August 21, 2015

(Via email: johnson.barnes@epa.gov)

Mr. Barnes Johnson, Director

Office of Resource Conservation and Recovery

Office of Solid Waste and Emergency Response

U.S. Environmental Protection Agency

1200 Pennsylvania Ave., N.W.

Mail Code 5301P

Washington, DC 20460

Re: Supplemental Information Regarding Petition for Determination Identifying NonHazardous Secondary Treated Wood Biomass as a Non-Waste under 40 C.F.R. §241.4(a)

Dear Mr. Johnson:

On April 3, 2013, the Treated Wood Council (TWC) submitted a petition under 40 C.F.R.

§241.4(b), seeking a determination that certain non-hazardous secondary treated wood biomass

materials are, as a category, not a waste. Among those materials were rail ties treated with

copper naphthenate (CuN), dual-treated CuN-borate (CuNB), and dual-treated creosote-borate

(CB) formulations. TWC provided data showing that these materials meet the legitimacy criteria

and are processed to produce a valuable fuel, consistent with the standards EPA set forth in its

final rule on Non-Hazardous Secondary Materials (NHSM), 78 Fed. Reg. 9112 (Feb. 7, 2013).

As part of EPA’s review of this petition, TWC responded to questions and provided

additional data over the course of the next two years, including submissions on May 20, 2013,

December 4, 2013, and May 28, 2014, and met with EPA several times, receiving assurances

each time that the data were useful and complete, and that TWC’s petition would be the subject

of a proposed rule in the near future. On April 14, 2014, EPA proposed a rule recommending the

addition of three types of secondary materials to those already categorically determined to be

non-waste fuels in EPA’s February 2013 final rule. The proposed new categories were:

construction and demolition debris, paper recycling residuals, and creosote-treated rail ties.1In

1 Additions to List of Section 241.4 Categorical Non-Waste Fuels; Proposed Rule, 79 Fed. Reg. 21006 (Apr. 14,

2014) (Proposed Rule).

1101 K Street, NW

Suite 700

Washington, DC 20005

Phone: (202) 641-5427

Fax: (202) 463-2059
2

support of the part of the rule relating to rail ties, EPA relied on data provided by TWC, which

the Agency reviewed and clearly found credible.2

In the Proposed Rule, EPA specifically directed that comments be submitted only on

creosote-treated rail ties, 79 Fed. Reg. at 21028. The notice stated that other treated wood

materials identified in the TWC petition were under active review, and that if that review

“supports a categorical listing of one or more of these other treated wood materials, the Agency

would propose those materials in a future rulemaking,” id. at 21010. Despite EPA’s admonition,

commenters urged EPA to expand the categorical non-waste determination to include CB-dual

treated and CuN-treated ties. For example, one commenter noted that both these materials are

regarded as valuable commodity fuels and pointed out data showing CuN ties would not add

contaminants at levels that exceed those in comparable traditional fuels.3

The Proposed Rule is now in final form and currently at the Office of Management and

Budget for interagency review.4 At TWC’s July 20, 2015, meeting with you and Agency staff,

staff reported that on the basis of comments submitted in the creosote rulemaking, EPA was

planning to take favorable action to add CB dual-treated ties to the categorical non-waste

determination for creosote-treated rail ties. However, in an abrupt reversal of its longstanding

previous position, EPA staff said that TWC’s petition, covering both CuN- and CuNB-treated

ties as well as other materials included in the petition, was too broad and would be denied in an

“all or nothing” approach under which none of the materials could move forward unless all

satisfied EPA’s judgment. This approach is in conflict not only with EPA’s previous statements

to TWC about how it would proceed, but also with EPA’s stated intention in the Proposed Rule,

that if its review “supports a categorical listing of one or more of these other treated wood

materials, the Agency would propose those materials in a future rulemaking.”

