Role of Construction 

Debris in Release of 

Copper, Chromium, 

and Arsenic From 

Treated Wood 

Structures 

Stan T. Lebow 

Steven A. Halverson 

Jeffrey J. Morrell 

John Simonsen 

United States

Department of 

Agriculture 

Forest Service 

Forest 

Products 

Laboratory 

Research 

Paper 

FPL−RP−584

In cooperation 

with the 

United States 

Department of 

Transportation 

Federal 

Highway 

Administration
Abstract 

Recent research on the release of wood preservatives from 

treated wood used in sensitive environments has not considered 

the potential contribution from construction residues. This study

sought to develop leaching rate data for small construction 

debris and compare those to the release rate from treated wood 

itself. Western hemlock boards were pressure treated with 

chromated copper arsenate Type C (CCA-C), and then common 

construction tools were used to generate sawdust or shavings 

from those boards. These wood particles were then leached in 

deionized water, and the leaching rate was compared with that 

of solid wood samples cut from the same specimen. Release rate 

data from this study were also compared with those from endmatched samples that were leached in artificial rain in an earlier 

study. The release rates of copper, chromium, and arsenic from

CCA-C treated chain saw sawdust, circular saw sawdust, and 

spade bit shavings were many times higher than from solid 

wood when samples were immersed in water. There was little 

difference in the release rates among the three types of shavings 

and sawdust, despite differences in their particle sizes. The rates 

of release from decking exposed to rainfall were many times 

lower than that of construction debris or solid wood continually

immersed in water. These results show the importance of minimizing the amount of construction debris that is allowed to 

enter the aquatic environment. However, example calculations 

also demonstrate that if reasonable efforts are made to minimize 

release of construction debris, the contribution of these particles 

to the overall release of preservative from the structure will be 

minimal. 

Keywords: wood preservative, chromated copper arsenate, 

treated wood, construction debris, leaching 

June 2000 

Lebow, Stan T.; Halverson, Steven A.; Morrell, Jeffrey J.; Simonsen, John. 

2000. Role of construction debris in release of copper, chromium, and 

arsenic from treated wood structures. Res. Pap. FPL-RP-584. Madison, WI:

U.S. Department of Agriculture, Forest Service, Forest Products Laboratory. 

6 p. 

A limited number of free copies of this publication are available to the

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Acknowledgment 

The authors acknowledge the support of the U.S. Department 

of Transportation, Federal Highway Administration, for this 

project. 

Contents 

Page 

Introduction............................................................................1

Materials and Methods...........................................................1

CCA-C Treatment of Western Hemlock Boards................1

Preparing Sawdust, Shavings, and Blocks .........................2

Determining Particle-Size Distribution..............................2

Determining Release Rates................................................2

Results and Discussion...........................................................2

Particle-Size Distribution...................................................2

Release Rates From Construction Debris...........................4

Comparison With Release From Decking..........................4

Proportion of Total Leaching Caused by Construction 

Debris.................................................................................5

Conclusions............................................................................6

Literature Cited ......................................................................6
Role of Construction Debris in 

Release of Copper, Chromium, and 

Arsenic From Treated Wood Structures

Stan T. Lebow, Research Forest Products Technologist

Steven A. Halverson, Physical Science Technician

Forest Products Laboratory, Madison, Wisconsin

Jeffrey J. Morrell, Professor

John Simonsen, Associate Professor

Department of Forest Products, Oregon State University, Corvallis, Oregon 

Introduction 

Preservative-treated wood is widely used for construction of 

highway bridges and footbridges, wetland boardwalks, and 

other applications in or over water. Treated wood is used for 

these types of applications because it is economical, blends 

well with the environment, and is relatively easy to install. 

