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9441.1981(01) 

FOSSIL FUEL COMBUSTION WASTE EXCLUSION IN 261.4(B)(4), FUEL 

MIXTURES 

January 13, 1981 

Mr. Paul Emler, Jr. 

Chairman 

Utility Solid Waste Activities Group 

Suite 700 

1111 Nineteenth Street, N.W. 

Washington, D.C. 20036 

Dear Mr Emler: 

This is a response to your letter of October 10, 1980 to 

Administrator Costle, regarding the recent Solid Waste Disposal 

Act Amendments of 1980 and their relation to the electric utility 

industry. In your letter and its accompanying document, you 

discussed the specific amendments which address fossil fuel 

combustion wastes, and suggested interpretive language which EPA 

should adopt in carrying out the mandate of the amendments. You 

requested a meeting with our staff to make us more fully aware of 

the solid waste management practices of the electric utility 

industry, and to discuss the effect of the amendments on the 

utility solid waste study which EPA is currently conducting. 

I appreciated the opportunity to meet with you, in your 

capacity as chairman of the Utility Solid Waste Activities Group 

(USWAG), on November 21 to discuss your concerns. I am taking 

this occasion to share with you the most recent EPA thinking on 

the exclusion from our hazardous waste management regulations of 

waste generated by the combustion of fossil fuels, and to confirm 

certain agreements which were reached during our meeting. The 

language contained in this letter should provide you and your 

constituents with an adequate interpretation of the fossil fuel 

combustion waste exclusion in Section 261.4(b) (4) of our 

regulations. This letter is also being circulated to appropriate 

Agency personnel, such as our Regional Directors of Enforcement, 

for their information and use. We intend to issue in the Federal 

Register an official Regulations Interpretation Memorandum 

reflecting the policies articulated in this letter. 
 

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In our May 19, 1980 hazardous waste management regulations, 

we published an exclusion from Subtitle C regulation for those 

fossil fuel combustion wastes which were the subject of then 

pending Congressional amendments. The language of that exclusion 

in §261.4(b) (4) of our May 19 regulations is identical to 

pertinent language of Section 7 of the Solid Waste Disposal Act 

Amendments of 1980 (P.L. 96-482) which was enacted on October 21, 

1980 and which mandates that exclusion. Specifically, the 

exclusion language of our regulations provides that the following 

solid wastes are not hazardous wastes: 

 "Fly ash waste, bottom ash waste, slag waste, and flue gas 

 emission control waste generated primarily from the 

 combustion of coal or other fossil fuels." 

Residues from the Combustion of Fuel Mixtures 

The first point which you raise in your letter and your 

"Proposed RIM Language" is the interpretation of the term 

"primarily" used in this exclusion language. EPA believes that 

Congress intended the term "primarily" to mean that the fossil 

fuel is the predominant fuel in the fuel mix, i.e., more than 50 

percent of the fuel mix. (See Congressional Record, February 20, 

1980, p. H1103, remarks of Congressman Horton and p. H1102, 

remarks of Congressman Bevill.) Therefore, EPA is interpreting 

the exclusion of §261.4(b) (4) to include fly ash, bottom ash, 

boiler slag and flue gas emission control wastes (hereinafter 

referred to as "combustion wastes".) that are generated by the 

combustion of mixtures of fossil fuels and alternative fuels, 

provided that fossil fuels make up at least 50 percent of the 

fuel mix. 

This interpretation begs the question of whether the 

exclusion also extends to combustion wastes that result from the 

burning of mixtures of fossil fuels and hazardous wastes. We 

have limited data which indicates that spent solvents listed in 

§261.31 of our regulations, certain distillation residues listed 

in §261.32, waste oils that may be hazardous wastes by virtue of 

characteristics or the mixture rule, and other hazardous wastes 

are often burned as supplemental fuels--sometimes in 

proportionally small amounts but sometimes in significant amounts 

(comprising 10 percent or more of the fuel mix ratio)-- 

particularly in industrial boilers but sometimes in utility 

boilers. EPA is concerned about the human health and 
 

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environmental effect of the burning of these hazardous wastes: 

both the effect of emissions into the atmosphere and the effect 

of combustion residuals that would be contained in the fly ash, 

bottom ash, boiler slag and flue gas emission control wastes. 