As commenters on the Proposed Rule noted,5and as a recent survey conducted by the

Railway Tie Association, Association of American Railroads, and American Short Line and

Regional Railroads Association6reinforces, CuNB-treated rail ties are increasingly being used as

an alternative to creosote- and CB-treated ties. As the survey also documents, in responses from

all seven Class 1 railroads and an additional large short line holding company, railroads said that

the ability to reuse ties as a valuable fuel is an important consideration in rail tie purchasing

decisions.7EPA appears motivated to move quickly in response to these market realities in

adding CB-treated ties as a categorical non-waste, to avoid their deselection in favor of

alternatives that involve greater fossil-fuel consumption and consequently higher environmental

2

See, e.g., 79 Fed. Reg. at 21022 n.80, 21023 n.88.

3 Comments of DTE Energy Services, EPA-HQ-RCRA-2013-0110-0083, at 10 (June 13, 2014).

4

See http://www.reginfo.gov/public/do/eAgendaViewRule?pubId=201504&RIN=2050-AG74.

5

See, e.g., Comments of the Association of American Railroads , EPA-HQ-RCRA-2013-0110-0077(June 13, 2014),

Comments of DTE Energy Services, EPA-HQ-RCRA-2013-0110-0083 (June 13, 2014).

6

Stephen T. Smith, 2014 Railway Ties Survey, at 3 (April 6, 2015, revised Aug. 12, 2015), available at

http://www.rta.org/assets/docs/RTASponsoredResearch/Environmental/ties%20survey%20report%2012aug20151.p

df. CuNB ties accounted for 1.7% of the market in 2013, or 249,612 new rail ties.

7

Id. at 3 n.4.
3

and greenhouse gas (GHG) emissions.8These adverse consequences apply equally to the

railroads’ purchasing decisions regarding CuN- and CuNB-treated ties and require urgent action

on these materials that is consistent with a proposed categorical determination for CB-treated

ties.

For the reasons discussed below, TWC calls upon EPA to fulfill its stated intention to act

on materials for which the record supports a categorical non-waste listing, and include CuN- and

CuNB-treated rail ties at the same time as it moves forward on CB-treated rail ties. TWC is

prepared to discuss with EPA as a separate matter the remaining secondary materials covered by

the April 3, 2013 petition, and appreciates your commitment at the July 20 meeting to review

additional information on the materials in the TWC petition on a priority basis.

CuN- and CuNB-Treated Ties Meet EPA’s Requirements for a Categorical Non-Waste

Determination.

The requirements for a categorical non-waste determination in 40 C.F.R. §241.3(d)(1)

are: (1) the nonhazardous secondary material (NHSM) is managed as a valuable commodity; (2)

the NHSM must have a meaningful heating value and be used as a fuel in a combustion unit that

recovers energy; and (3) the NHSM must contain contaminants at levels comparable in

concentration to or lower than those in traditional fuels that the combustion unit is designed to

burn. In multiple submissions to the record, with data comparable or even identical to that relied

on by EPA in justifying a proposed categorical determination for creosote-treated rail ties, and

presumably CB-treated ties, TWC has provided ample data to satisfy these requirements for

CuN- and CuNB-treated ties.9 Despite this record, at the July 20 meeting, EPA staff raised

several issues, which are addressed in turn below.

8 As TWC and numerous commenters have repeatedly explained, misclassification of legitimate biomass fuels such

as CuN- and CuNB-treated ties will force their diversion to landfills and increase reliance on fossil fuels instead.

This outcome is doubly adverse in terms of GHG emissions: (1) instead of the well-recognized net zero carbon

dioxide (CO2) emissions associated with biomass energy recovery, substitution of fossil fuels will result in

substantially increased CO2 emissions; and (2) greater landfill biomass volume translates to higher emissions of

methane, a GHG that has 28-36 times the potency of CO2, based on the most recent International Panel on Climate

Change (IPCC) assessment report, as cited in EPA’s Emission Guidelines and Compliance Times for Municipal

Solid Waste Landfills, Proposed Rule, 80 Fed. Reg. ____, prepublication version available at

http://www.epa.gov/ttn/atw/landfill/20150814egfr.pdf, at 27 and n.5 (Aug. 14, 2015). Concerns about methane

emissions from landfills are serious enough that EPA recently proposed stricter methane controls for landfills (id.),

and the federal government has developed a national strategy to reduce methane emissions by 17% by 2020.

