing requirements raised another question: When should ash be tested for hazardous characteristics?
The EPA was left to answer this question, and in doing so considered three options: to require fly ash and bottom ash to be tested as separate waste streams, to permit fly and bottom ash to be commingled as a single waste stream prior to testing, or to defer administrative action until broader issues were decided under Phase II of the RCRA Land Disposal Restrictions.
The first option created the most controversy, stimulating what became known as the “four walls” debate. By requiring separate testing of fly ash and bottom ash, incineration representatives held, the EPA would be asserting its RCRA solid waste jurisdiction in an unprecedented context—to wit, within the four walls of the incinerator.
The key to the EPA’s jurisdiction under RCRA lies at the point at which a waste is generated, and this point is generally defined by an element of “discard.” Thus, the WTE industry representatives based their argument on the contention that ash residue is not discarded and therefore does not become a waste until it is removed from the facility.
In opposition, environmental groups asserted that fly ash and bottom ash are two separate waste streams created within the combustion chamber of the WTE facility. Thus, they held that fly ash and bottom ash should be tested and managed separately, as RCRA dictates for other separate waste streams.
The EPA sided with the incineration industry on this point, dropped the last option, and decided to allow WTE facilities to commingle fly and bottom ash prior to testing. This approach is consistent with prior EPA policy allowing hazardous wastes generated in a management process, like incineration, to be combined and managed as one waste stream.
The Recycling Connection
For recyclers of incinerator scrap, the EPA’s decision was important for two reasons.
First, requiring fly ash and bottom ash to be tested separately would have cost municipalities around $1 million to $3 million per incinerator in one-time capital expenditures to retrofit the facilities to separate the ash, plus millions more in testing and disposal costs. These costs could have prompted incinerators to increase the price of their scrap to recyclers, who would, in turn, have had to pass the added cost on to their consumers. The result could have been diminished demand for incinerator scrap—and potentially significant monetary repercussions for recyclers who handle significant tonnages of the material.
Second and equally important, any attempt by the EPA to regulate separate waste streams within the four walls of an industrial facility would trigger an immense amount of litigation. Although the application of the RCRA household waste exclusion makes the WTE incinerator scenario unique, an analogy can be easily made to the scrap recycling industry.
If the EPA were to establish a precedent for lawfully exerting its regulatory powers over manufacturing-like activities, what would stop it from attempting to regulate within the four walls of scrap recycling operations? Take the case of a shredder operation, for example. Hypothetically, the EPA would be able to assert its authority to make waste stream determinations before any residual materials—such as shredder fluff—were removed from the shredder itself and discarded.
On a similar note, a major concern of WTE industry representatives was a statement by an EPA official that once the door was open for the EPA to regulate within the four walls of an incinerator, far more than the two waste streams would be tested. In the WTE incineration context, the agency noted that “eight or nine other waste streams in the combustion unit could be subject to hazardous waste testing.” Apply this rationale to the scrap recycling industry, and a Pandora’s box of unwarranted regulatory scenarios would begin to unfold. Fortunately, the EPA has sided with the regulated community thus far on this issue and has declined to expand its regulatory authority in this manner.
Guidance for Recyclers
Recyclers aren’t completely home-free on this subject, however. Just as scrap recyclers who handle incinerator scrap are “downstream” from WTE facilities in terms of material flow, they could also be downstream in terms of environmental liability due to the presence of potentially hazardous ash on incinerator scrap. This could occur if hazardous waste or another form of regulated material—such as medical waste—is commingled with municipal solid waste before or during incineration at the WTE facility.
Nevertheless, the language of the RCRA household waste exclusion can be used to protect against such downstream liability. First, the specific language found in the exclusion should be incorporated into the purchase contract for incinerator scrap, specifying that incinerator scrap purchased is generated solely from the incineration of municipal solid waste. The contract should be clear that the waste has not been commingled with hazardous materials prior to or during incineration.
Second, recyclers should review any contractual requirements, notification provisions, or inspection procedures used by a WTE facility to ensure that hazardous wastes are not received or incinerated at the facility. If satisfactory, these safeguards should be noted and incorporated by reference into the contract.
In the absence of a formal purchase contract, recyclers can write a letter to the WTE facility confirming that it accepts only municipal solid waste for incineration and has adequate safeguards to ensure that it doesn’t accept or burn hazardous materials.
If an environmental liability dispute arises, recyclers could rely on either such contractual language or the confirming letter as a defense to an administrative action brought by the EPA or a state environmental agency, or to a civil action brought by private parties.
Recyclers should also take the following steps within their operations to prevent potential environmental liability related to incinerator scrap:
- All processing operations dealing with incinerator scrap should be segregated from other operations, and they should not be sited in an area containing pathways that lead to a “point source” as defined under the Clean Water Act. This is because recyclers who introduce incinerator ash into any “waters of the United States” via point source discharges may be required to modify their federal national pollution discharge elimination system permit, or state equivalent, at the time of renewal.
- Since ash is a potential pollutant under the Clean Water Act and can end up in storm water runoff, recyclers should manage the ash from incinerator scrap according to best management practices incorporated in their storm water pollution prevention plan.
- Recyclers should not keep ash from incinerator scrap on-site for more than 90 days. As downstream parties from WTE facilities, recyclers are only notified after the fact that a load of ash has failed the TCLP. RCRA, however, allows parties to store hazardous materials for up to 90 days without having a permit as a treatment, storage, or disposal facility. By removing incinerator ash from their plants within 90 days, therefore, recyclers avoid potential environmental compliance problems in this regard.
As these points indicate, recycling incinerator scrap is analogous to handling a porcupine: It can be done, but it must done correctly and with care.
Armed with a thorough knowledge of the incineration process, environmental rules governing WTE incinerators, and prudent handling and processing procedures, recyclers can safely—and profitably, many say—add incinerator scrap to their material mix. •
Like the mythical phoenix, incinerator scrap has risen from the ashes to become a significant and increasingly competitive recycling niche. Recyclers interested in this material, however, should know a few facts to avoid potential environmental liability.