We intend to address the first of these concerns in our 

future development of special requirements applicable to 

hazardous wastes that are beneficially used or legitimately 

recycled. In §261.6 of our May 19, 1980 regulations, we 

currently exempt from regulatory coverage hazardous wastes that 

are beneficially used or legitimately recycled, except that, 

where these wastes are listed as hazardous wastes or sludges, 

their storage or transportation prior to use or recycle is 

subject to our regulations. We clearly explained in the preamble 

to Part 261 of our May 19 regulations that we fully intend to 

eventually regulate the use and recycling of hazardous wastes 

and, in doing so, would probably, in most cases, develop special 

requirements that provide adequate protection of human health and 

the environment without unwarranted discouragement of resource 

conservation. Consequently, although the burning of hazardous 

waste as a fuel (a beneficial use assuming that the waste has a 

positive fuel value) is not now subject to our regulations 

(except as note above) it may well be subject to our regulation 

in the future. 

Our second concern with combustion of fuel mixtures is the 

one at focus in this interpretation. It must first be noted that 

we do not intend for §261.6 to provide an exemption from 

regulation for combustion wastes resulting from the burning of 

hazardous wastes in combination with fossil fuels; it only 

provides an exemption for the actual burning of hazardous wastes 

for recovery of fuel value. Thus, if these combustion wastes are 

exempted from our regulation, such exemption must be found 

through interpretation of §261.4(b) (4). Secondly, we note that 

although the pertinent language in Section 7 of the Solid Waste 

Disposal Act Amendments of 1980 and the related legislative 

history on this matter speak of allowing the burning of 

alternative fuel without precisely defining or delineating the 

types of alternative fuel, the only examples of alternative fuels 

used in the legislative history are refuse derived fuels. 

herefore, a literal reading of the legislative history might 

enable us to interpret the exclusion to include combustion wastes 

resulting from the burning of fossil fuels and other fuels, 

including hazardous wastes. However, since each of these 
 

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legislative comments was made in the context of refuse derived 

fuels or other non-hazardous alternate fuels, we do not believe 

the Congressional intent compels us to make such an 

interpretation if we have reason to believe that such combustion 

wastes are hazardous. 

Presently, we have little data on whether or to what extent 

combustion wastes are "contaminated" by the burning of fossil 

fuel/hazardous waste mixtures. The data we do have (e.g., 

burning of waste oils) suggests that the hazardous waste could 

contribute toxic heavy metal contaminants to such combustion 

wastes. When coal is the primary fuel, the amount of resulting 

contamination is probably in amounts that are not significantly 

different than the metals that would be contributed by the fossil 

fuel component of the fuel mixture. This may not be the case 

with oil and gas, where huge volumes of waste are not available 

to provide a dilution effect. We suspect that the other 

hazardous constituents of the hazardous wastes that typically 

would be burned as a fuel are either thermally destroyed or are 

emitted in the flue gas (and therefore are part of our first 

concern as discussed above). If these data and this presumption 

are true, then combustion wastes resulting from the burning of 

coal/hazardous waste mixtures should not be significantly 

different in composition than combustion wastes generated by the 

burning of coal alone. Because the Congress has seen fit to 

exclude the latter wastes from Subtitle C, pending more study, we 

feel compelled to provide the same exclusion to the former 

wastes. 

Accordingly, we will interpret the exclusion of §261.4(b) (4) 

to include fly ash, bottom ash, boiler slag and flue gas emission 

control wastes generated in the combustion of coal/hazardous 

waste mixtures provided that coal makes up more than 50 percent 

of the fuel mixture. 

We offer this interpretation with great reluctance and with 

the clear understanding it is subject to change, if and when data 

indicate that combustion wastes are significantly contaminated by 

the burning of hazardous wastes as fuel. We also offer this 

interpretation with the understanding, as discussed at our 

meeting of November 21, that the utility industry will work with 

us over the next several months to improve our data on this 

matter. We believe it is essential that we make a more informed 

judgement and possible reconsideration of our interpretation of 
 

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the exclusion as soon as possible and before completion of our 

longer-term study of utility waste which is proceeding. 