Executive Office of the President, “Climate Action Plan Strategy to Reduce Methane Emissions” (March 2014),

https://www.whitehouse.gov/sites/default/files/strategy_to_reduce_methane_emissions_2014-03-28_final.pdf. The

methane-increasing consequences of EPA’s unwarranted consignment to landfills of a growing share of the 14.9

million rail ties currently purchased every year are sharply at odds with national policy.

9 The second and third requirements are discussed more fully below. Regarding the first requirement, TWC has

submitted substantial information showing that the materials covered by its petition are managed as valuable

commodities. See TWC Petition for Determination Identifying Non-Hazardous Secondary Treated Wood Biomass

as a Non-Waste under 40 C.F.R. §241.4(a), at 3-5 (April 3, 2013) (TWC Petition). Specifically with respect to

CuN- and CuNB-treated ties, Attachment 3 to the TWC Petition is a Statement by Jeff Parrett, Vice President of

Wheeler Lumber, L.L.C., which describes the growing use of those materials as an alternative to creosote, and their

reuse for energy production in the same manner as creosote. A copy of Mr. Parrett’s Statement is attached to this

letter for convenience as Attachment 1. In addition, the August 15, 2015 letter from Ronald Silverthorn, Manager of
4

1. TWC’s petition covers eight types of NHSM, and EPA is uncomfortable with the

breadth of these combustion scenarios.

TWC submits that it has met EPA’s requirements for all of the NHSM covered by its

petition, but is willing to approach the materials in its petition in a disaggregated way. Because

of the strength of the data in the record on CuN- and CuNB-treated ties, and their marketplace

importance as alternatives to materials that are moving forward for determinations as categorical

nonwastes, TWC urges EPA to consider these materials as a first priority. TWC will separately

address with EPA the specifics of the other NSHM in its petition.

2. EPA needs additional sample data on CuN- and CuNB-treated ties to examine the

range of variability of contaminants in discrete samples.

TWC has provided test data on CuN- and CuNB-treated ties, along with contaminant

comparisons for creosote, creosote-borate, and untreated wood.10 However, to provide further

data for EPA’s review, TWC has undertaken additional testing, and these laboratory results will

be provided as soon as they are available, which is expected to be within the next two weeks.

3. EPA would like to see data on post-processing samples of CuN and CuNB ties. In

particular, EPA seeks data on BTU value, moisture content and possible synergistic chemical

changes when CuN and CuNB materials are processed with creosote and CB ties.

BTU Value. TWC has previously submitted data showing the high BTU per pound

values of CuN- and CuNB-treated wood (7,107), compared to creosote (7,936) and untreated

wood (5,667).11 Consistent with TWC’s data, EPA’s Proposed Rule cites a BTU per pound

value for clean wood of 3,440-5,150, based on EPA emissions data.12 For creosote, EPA notes

without citation that it is relying on “recent information that the heating value of processed

CTRTs [creosote-treated rail ties] ranges from 6,000-8,000 BTU.”13 TWC also provided dataderived calculations of CuN (7,100) and CuNB (7,200) fuel BTU values, in its May 28, 2014

supplemental submission to EPA.14 EPA’s Proposed Rule cites its 2011 final rule to the effect

that BTU values above 5,000 per pound are considered to have meaningful heating value.15

These data should be sufficient, but in order to satisfy EPA’s further requests, TWC has

Resource Recovery for DTE Stoneman, LLC, describes how DTE manages used CuN- and CuNB-treated ties in the

same way as creosote- and CB-treated ties, as all four of these types of rail ties are managed, processed and used for

energy recovery. The letter is attached as Attachment 2.

10 See Letter from Jeffrey T. Miller TWC, to George Faison, EPA (Dec. 4, 2013) Tables 1, 3, and 4; TWC Petition,

Tables I, III, and IV.

11 See Comments of Treated Wood Council, EPA Docket EPA-HQ-RCRA-2008-0329-0772, at Table 1 (Aug. 2,

2010).