The wood is durable because the chemicals in the preservative are toxic to decay fungi and insects. However, these 

same chemicals are also potentially toxic to aquatic organisms. Concerns that chemicals might leach out of the wood 

and accumulate in the environment to harmful levels led to a 

recent evaluation of the leaching and biological impacts of 

four types of wood preservatives in a wetland boardwalk 

(Forest Products Laboratory 2000). Although all four wood 

preservatives released measurable amounts of chemicals into 

the environment, no detectable impact on aquatic insect 

populations at the sites was observed. However, because that 

study was designed to evaluate leaching from the treated 

structure, care was taken to minimize discharge of construction residues into the environment. In more routine construction projects, sawdust and shavings generated during construction might enter the water below the structure. It is 

important to understand the relative contribution that these 

construction residues might make to overall releases from the 

structure. 

Because of their greater surface area to volume ratio, small 

wood particles such as sawdust might contribute proportionally greater amounts to chemical release than the treated 

wood itself. In fact, the toxicity characteristic leaching procedure (TCLP) that is sometimes used to evaluate the potential toxicity of treated wood is designed to magnify leaching 

by requiring that solids be reduced to a size that will pass 

through a 9.5-mm (0.375-in.) screen (EPA 1996). Haloui and 

Vergnaud (1997) noted this effect on a larger scale, reporting 

that the rate of leaching of the wood preservative pentachlorophenol was much greater for samples with dimensions 

of 20 by 20 by 20 mm (0.8 by 0.8 by 0.8 in.) than for 

samples with dimensions of 40 by 20 by 20 mm (1.6 by 0.8 

by 0.8 in.). In general, previous leaching studies using small 

samples have reported higher leaching rates (Lebow 1996). 

However, the effects of smaller waste particles generated 

during construction are not known. This study sought to 

develop leaching rate data for smaller construction debris for 

comparison with release rates from wood treated with chromated copper arsenate type C (CCA-C). 

Materials and Methods 

The general approach used in this study was to treat boards 

with preservative and then use common construction tools to 

generate sawdust or shavings from those boards. These wood 

fragments were then leached in deionized water, and the 

leaching rate was compared, on a weight basis, to that of 

solid wood cut from the same specimen. 

CCA-C Treatment of Western 

Hemlock Boards 

Four No. 1 grade, western hemlock boards (Tsuga heterophylla (Raf.) Sarg.), 38 by 140 mm (1.5 by 5.5 in.) and 

2.44 m (8 ft) long were obtained from a mill in western 

Washington state. No attempt was made to select for sapwood or a specific grain orientation. A 406-mm- (16-in.-) 

long specimen and an end-matched 587-mm (23.1-in.) 

specimen were cut from each board and conditioned to constant weight at 23oC (74oF) and 65% relative humidity. Prior 

to treatment, both ends of each section were sealed with two 

coats of a neoprene rubber sealant to prevent end-grain penetration of preservative. The specimens were pressure treated 

with a 1.3% CCA-C solution (actives ratio of 17.4% CuO, 

46.9% CrO3, 35.7% As2O5) using an initial vacuum that 

reduced pressure to 17 kPa (5 inHg) for 30 min followed by 

a pressure period of 1,034 kPa (150 lb/in2

) for 2 h. Following 

treatment, the specimens were reweighed to determine the 

amount of solution uptake, and then each specimen was 

placed into a plastic bag and stored for 10 days at 23oC 
2 

(74oF) to allow for fixation of the CCA-C. The specimens 

were then stickered and air-dried in a room maintained at 

23oC (74oF) and 65% relative humidity. Only the 406-mm- 

(16-in.-) long specimens were used in this study. The 

587-mm- (23.1-in.-) long specimens were used in a previous 

study that assessed leaching in artificial rainfall (Lebow 

and Evans 1999). 

Preservative retention was determined by weight gain and by 

removing samples of the wood for chemical analysis. Samples for chemical analysis were removed by drilling a minimum of 20 holes, each 15 mm (0.6 in.) deep, in each specimen using a 6-mm- (0.25-in.-) diameter bit. The resulting 

shavings were collected and analyzed as specified in AWPA 

Standard Method A11–83 (AWPA 1998). The retention 

varied from 5.92 to 8.64 kg/m3

 (0.37 to 0.54 lb/ft3) as determined by weight gain and from 6.08 to 12.64 kg/m3

 (0.38 to 

0.79 lb/ft3

) as determined by chemical analysis. 

