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Use of anti-stain chemical treatments by the western U.S. softwood lumber industry, 1999. (Solid Wood Products).

We assessed the use of anti-stain chemical treatments within the softwood lumber industry in the western United States through a questionnaire mailed to producing members of the Western Wood Products Association in spring 2000. Responding mills (56% response rate) produced 5.6 billion board feet (BBF) of lumber in 1999, approximately 33 percent of the total production in the western region. Only 9 of the 69 responding mills reported use of anti-stain chemical treatments. The volume of lumber treated by these mills was roughly one-half of their total production, or 478 million board feet (MMBF). According to a 1994 study in the western region, responding mills produced 6.4 BBF, 21 of 106 responding mills used anti-stain treatments, and the anti-stain-treated volume was 913 MMBF. Thus, the use of anti-stain chemical treatments appears to be declining in the western United States.


Stain and mold prevention in freshly sawn lumber is an important component in many quality control programs, particularly in mills that export a considerable volume of green lumber. For decades, stain and mold prevention primarily involved application of fungicides shortly after sawing. Changing public perceptions and increasing regulatory scrutiny have encouraged many mills to seek nonchemical alternatives for stain and mold control. Primary among these alternatives is additional kiln capacity, which enables mills to dry all lumber below 20 percent moisture content, and thereby eliminates the risk of stain. Hansen and Morrel (1) surveyed mills in 12 states in the western United States regarding their practices in preventing stain and their attitudes about the chemicals they used. Results of their 1994 survey suggested that many mills had ceased or sharply curtailed use of anti-stain compounds, although discoloration remained a major quality concern. The survey also suggested that overall chemical usage was declining in the region. To develop more current information on trends in stain and mold control, we resurveyed mills in the region in 1999 and this report summarizes the results of that survey.


The sample population comprised producing members of the Western Wood Products Association (WWPA), i.e., lumber-producing companies in 11 western states. After adjusting for incorrect addresses, WWPA members who do not produce lumber, and companies with multiple locations, we sampled a total of 123 mills. The questionnaire sent to the mills was nearly identical to the questionnaire used in 1994, except for the inclusion of questions about a new brand of anti-stain chemical and whether surface mold or blue-stain deeper in the wood is more important to control. The survey focused on production statistics, anti-stain treatment methods and chemicals, and attitudes regarding anti-stain treatments.

The questionnaire was mailed with a cover letter and postage-paid, self-addressed reply envelope to quality control supervisors at each of the selected mill sites. A reminder postcard was mailed after approximately 2 weeks. A second copy of the questionnaire and cover letter, and postage-paid, self-addressed reply envelope were mailed about 2 weeks after the reminder postcard to all nonresponding mills. Finally, a second reminder postcard was mailed about 6 weeks after the original mailing. We received 69 usable responses, a 56 percent response rate. Data were coded and checked for errors, particularly where production statistics deviated from reported values. (2)


Total 1999 lumber production reported by the 69 respondents was 5.6 billion board feet. This volume represents approximately 33 percent of the total volume produced in the western region of the United States in that year. (3) Nine respondents used anti-stain chemical treatments on at least a portion of their lumber production. Total production of lumber at mills using anti-stain chemicals was about 900 million board feet (MMBF), of which about 478 MMBF was treated with anti-stain chemicals. Nearly 4 MMBF, i.e., less than 1 percent of the treated lumber, were exported from the United States. Six of the nine treating mills treated both rough and surfaced lumber. Of the remaining three mills, two mills treated surfaced lumber exclusively, and one mill treated only rough lumber. Six mills applied chemicals by dipping, two used low-pressure spray units, and one used a high-pressure linear spray unit. Three of the nine companies indicated that they used more than one application method.

Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) was the most treated species, and approximately 463 MMBF were treated in 1999 (Table 1). Western hemlock (Tsuga heterophylla) and ponderosa pine (Pinus ponderosa Dougl. ex Laws.) were also treated but in relatively small quantities.

The nine mills that treated lumber used three chemical products:

1. NP-1[R] (Kopcoat, Inc., Pittsburgh, Pennsylvania) a mixture of didecyldimethyl ammonium chloride and 3-iodo 2 propynyl butylcarbamate;

2. Britewood S[R] (Contechem, Inc., Portland, Oregon) orthylphenlyphenbate;

3. Britewood XL[R] (Contechem, Inc., Portland, Oregon) propiconazole.

Five of the nine treating mills based their selection of chemical on personal experience. Two mills indicated that their chemical supplier was the basis for their chemical selection. One mill based their selection on other mill's experience and one mill did not specify their basis of chemical selection. Treating mills used chemical dilution rates ranging from 1:9 to 1:100 (Table 2). Specific chemical brands had been used for 12 to 96 months, a period of time long enough to suggest that most of the treating mills were satisfied with the chemical they used (Table 2).