12 Proposed Rule, 79 Fed. Reg. at 21024 n.94.

13 Id. at 21024.

14 TWC, “Estimates of BTU Value and Quantity of Treated Wood Biomass Recycled for Energy” (May 28, 2014),

submitted to EPA during May 28, 2014 meeting with Barnes Johnson, George Faison and staff, and transmitted to

George Faison via electronic mail by Jeffrey T. Miller, TWC, on May 30, 2014.

15 79 Fed. Reg. at 21024.
5

undertaken additional sampling of the BTU value of post-processing CuN and CuNB ties. TWC

expects to submit these results within the next two weeks.

Moisture Content. TWC’s April 3, 2013 Petition noted that treated wood is drier than

virgin wood or milling by-products, such as chips or bark, with a moisture content of

approximately 20 percent, compared to virgin wood’s 50 percent.16 TWC previously submitted

data supporting these values.17 It does not appear that moisture content is a factor on which EPA

relied in its Proposed Rule, but TWC will submit additional, post-processing data on moisture

content shortly.

Hypothesis of Post-Processing Synergistic Changes. Because the processing that

recycled rail ties undergo is physical and not chemical,18 EPA’s concern about the possibility of

synergistic chemical changes from combining CuN or CuNB with creosote and CB ties must

relate to some theoretical potential for a differing chemical reaction once a combined fuel is

introduced into a boiler. TWC has conducted laboratory tests to address EPA’s request for

information on potential synergistic changes. The results are attached as Attachments 3 and 4.

Attachment 3 is a technical report on the assessment of chemical reaction, including

analysis, of samples of solutions of creosote, both with and without borate, and CuN, conducted

by analytical chemist Karson Lurie. Ms. Lurie’s Statement discusses the steps she followed in

her laboratory work and her observation that, when solutions of these chemicals are combined,

no chemical reaction occurred, disproving a hypothesis of negative synergistic reaction.

With similar results using treated wood in extensive and state-of-the-art laboratory tests

of separate and mixed post-processing fuel samples of creosote- and CuNB-treated used rail ties

conducted at the University of Tennessee Center for Renewable Carbon, Prof. Nicole Labbé and

researcher Dr. Pyoungchung Kim exposed separate and mixed samples to combustion

temperatures comparable to those of commercial boilers. The results show that there is no

chemical interaction between creosote and CuNB-treated wood when processed together and

combusted. As Drs. Labbé and Kim’s report concludes: “The chemicals produced from the

wood itself, creosote-treated wood, and CuNB treated wood were observed in samples tested

separately. The same chemicals were also observed in a blended sample (containing wood

treated with creosote and wood treated with CuNB), and no new additional chemicals were

observed due to the blending. These results confirm that there is no chemical interaction

between creosote and CuNB treated wood when processed together as a boiler fuel.”19

Accordingly, it appears there is no basis for concern regarding potential post-processing

synergistic changes relating to CuN- or CuNB-treated rail ties.

4. EPA seeks additional information on how CuN- and CuNB-treated ties are processed.

16 See TWC Petition at 5.

17 See Comments of Treated Wood Council, EPA-HQ-RCRA-2008-0329-0772, at Table 1.

18 See 79 Fed. Reg. at 21024.

19 Attachment 4 at 3.
6

CB, CuN and CuNB treatments for rail ties are relatively new, compared to creosote, and

given the long initial useful life of crossties, large volumes of these ties are still in place and not

yet transitioned into their secondary use as fuel. But the use of these alternatives is of growing

interest to the railroads, as documented in the 2014 Railway Ties Survey.20 As Jeff Parrett, Vice

President of Wheeler Lumber, LLC, explained in a Statement previously submitted for the

record: “Copper naphthenate has...more recently found a growing market acceptance as a

treatment product on its own or with borate for railroad ties. Wheeler Lumber currently

specifies, and treats with Copper Naphthenate for the state of New York, many other state DOTs,