Preparing Sawdust, Shavings, 

and Blocks 

Wood particles were generated using three common construction tools: a circular saw, a chain saw, and a drill bit. In 

each case, an effort was made to collect a representative 

sample of the cross section of the specimen. First, one pass 

was made through each specimen with a chain saw that cut a 

6-mm- (0.25-in.-) wide kerf. The specimen and chain saw 

were placed inside a large plastic bag during cutting to capture all the sawdust generated. A new chain was used, and the 

chain was run without oil to prevent contamination of the 

sawdust. This technique produced between 12.4 and 15.7 g 

of sawdust from each specimen. Circular saw cutting was 

done inside a large plastic bag to collect all the sawdust. The 

circular saw was equipped with a new, 184-mm- (7.25-in.-) 

diameter, 24 tooth construction-and-framing carbide-tipped 

blade with a 2.5-mm (0.1-in.) kerf. The sawdust from three 

passes was combined, producing between 12.7 and 19.7 g of 

sawdust per specimen. Each specimen was then bored 

through the wide face in two locations using a 25-mm- 

(1-in.-) diameter wood boring spade bit. One hole was placed 

in the center of the board, and the other hole was placed at 

the edge of the board. Again, a plastic bag was used to collect all the shavings. This technique produced between 15.2 

and 18.6 g of sawdust per specimen. Finally, a 40-mm- 

(1.6-in.-) long by 38-mm- (1.5-in.-) thick by 140-mm- 

(5.5-in.-) wide block was cut from each specimen. The 

weight of these blocks ranged from 78.5 to 101.2 g. The 

blocks were then end-coated with neoprene rubber sealant to 

prevent leaching through the end-grain. 

Determining Particle-Size Distribution 

The samples were placed on a series of screens with successively smaller openings (Fig. 1) and mechanically agitated 

for 3 min. The particles retained on each screen were 

weighed, and the percentage of particles failing to pass 

through each mesh size was calculated (Fig. 1). 

Determining Release Rates 

The samples of sawdust or shavings generated from each 

specimen were sewed into polyester bags. Each bag was then 

placed into a 500-mL flask and submerged in 200 mL of 

deionized water. Blocks cut from the specimens were placed 

into glass jars and submerged in 300 mL of deionized water. 

The filled flasks and jars were subjected to a vacuum that 

reduced pressure to 17 kPa (5 inHg) for 15 min and then 

placed on a mechanical agitator. The leaching samples were 

continuously agitated for 50 days, with frequent collection of 

the leachate for analysis (Table 1). At each collection, the 

available water was drained off the specimens and again 

replaced with 200 mL (sawdust and shavings) or 300 mL 

(blocks) of deionized water. Concentrations of copper, chromium, and arsenic in the leachate were determined by atomic 

absorption analysis, using either furnace or flame atomization, as appropriate. The results were expressed as weight of 

chemical lost per gram of wood. 

Results and Discussion

Particle-Size Distribution 

As might be expected, the shavings generated by the spade 

bit contained a higher proportion of large particles than did 

the sawdust generated by the chain saw or circular saw 

(Fig. 1). More than 50% of the spade bit shavings failed to 

pass through the screen with the 2,000-μm (0.08-in.) openings. The chain saw produced intermediate-sized particles, 

with the majority passing through the 2,000-μm (0.08-in.) 

openings but failing to pass through the 840-μm (0.03-in.) 

openings. Particle sizes generated by the circular saw were 

both smaller and more widely distributed than those generated by the other two tools. This suggests that the rate of 

release from the circular saw particles would be higher than 

from particles generated by the chain saw or spade bit. 