Using a 5-point scale (1 = agree; 3 = neutral; 5 = disagree), respondents were asked to give their level of agreement with the following four statements regarding their selection of anti-stain chemicals.

1. The chemical we currently use has a low price.

2. The chemical we currently use poses few handling problems.

3. The chemical we currently use performs well in preventing stain.

4. The chemical we currently use is a good value.

Statement 3 obtained a mean value of 1.33 (Table 3), which indicates that most mills viewed performance as the primary criterion for selecting and retaining a chemical brand.

Of the 69 respondents in this study, 12 mills reported losses due to staining, including losses resulting from materials falling into a lower grade. The sum of reported losses was $1.3 million, or an average of $108,333 per mill. Losses varied widely, however. One non-treating mill reported losing $500,000. Among the non-treating mills, 28 reported no losses, and 20 mills did not answer the question. Among the mills using anti-stain treatments, four reported no losses and five did not answer the question. Scheffer conservatively estimated total U.S. annual stain losses to be $10 million in 1973. (4) Hansen and Morrell (1) reported that mills in their study of the western U.S. softwood lumber industry lost an average of $61,000. The accuracy of these three estimates is in doubt. Quantifying stain loss is difficult for several reasons. First, stained lumber is still saleable, though often at a lower price. Several mills reported they did not track that type of information. Second, the wide variation in reporte d losses creates doubt about the accuracy of the estimates. Finally, respondents may be hesitant to report that their practices resulted in significant economic losses.

Responding mills were asked to indicate how acceptable stain was in specific markets based on the following categories: acceptable, neutral, and not acceptable (Table 4). Respondents perceived stain to be least accepted in export markets and most accepted by professional contractors. Given the low percentage of wood that was exported from the responding mills and the perceived willingness of other markets to absorb these materials, it is interesting to note that many mills continue to treat wood for domestic use. This suggests that domestic consumers may be less accepting of this material than many mills believe.

Mills responded to the question "Is it more important to control surface mold or blue stain deeper in the wood;" results (47% and 53%, respectively) indicated that neither discoloration condition was perceived clearly as the more important to control.

Mills that had used anti-stain treatments in the past and had since stopped reported that they discontinued use for the following reasons:

* Kiln-dried all production before stain developed (6 mills);

* Concerned about toxicity to employees and environment (4 mills);

* No longer shipped product offshore (3 mills);

* Cost of chemical treatment (1 mill);

* Available chemicals were not effective in preventing stain (1 mill).

Responding mills showed no clear tendency as to whether or not they would use a non-chemical anti-stain treatment if it were available: 53 percent would use a non-chemical treatment and 47 percent would not. Of the 28 responding mills indicating they would not use an alternative non-chemical anti-stain treatment, 14 mills indicated that stain was not a defect for their product, 4 mills indicated that they had enough dry kiln capacity to prevent staining of lumber, 4 mills indicated they did not want to incur increased material-handling costs, 2 mills indicated that there could still be concerns about environmental issues despite the non-chemical treatment, and 2 mills indicated that the logs they receive already have blue stain in them, thus negating the need for treatment, and 2 mills offered no explanation.

The format of the 1994 questionnaire was nearly identical to that used in 1999, and the population of interest in both studies comprised producing members of the WWPA. The 1999 study was sent to 123 mills (56% response) while the 1994 study was sent to 174 mills (61% response). In comparing the studies, the most remarkable contrast was that the volume of lumber anti-stain treated by respondents in the 1999 study (478 MMBF) was roughly half that of the respondents in the 1994 study (913 MMBF). Roughly equal volumes of the lumber production of the western U.S. region (33% in 1999 and 37% in 1994) were represented. Another obvious difference was that 25 percent of the treated lumber was destined for export in the 1994 study, whereas less than 1 percent of the treated lumber was exported in 1999. Finally, the proportion of mills that treat lumber with anti-stain chemicals decreased from nearly 20 percent in 1994 to 13 percent in 1999. Reasons cited for the declining use of anti-stain treatments were consistent i n both studies. This suggests that most mills disliked dealing with chemicals to the extent that they were willing to either accept discoloration losses or the higher costs associated with kiln-drying.