USFS, Railroads, along with many other customers nationwide.”21

At least one electricity-generating facility – DTE Stoneman, LLC, of Cassville,

Wisconsin – is specifically permitted to use CuN- and CuNB-derived fuel, and its Manager of

Resource Recovery has described how that facility manages the four types of ties it receives

through contracts with the railroads:

Through contracts with the railroads, DTE (WI) receives ties of

four specific chemistries, namely, creosote, copper naphthenate

and both of these dual-treated with borates. DTE does not

separate these chemically-treated ties, as they are virtually

indistinguishable from each other after use and DTE’s permit

allows all of them to be combusted as a mixture. DTE does not

accept wood products treated with pentachlorophenol or arsenical

preservatives. Whole ties arrive by railcar. DTE contracts out all

shredding/chipping operations, which are done either on-site or at

the contractor’s facility. Metal is removed and ties are shredded to

a mulch-like consistency prior to burning. All ties are handled and

processed in the same manner for size reduction and metal

removal, and become part of the final mixed fuel.22

More broadly, many commercial boilers and co-gen facilities are permitted to burn

“railroad ties” generally, and the attached letters from Josh Wagner of National Salvage23 and

T.C. Taylor of T.C. Taylor Co., Ltd.,24make clear that if these alternative secondary materials

were classified as non-waste fuels, they would be processed in the same way as creosote-treated

20 See note 6 above.

21 Statement of Jeff Parrett, Wheeler Lumber, LLC (March 26, 2013), Attachment 3 to TWC Petition and

Attachment 1 to this letter. Mr. Parrett added: “Like other forms of treated wood such as those using creosote,

copper Naphthenate treated wood ties are desirable as fuel to electricity generators and others because of these

materials’ high BTU value, attractive economics, and superior greenhouse gas characteristics compared to fossil fuel

that would otherwise be burned for energy generation if these valued secondary materials were not available.”

22 Letter from Ronald Silverthorn to Dr. Jeff Lloyd (Aug. 15, 2015), Attachment 2.

23 Letter from Josh Wagner, National Salvage & Service Corp., to Jeff Miller, TWC (Aug. 10, 2015) (attached as

Attachment 5).

24 Letter from T. C. Taylor, T. C. Taylor Co., Ltd., to P. H. Haroz, Conversion Technology, Inc. (Aug. 11, 2015)

(attached as Attachment 6).
7

rail ties currently are, which EPA has concluded meets the definition of processing under 40

C.F.R. §241.2.25

5. While a commenter sought to add CB ties to the proposed categorical determination

for creosote ties, EPA claims no parallel request was submitted for CuN- and CuNB-treated ties.

This assertion is not factually correct. As noted above, one commenter specifically

requested that EPA add CuN- and CuNB-treated ties to the categorical determination for

creosote- and CB-treated ties immediately.26 Other commenters supported the addition of CuNand CuNB-treated ties, relying on their understanding that EPA was moving forward in a timely

way on TWC’s petition.27 Given that EPA specifically discouraged comments on materials other

than those in the Proposed Rule, it is surprising that any commenters at all urged EPA to add CB

and CuN ties, and it would be disingenuous for EPA to argue that it shows a lack of interest if

only a few made such a request. Beyond that, the Association of American Railroads and

Railway Tie Association have now urged EPA to proceed expeditiously to act favorably on CuNand CuNB-treated rail ties,28 and TWC supports these requests.

Conclusion

For the reasons explained above, TWC urges EPA to act promptly to determine that CB-,

CuN- and CuNB-treated rail ties are non-waste fuels under 40 C.F.R. §241.4(a). These materials

meet the standards EPA has established for a categorical non-waste determination. While, as the

statements of industry observers and the 2014 Railroad Ties Survey indicate, railroad interest is

increasing in purchasing CuN- and CuNB-treated rail ties (as well as CB ties), in the words of

the Association of American Railroads, EPA’s “failure to act expeditiously on crossties treated

with copper naphthenate or copper naphthenate and borate could impact current railroad

purchasing decisions” and produce an “environmentally counterproductive” outcome.29

We would be pleased to meet with you or respond to any questions you may have.