0 

10 

20 

30 

40 

50 

60 

Percentage retained on mesh 

2000 840 600 425 300 250 212 180 0

Screen mesh opening (μm)

Circular saw

Spade bit

Chain saw

0 

10 

20 

30 

40 

50 

60 

Percentage retained on mesh 

2000 840 600 425 300 250 212 180 0

Screen mesh opening (μm)

Circular saw

Spade bit

Chain saw

Figure 1—Distribution of particle sizes generated 

by the three types of construction tools. 
3 

Table 1—Average copper, chromium, and arsenic release rates from construction particles and solid wooda

Release rate (μg/day/gram of sampleb

) 

Copper Chromium Arsenic 

Type of sample 

Total 

days 

leached 

Days in 

leaching 

interval Mean SD Mean SD Mean SD 

Block 0.08 0.08 10.55 4.19 12.53 4.42 24.64 12.15 

Chain saw 0.08 0.08 417.51 91.16 303.42 39.27 208.99 1.72 

Spade bit 0.08 0.08 288.65 77.66 352.26 47.95 179.80 0.42 

Circular saw 0.08 0.08 345.39 76.55 381.99 39.16 208.39 21.13 

Block 0.25 0.17 4.00 1.65 4.79 1.71 13.74 6.49 

Chain saw 0.25 0.17 140.17 35.92 99.46 9.48 105.37 1.48 

Spade bit 0.25 0.17 96.91 32.50 111.58 9.37 89.24 0.69 

Circular saw 0.25 0.17 116.18 23.07 118.61 6.58 97.61 1.38 

Block 1 0.75 2.36 1.48 1.48 0.54 4.42 1.49 

Chain saw 1 0.75 39.54 9.59 19.14 1.14 22.69 0.23 

Spade bit 1 0.75 23.02 7.87 19.38 2.13 19.40 0.34 

Circular saw 1 0.75 28.23 6.28 20.30 2.53 21.40 0.17 

Block 2 1 2.46 0.57 0.72 0.14 3.51 0.24 

Chain saw 2 1 20.55 4.52 7.49 0.23 13.12 0.30 

Spade bit 2 1 11.69 4.16 7.07 0.57 10.94 0.21 

Circular saw 2 1 14.02 3.50 7.47 0.49 12.23 0.10 

Block 4 2 1.35 0.58 0.39 0.09 2.04 0.18 

Chain saw 4 2 10.39 2.08 3.28 0.19 6.41 0.06 

Spade bit 4 2 5.82 2.05 2.87 0.34 5.52 0.17 

Circular saw 4 2 6.88 1.60 2.95 0.28 5.78 0.58 

Block 7 3 0.90 0.27 0.30 0.12 0.46 0.35 

Chain saw 7 3 6.81 2.00 2.51 0.17 3.83 0.08 

Spade bit 7 3 4.20 1.29 2.39 0.23 3.69 0.41 

Circular saw 7 3 4.40 0.86 2.85 0.21 4.28 0.25 

Block 9 2 0.82 0.28 0.34 0.17 0.33 0.17 

Chain saw 9 2 8.80 2.50 3.13 0.27 6.60 0.23 

Spade bit 9 2 4.90 1.49 3.07 0.14 5.90 0.23 

Circular saw 9 2 5.37 0.99 3.55 0.39 6.57 0.74 

Block 11 2 0.63 0.20 0.25 0.08 0.28 0.11 

Chain saw 11 2 6.80 1.73 3.06 0.29 7.03 0.14 

Spade bit 11 2 3.97 1.34 2.83 0.23 5.75 0.55 

Circular saw 11 2 4.47 0.75 3.24 0.47 5.32 1.15 

Block 14 3 0.59 0.11 0.21 0.10 0.32 0.15 

Chain saw 14 3 4.38 0.89 2.02 0.29 4.71 0.22 

Spade bit 14 3 2.56 0.90 1.83 0.23 3.99 0.46 

Circular saw 14 3 2.91 0.55 2.32 0.24 4.13 0.78 

Block 17 3 0.54 0.15 0.22 0.06 0.26 0.08 

Chain saw 17 3 3.67 0.78 1.88 0.27 4.29 0.25 

Spade bit 17 3 2.11 0.85 1.49 0.24 3.63 0.59 

Circular saw 17 3 2.38 0.46 2.22 0.30 3.73 0.64 

Block 22 5 0.36 0.08 0.04 0.05 0.09 0.00 

Chain saw 22 5 2.43 0.36 0.53 0.07 1.88 0.10 

Spade bit 22 5 1.27 0.43 0.16 0.07 1.38 0.07 

Circular saw 22 5 1.76 0.43 0.41 0.24 1.50 0.07 

Block 28 6 0.34 0.14 0.07 0.04 0.07 0.00 

Chain saw 28 6 2.11 0.35 0.53 0.06 1.49 0.10 

Spade bit 28 6 1.16 0.43 0.20 0.09 1.22 0.05 

Circular saw 28 6 1.57 0.33 0.42 0.17 1.28 0.10 

Block 36 8 0.19 0.09 0.07 0.03 0.16 0.02 

Chain saw 36 8 1.46 0.38 0.40 0.05 0.71 0.02 

Spade bit 36 8 0.89 0.35 0.21 0.04 0.54 0.07 

Circular saw 36 8 1.22 0.28 0.36 0.13 0.59 0.06 

Block 50 14 0.27 0.09 0.03 0.04 0.10 0.02 

Chain saw 50 14 1.09 0.17 0.26 0.06 0.37 0.03 

Spade bit 50 14 0.58 0.29 0.09 0.04 0.27 0.04 

Circular saw 50 14 0.77 0.24 0.22 0.10 0.31 0.05 

a

Mean and standard deviation (SD) are for four replicates. 

b

Rate is calculated using the number of days since the previous water replacement (days in leaching interval). 
4 

Figure 2—Rate of release of (a) copper, (b) chromium, 

and (c) arsenic from solid wood and the three types of 

construction debris during 50 days of water immersion. 