Accordingly, we would like you to provide to us all available 

data on the following questions by August 1, 1981: 

 1. What types of hazardous wastes are commonly burned as 

 fuels in utility boilers? In what quantity? In what 

 ration to fossil fuels? How often? what is their BTU 

 content? 

 2. Does the burning of these wastes contribute hazardous 

 constituents (see Appendix VIII of Part 261 of our 

 regulations) to any of the combustion wastes? If so, 

 what constituents, and in what amounts? How does the 

 composition of combustion wastes change when hazardous 

 wastes are burned? 

Co-disposal and Co-treatment 

The second issue raised in your letter was whether the 

exclusion extends to wastes produced in conjunction with the 

burning of fossil fuels which are co-disposed or co-treated with 

fly ash, bottom ash, boiler slag and flue gas emission control 

wastes. As examples of such wastes, you specifically mention 

boiler cleaning solutions, boiler blowdown, demineralizer 

regenerant, pyrites, cooling tower blowdown, or any "wastes of 

power plan origin whose co-treatment with fly ash, bottom ash, 

slag and flue gas emission control sludges is regulated under 

State-or-EPA-sanctioned management or treatment plans." 

The legislative history on this matter clearly indicates 

that the Congress intended that these other wastes be exempted 

from Subtitle C regulation provided that they are mixed with and 

co-disposed or co-treated with the combustion wastes and further 

provided that "there is no evidence of any substantial 

environmental danger from these mixtures." (See Congressional 

Record, February 20, 1980, p. H 1102, remarks of Congressman 

Bevill; also see remarks of Congressman Rahall, Congressional 

Records, February 20, 1980, p H1104.) 

We have very little data on the composition, character and 

quantity of these other associated wastes (those cited above), 

but the data we do have suggest that they are generated in small 

quantities relative to combustion wastes, at least when coal is 
 

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the fuel, and that they primarily contain the same heavy metal 

contaminants as the combustion wastes, although they may have a 

significantly different pH than the combustion wastes. These 

limited data therefore suggest that, when these other wastes are 

mixed with and co-disposed or co-treated with the much larger 

quantities of combustion wastes, their composition and character 

are "masked" by the combustion and character of the combustion 

wastes; that is, they do not significantly alter the hazardous 

character, if any, of the combustion wastes. 

Given this information base and given the absence of 

definitive information indicating that these other wastes do pose 

a "substantial danger" to human health or the environment, we 

believe it is appropriate, in the light of Congressional intent, 

to interpret the §261.4(b) (4) exclusion to include other wastes 

that are generated in conjunction with the burning of fossil 

fuels and mixed with and co-disposed or co-treated with fly ash, 

bottom ash, boiler slag and flue gas emission control wastes. 

We offer this interpretation with some reluctance because it 

is made in the absence of definitive information about the 

hazardous properties of these other wastes or their mixtures with 

combustion wastes. We therefore believe it is imperative that we 

proceed to collect all available data on this matter within the 

next several months and reconsider this interpretation when these 

data are assessed. Toward that end and consistent with the 

discussion at our meeting of November 21, we are asking that you 

assist us in collecting these data. Specifically, we ask that 

ou collect and submit by August 1, 1981, any available data on 

the following questions: 

 1. What are the "other" wastes which are commonly mixed 

 with and co-disposed or co-treated with fly ash, bottom 

 ash, boiler slag or flue gas emission control wastes? 

 What are their physical (e.g., sludge or liquid) and 

 chemical properties? Are they hazardous wastes in 

 accordance with Part 261? 

 2. What are the co-disposal or co-treatment methods 

 employed? 

 3. How often are these wastes generated? In what 

 quantities are they generated? Are they commonly 

 treated in any way before being co-disposed? 
 

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 4. Does the industry possess any data on the environmental 

 effects of co-disposing of these wastes? Groundwater 

 monitoring data? What are the results? 

The interpretation on other associated wastes provided in 

this letter is limited to wastes that are generated in 

conjunction with the burning of fossil fuels. We do not intend 

to exempt hazardous wastes that are generated by activities that 

are not directly associated with fossil fuel combustion, steam 

generation or water cooling processes. Thus, for example, the 

§261.4(b) (4) exclusion does not cover pesticides or herbicide 

wastes; spent solvents, waste oils or other wastes that might be 

generated in construction or maintenance activities typically 

carried out at utility and industrial plants; or any of the 

commercial chemicals listed in §261.33 which are discarded or 

intended to be discarded and therefore are hazardous wastes. 