Respectfully submitted,

Jeffrey T. Miller

President & Executive Director

Cc: George Faison

Attachments (6)

25 79 Fed. Reg. at 21023.

26 Comments of DTE EnergyServices, EPA-HQ-RCRA-2013-0110-0083, at 10 (June 13, 2014).

27 See Comments of the Association of American Railroads, EPA-HQ-RCRA-2013-0110-0077, at 3 (June 13, 2014).

28 See Letter from Michael J. Rush, Association of American Railroads, to Barnes Johnson, EPA (Aug. 14, 2015);

letter from James C. Gauntt, Executive Director, Railway Tie Association, to Barnes Johnson, EPA (Aug. 20, 2015).

29 Letter from Michael J. Rush, at 2.

DTEStoneman, LLC

414 South Main Street, Suite 600

Ann Arbor, Michigan 48104

(734) 302-4800 Fax (734) 302-4802

August 15, 2015

Dr. Jeff Lloyd

Vice President Research & Development

Nisus Corporation

100 Nisus Dr. Rockford, TN 37853

Dear Mr. Lloyd,

Per our discussion here is the information about how we handle railroad cross ties at out DTE Stoneman Facility located in Cassville

Wisconsin.

Through contracts with the railroads, DTE (WI) receives ties of four specific chemistries, namely, creosote, copper naphthenate and

both of these dual-treated with borates. DTE does not separate these chemically-treated ties, as they are virtually indistinguishable

from each other after use and DTE’s permit allows all of them to be combusted as a mixture. DTE does not accept wood products

treated with pentachlorophenol or arsenical preservatives. Whole ties arrive by railcar. DTE contracts out all shredding/chipping

operations, which are done either on-site or at the contractor’s facility. Metal is removed and ties are shredded to a mulch-like

consistency prior to burning. All ties are handled and processed in the same manner for size reduction and metal removal, and

become part of the final mixed fuel.

Please let me know if I can be of any other assistance to you.

Sincerely,

Ronald Silverthorn

Manager of Resource Recovery

DTE Stoneman
STATEMENT OF NO REACTIVITY BETWEEN CREOSOTE, COPPER NAPHTHENATE 

AND BORATE SOUTIONS 

I, Karson Lurie, make the following statement in support of the Treated Wood Council’s August 

2015 Letter on Supplemental Information Regarding Petition Identifying Non-Hazardous 

Secondary Treated Wood Biomass as a Non-Waste under 40 C.F.R. §241.4(a). 

1. My title is: Analytical Chemist, Nisus Corporation, Rockford, TN. I received a B.S. degree in 

Chemistry from the University of Tennessee. I have extensive chemistry and laboratory 

experience with a primary focus on analytical techniques involved with wood analysis and 

chemical synthesis. My professional experience includes quality control of pesticide 

formulations using standardized chemistry analytical methods, formulating new products for 

treating wood, and improving current products by developing new treatment methods and their 

physical properties. 

2. I was asked by Dr. Jeff Lloyd of Nisus Corporation to test samples of creosote, both with and 

without borate additives, and copper naphthenate (QNAPTM) work solutions to determine QNAP 

and creosote chemical compatibility, as follows: 

a) Nisus QNAP2 (2% Cu content) formulated in a #2-diesel solution was diluted to an 

estimated 1% work solution strength in a 1:1 weight dilution and analyzed for exact % 

copper (Cu) content via an automated complexometric (EDTA) titration, equivalent to 

AWPA Standard A88. The prepared lab batch was assayed as 1.2% Cu. 

b) pH of the prepared QNAP solution and two creosote samples was determined, the latter 

being creosote alone and creosote containing a small (<1%) amount of borate. The pH of 

all 3 individual solutions was between 5.6 and 6.1. 

c) Initial photos were taken of each solution prior to blending and physical characteristics of 

each sample were noted. Both creosote blends are coffee brown in color with tiny micro 

brown particulates. The QNAP work solution is blue-green with no particulates. 

d) The initial temperature of all 3 beakers was measured and recorded. All initial 

temperatures were 22-23°C
e) 50 g of QNAP work solution was measured into a 140ml glass beaker. While stirring the 