As discussed below, this premise was only partially supported by the release rate data. The particle sizes evaluated in 

this study are meant only to serve as examples. It is readily 

apparent that different types of tools, different drill bits, and 

different saw blades could all greatly affect the particle size 

and size distribution of construction debris. 

Release Rates From 

Construction Debris 

The amounts of copper, chromium, and arsenic released from 

the solid wood sample were many times lower than those 

from sawdust or drill shavings (Fig. 2). The effect was greatest for copper, where the average release was initially more 

than 20 times greater from the particles than from the solid 

wood (Table 1). This gap between the solid wood and particulate leaching rates narrowed with time, although the 

release rate from the particles remained several times higher 

after 50 days. Eventually, one might expect that the reservoir 

of available CCA-C within the particles would become so 

depleted that their release rate would drop below that of 

solid wood. 

Little difference in release rates was noted among the three 

types of sawdust or shavings. This is somewhat surprising 

given the differences in particle-size distribution between the 

three groups (Fig. 1). As might be expected based on their 

larger particle size, release from the spade-bit shavings did 

tend to be slightly lower than from either type of sawdust. 

This trend was especially evident for the later stages of 

chromium release. However, releases from the chain saw 

sawdust were at least as high as those from the circular saw 

sawdust, despite the differences in particle-size distribution. 

In addition to size differences, it is likely that these tools 

produce particles with different surface topographies that 

might affect leaching. In general, release rates from sawdust 

and shavings generated during construction were much 

greater than from solid wood. 

Comparison With Release 

From Decking 

The vast majority of treated wood used in construction is not 

immersed in water; it is used above the ground or above the 

water. Treated wood used over standing water would be 

subjected to leaching only intermittently, during periods of 

precipitation, whereas construction residues would fall into 

the water. Thus, it may be more meaningful to compare the 

rate of release from treated wood subjected to rainfall to that 

of construction residue immersed in water. 

In a previous study, end-matched 587-mm- (23.1-in.-) long 

specimens cut from the same boards used in this study were 

subjected to leaching by artificial rainfall (Lebow and Evans 

1999). Because they are end-matched specimens and treated 

in the same charge as the specimens used in this study, they 

have very similar CCA-C retention and penetration. The 

release rates from the construction debris and from the rainwater specimens can be most directly compared after 

28 days, when leachate samples were collected from both 

types of samples. At the 28-day sampling point, the decking 

specimens had been subjected to an average of 198 mm 

(7.8 in.) of artificial rainfall, which corresponds to a yearly 

rainfall amount of approximately 2.54 m (100 in.). The high 

amount of rainfall represents a fairly severe aboveground 

leaching exposure. However, as can be seen from Figure 3, 

the total amount of CCA-C released from the decking specimens was much lower than from any of the types of samples 

in the construction debris study, including the solid wood 

samples. It is apparent that constant immersion of treated 

0.1

1 

10 

100 

1,000 

0 10 20 30 40 50 

Solid wood

Chain saw

Spade bit

Circular saw

Chromium release(μg/day/g of wood)