Survey results suggest that the use of anti-stain chemical treatments continues to decline in the western U.S. softwood lumber industry. The most likely causes are:

* A reduction in the amount of softwood lumber being exported;

* Increased dry-kiln capacity;

* Continued concern about the toxicity of chemicals to the environment and workers.

Volume of lumber produced by mills that apply anti-stain treatments. (a)

 Total volume Volume
Species produced anti-stain treated


Douglas-fir 618 463
Western hemlock (hem-fir) 47 5
Other 12 10

Total 677 478

 Percent of volume
Species anti-stain treated


Douglas-fir 75
Western hemlock (hem-fir) 11
Other 83

Total 71

(a)Figures based on eight of nine respondents who used anti-stain
treatments on lumber during 1999. One Brightwood XL user provided no
species breakdowns.

Chemicals used and volume of each species treated, by type of anti-stain
chemical. (a)

 NP-1[R] Britewood S[R]

Number of mills using chemical 5 1

Application technique (no. of mills)
 Dip tank 3 1
 Low-pressure spray unit 1 --
 High-pressure spray unit 1 --
Ratio of chemical to water 1:30 to 1:70 1:50
Period of use (months) 30 to 96 36

Wood species treated (MMBF) (a)
 Douglas-fir 315 --
 Western hemlock -- --
 Ponderosa pine -- 1

 Britewood XL[R]

Number of mills using chemical 3

Application technique (no. of mills)
 Dip tank 3
 Low-pressure spray unit --
 High-pressure spray unit --
Ratio of chemical to water 1:9 to 1:100
Period of use (months) 12 to 36

Wood species treated (MMBF) (a)
 Douglas-fir 141
 Western hemlock --
 Ponderosa pine 6

(a)Figures based on eight of nine respondents who used anti-stain
treatments on lumber during 1999. One Brightwood XL user provided no
species breakdowns.

Attitude of respondents concerning cost, handling, and efficacy of
anti-stain chemicals used in their mills. (a)

Statement Mean scale value SD (b)

The chemical we currently use has a low 3.44 .88
The chemical we currently use poses few 1.78 1.09
 handling problems
The chemical we currently use performs 1.33 .50
 well in preventing stain
The chemical we currently use is a good 2.11 .93

(a)Values based on a scale of 1 (agree) to 5 (disagree). Figures based
on nine of nine of nine respondents who used anti-stain treatments on
lumber during 1999.

(b)SD = standard deviation.

Producer perceptions concerning the willingness of various customer
groups to accept stained lumber.

Market Responses (a) 1 (acceptable) 2 (neutral)


Export 42 0 12
Moulding/millwork 50 8 14
Windows/doors 51 8 19
Homecenters/lumberyards 51 16 39
Glulam/other industrial 45 20 45
Professional contractors 47 45 42

Market 3 (not acceptable)


Export 88
Moulding/millwork 78
Windows/doors 73
Homecenters/lumberyards 45
Glulam/other industrial 35
Professional contractors 13

(a) Denotes the number of responses for that question out of a total of

(1.) Hansen, E.N. and J.J. Morrell, 1997. Use of anti-stain chemical treatments by the western U.S. softwood lumber industry, 1994. Forest Prod. J. 47(6):69-71.

(2.) Miller Freeman Publications. 1998. 1999 Directory of the Wood Products Industry. Miller Freeman Pub., San Francisco, CA.

(3.) R.E. Taylor and Associates. 1999. 2000 Edition Wood Markets, The Solid Wood Products Outlook 2000 to 2004. International Wood Markets Research Inc., Vancouver, BC, Canada. pp. 129-137.

(4.) Scheffer, T.C. 1973. Microbiological deterioration. In: Wood Deterioration and its Prevention by Preservative Treatments. Vol. 1. D.D. Nicholas, ed. Syracuse Univ. Press, Syracuse, N.Y. pp. 31-106.


(*.) Forest Products Society Member.

The authors are, respectively, Graduate Student, Associate Professor/Extension Specialist, and Professor, Dept. of Forest Products, College of Forestry, Oregon State Univ., Corvallis, OR 97331-7402. This is paper 3445 of the Forest Res. Lab., OSU. This paper was received for publication in February 2001. Reprint No. 9265.

[c] Forest Products Society 2002
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Author:Anderson, Roy C.; Hansen, Eric; Morrell, Jeff
Publication:Forest Products Journal
Article Type:Statistical Data Included
Geographic Code:1USA
Date:Apr 1, 2002
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