QNAP solution on a stir-plate, 50 g of creosote solution was added to the beaker to give a 

1:1 w:w blend by weight. This step was then repeated for the other creosote blend 

containing borate additives. Once homogenous, the beakers stirred for an additional 10 

minutes to wait for any signs of a reaction. 

f) No visible signs of reaction were noted, and the final temperature of each beaker 

confirmed no endothermic or exothermic reaction had occurred. The final pH was also 

measured to note any changes between the mix and the individual components. The final 

pH of the each blend was between 5.4 and 5.6 with the slightly higher pH belonging to 

the sample containing borate additives, which are known buffering agents. 

g) The final Cu content of each blend was also assayed to compare with the concentration 

expected from a 1:1 w:w dilution of QNAP with Cu-free creosote samples. A manual 

colorimetric titration was used since the small fines in the creosote interfered with autotitration. The samples contained 0.61% for the QNAP-creosote blend and 0.56% for the 

QNAP-creosote blend containing borates. Both of these values are within the method 

error range for half of the original 1.20% Cu value, suggesting no reaction with the active 

ingredients occurred and all copper remained in solution upon mixing. 

h) A final photo was taken of each mixed solution. 

3. My conclusion from the test is that QNAP is completely compatible with creosote, and the 

two materials are unreactive with each other. 

Karson Lurie 

Dated: August 19, 2015 
Assessment of chemical interaction of mixed railroad tie fuel containing 

wood treated with creosote and copper naphthenate with borate. 

August 20, 2015 

Report prepared by: 

Pyoungchung Kim (pkim1@utk.edu) and Nicole Labbé (nlabbe@utk.edu); Center for Renewable Carbon, 

The University of Tennessee 

1. Summary 

Railroad tie samples treated with creosote or copper naphthenate with borate (CuNB) 

were tested at elevated temperatures to determine the chemicals present and those released at 

combustion temperatures. The chemicals produced from the wood itself, creosote-treated wood, 

and CuNB treated wood were observed in samples tested separately. The same chemicals were 

also observed in a blended sample (containing wood treated with creosote and wood treated with 

CuNB), and no new additional chemicals were observed due to the blending. These results 

confirm that there is no chemical interaction between creosote and CuNB treated wood when 

processed together as a boiler fuel. 

2. Material and methods 

2.1. Materials 

Used railroad wood ties treated with creosote (red oak) or CuNB (sweetgum) were 

obtained from Nisus Corp. (Rockford, TN, USA). The wood ties were ground into less than 0.4 

mm particle sizes with a knife mill before testing. In addition to testing separately, the two 

samples were mixed by weight ratio of 1:1 (wt. %) and pyrolyzed and the vapor composition 

analyzed. 

2.2. Methods 

Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was used to thermally 

decompose the used wood tie samples and the mixture at 450 °C for 12 seconds. A Perkin Elmer 

Clarus 680 Gas Chromatograph, coupled with a Clarus SQ 8C Mass Spectrometer and fitted with 

2506 Jacob Drive • Knoxville, TN 37996 • P 865.946.1130 • F 865.946.1109 • renewablecarbon.tennessee.edu
a micro-pyrolyzer and an autosampler that loads samples for pyrolysis (Frontier EGA/Py-3030 

D), was used to perform the analysis. Each sample pan was layered 0.4 mg of material and 

dropped via the autosampler into the pyrolysis furnace that was directly attached to the injection 

port of a GC/MS instrument. The vapor produced from the pyrolysis was swept into the injector 

port by the GC carrier gas that passes through the furnace, separated by an Elite 1701 MS 

capillary column (60 m x 0.25 mm ID x 0.25 micron film thickness), and analyzed using a MS 

(source temperature 270 °C, 70 eV electron ionization). 

3. Results and discussion 

The creosote- and CuNB-treated wood samples and their mixture by weight ratio of 1:1 

(wt. %) were thermally treated at 450 °C for 12 seconds. Figure 1 shows that the pyrograms of 

the mixed sample contained all chromatographic peaks including creosote and alkane 

hydrocarbons that are detected separately in the pyrograms of the creosote- and CuNB-treated 

samples, and wood-decomposition components from both red oak and sweetgum. 