Further, the exclusion does not cover any of the hazardous wastes 

listed in §§261.31 or 261.32 of our regulations. None of these 

listed wastes were mentioned in your letter or our discussions. 

The interpretation on other wastes is also limited to wastes 

that traditionally have been and which actually are mixed with 

and co-disposed or co-treated with combustion wastes. If any of 

these other wastes (e.g., boiler cleaning solutions, boiler 

blowdown, demineralizer regenerant, pyrites and cooling tower 

blowdown) are segregated and disposed of or treated separately 

from combustion wastes and they are hazardous wastes, they are 

not covered by the exclusion. In the same vein, the exclusion 

does not cover other wastes where there are not combustion wastes 

(or relatively small amounts of combustion wastes) with which 

they might be mixed and co-disposed or co-treated--a situation 

which might prevail where natural gas or oil is the principal 

fossil fuel being used. Therefore, this interpretation of the 

exclusion applies only where coal is the primary fuel. We feel 

this is a legitimate interpretation of Congressional intent, 

wherein the argument of little potential environmental hazard, 

primarily due to the dilution factor, is clearly based upon codisposal or co-treatment with the huge volumes of wastes 

generated during coal combustion. 

EPA Utility Waste Study 

The groups of questions raised above bring us to the subject 

which you address concerning the study of utility waste 
 

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management which EPA is conducting. We agree that the study, as 

currently being conducted, does not focus on the matters 

discussed in this letter. We would, however, like to address 

these matters and include them in our report to Congress, to the 

extent possible. To accomplish this, we plan to meet in the very 

near future with our contractor, Arthur D. Little, Inc., to 

discuss what studies may need to be carried out in addition to 

their currently planned activities under the contract. The 

inputs of your organization could be quite useful in this effort. 

It may be impossible, however, to modify our present study to 

include a detailed investigation of all of the issues discussed 

above. 

Notwithstanding, we would like to address the matters 

discussed in this letter within a shorter time frame--during the 

next six months. Based on our meeting of November 21, it is my 

understanding that the utility industry, working closely with 

EPA, is willing to develop data on the questions put forth above. 

We agreed that, as a first step, USWAG will prepare a study 

outline designed to obtain these data. EPA staff and industry 

representatives designated by your organization will then 

mutually review the information needs. The data collection 

effort will then follow. Finally, data and analyses will be 

presented to EPA for review. This will enable us to reconsider 

the interpretation provided in this letter and make any changes 

deemed necessary. Therefore, I would appreciate it if you would 

designate a technical representative as USWAG's contact person 

for this coordinated data collection effort. 

In the meantime, and pending completion of this effort, EPA 

will interpret 40 CFR §261.4(b) (4) to mean that the following 

solid wastes are not hazardous wastes: 

 (a) Fly ash, bottom ash, boiler slag and flue gas emission 

 control wastes resulting from (1) the combustion solely 

 of coal, oil, or natural gas, (2) the combustion of any 

 mixture of these fossil fuels, or (3) the combustion of 

 any mixture of coal and other fuels, up to a 50 percent 

 mixture of such other fuels. 

 (b) Wastes produced in conjunction with the combustion of 

 fossil fuels, which are necessarily associated with the 

 production of energy, and which traditionally have 

 been, and which actually are, mixed with and co- 
 

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 disposed or co-treated with fly ash, bottom ash, boiler 

 slag, or flue gas emission control wastes from coal 

 combustion. 

This provision includes, but is not limited to the following 

wastes: 

 (1) boiler cleaning solutions, 

 (2) boiler blowdown, 

 (3) demineralizer regenerant, 

 (4) pyrites, and 

 (5) cooling tower blowdown. 

I am hopeful that our future research activities together 

will prove fruitful and that these issues can be rapidly 

resolved. I have designated Ms. Penelope Hansen of my staff as 

the EPA point of contact for this effort. You may reach her at 

(202) 755-9206. 

Sincerely yours, 

Gary N. Dietrich 

Associate Deputy Assistant Administrator 

for Solid Waste