Figure 2 shows the fragments of m/z values that represent mass divided by charge number. The 

m/z value is often considered to be the fragment mass of compounds. For example, the fragment 

mass values (m/z) of 76 and 71 represent creosote- and alkane hydrocarbons-derived 

compounds, respectively. Figure 2a shows the fragment m/z value of 76 representing creosote 

compounds found in creosote-treated red oak and the mixture. Creosote compounds, such as 

naphthalene, biphenyl, acenaphthene, phenanthrene, anthracene, fluoranthene and pyrene, were 

detected in both samples and did not disappear in the mixed sample. Figure 2b showed the 

fragment m/z value of 71 representing alkane hydrocarbons present in CuNB-treated sweetgum 

and the mixture. Alkane hydrocarbons were also detected in both samples and did not disappear 

in the mixture sample. It was also found that no new or additional peaks were produced in the 

mixed samples. This result confirms that both chemicals, creosote and alkane hydrocarbons, do 

not react with each other during pyrolysis to produce new chemicals or otherwise change the fuel 

materials. It can be concluded that mixed fuels containing wood, with creosote and borate, 

copper naphthenate or copper naphthenate with borate or mixtures thereof, can be combusted as 

fuel in the same way as creosote treated wood alone, without chemical interaction or any 

potential for negative interaction. 
Figure 1. Py-GC/MS pyrograms produced from treated wood tie samples including creosoteand CuNB-treated ties, and mixed sample (1:1 wt. %) via fast pyrolysis at 450 °C for 12s. 
Figure 2. Fragments of m/z values 76 for creosote and 71 for alkane hydrocarbons in the 

creosote- and CuNB-treated ties, and mixture sample (1:1 wt. %) from the pyrograms. (a) 

Fragments of m/z =76 for searching creosote compounds in the creosote-treated sample and 

mixture and (b) fragments of m/z = 71 for searching alkane hydrocarbons in the CuNB-treated 

sample and mixture. 
4. Research Team 

Dr. Nicole Labbé is an Associate Professor of Biomass Chemistry in the Center for Renewable 

Carbon at the University of Tennessee-Knoxville. She received her B.S. in Chemistry from 

University of Poitiers, France, M.S. and Ph.D. in Wood Sciences from University of Bordeaux, 

France. Her research interest focuses on understanding properties of biomass –its appearance, 

variability, and potential for conversion to various products such as fuels, chemicals and valueadded products. She is investigating new biological, thermal, and chemical routes to fractionate 

biomass and provide detailed understanding of plant cell walls, their roles in plant function, and 

factors controlling their recalcitrance and optimization of processes. In addition, she is 

developing high throughput techniques such near infrared, pyrolysis gas chromatography/mass 

spectrometry, and laser induced breakdown spectroscopy to rapidly assess biomass from 

laboratory to biorefinery scale. 

Dr. Pyoungchung Kim is a research scientist at the Center for Renewable Carbon at the 

University of Tennessee-Knoxville. He received his B.S. and M.S. in Environmental engineering 

from KonKuk University, South Korea, and Ph.D. in Environmental Engineering from the 

University of Tennessee, USA. His research interest lies on thermochemical conversion of 

biomass and various organic materials such as bioenergy crops, plastics, used railroad ties and 

agricultural wastes into biofuels, chemicals and value-added products. He is investigating 

optimization of pyrolysis processes for maximizing bio-products, upgrading and fractionation of 

bio-oils, and application of biochars as a soil amendment and environmentally friendly materials 

for pollution control. 

The Center for Renewable Carbon, in the University of Tennessee, Institute of Agriculture, is an 

internationally recognized leader in the development of new and/or improved bioenergy sources, 

biorefinery processes, bioproducts, and biomaterials that coordinates the science, knowledge transfer, and 

trains the workforce required to develop a sustainable and economically viable bioeconomy.