0.01

(b)

0.1

1 

10 

100 

1,000 

0 10 20 30 40 50 

Solid wood

Chain saw

Spade bit

Circular saw

Chromium release(μg/day/g of wood)

0.01

(b)

0.01 

0.1 

1 

10 

100 

1,000 

Arsenic release

(ug/day/g of wood)

0 10 20 30 40 50 

Total days of leaching

Solid wood

Chain saw

Spade bit

Circular saw

(c)

0.01 

0.1 

1 

10 

100 

1,000 

Arsenic release

(ug/day/g of wood)

0 10 20 30 40 50 

Total days of leaching

Solid wood

Chain saw

Spade bit

Circular saw

(c)

1 

10 

100 

1,000 

Copper release

(μg/day/g of wood)

0 10 20 30 40 50 

Solid wood

Chain saw

Spade bit

Circular saw

(a)

1 

10 

100 

1,000 

Copper release

(μg/day/g of wood)

0 10 20 30 40 50 

Solid wood

Chain saw

Spade bit

Circular saw

(a)
5 

Figure 3—Total release of copper, chromium, and 

arsenic from solid wood and construction debris 

immersed in water and from decking exposed to 

artificial rainfall. 

wood or treated wood particles causes a higher rate of leaching than does exposure to rainfall. Discharge of construction 

debris into standing water increases leaching in two ways. 

First, the smaller size of the particles increases the leaching 

rate and second, immersion in water causes more rapid leaching than does exposure to precipitation only. 

Proportion of Total Leaching 

Caused by Construction Debris 

Particulate construction debris clearly releases CCA-C components much more rapidly than does the solid treated wood 

within the structure itself. However, in most cases, the volume of treated wood used in a structure will be many times 

greater than that of the debris generated during construction. 

To put the relative amounts of CCA-C released from the 

treated structure and construction debris in perspective, it is 

useful to estimate releases from a hypothetical construction 

project. 

Consider CCA-C treated decking on a wetland boardwalk 

30.5 m (100 ft) long and 1.2 m (4 ft) wide. The construction 

crew might purchase standard 38- by 140-mm (nominal 2- by 

6-in.) boards in 2.4-m (8-ft) lengths and cut them in half to 

create the 1.2-m- (4-ft-) long deck boards. The boardwalk 

would require approximately 214 deck boards, or 107 of the 

2.4-m- (8-ft-) long boards, necessitating 107 saw cuts to 

create the decking. If we assume that the 107 saw cuts are 

made with a circular saw blade similar to that used in this 

study and that 100% of the sawdust was discharged into the 

standing water, we can estimate the amount of CCA-C components released by the sawdust relative to that released by 

the decking, which is exposed to leaching by rainfall only. To 

make the comparison, we must assume that the CCA-C retention in the boards is similar to that of this study and base the 

releases from the sawdust and deck boards on the 28-day 

release data discussed earlier (Fig. 3). Given those assumptions, approximately 562 g of sawdust would be generated, 

and after 28 days, that sawdust would have released 91 mg of 

copper, 67 mg of chromium, and 90 mg of arsenic into the 

water. Similarly, if we assume that each of the 214 1.2-m- 

(4-ft-) long deck boards weighs 2.912 kg, we can calculate 

that approximately 2.493 g of copper, 533 mg of chromium, 

and 1.870 g of arsenic would be released by rainfall runoff 

from the decking. In other words, the sawdust would have 

contributed approximately 4% of the copper, 11% of the 

chromium, and 5% of the arsenic released by the construction project during the first 28 days. Thus, although the rate 

of release from construction debris is much greater than from 

the wood used in the structure, the greater volume of wood 

used in the structure will cause the structure itself to contribute the bulk of the preservative released. And, as noted earlier, a previous boardwalk study reported that although four 

types of treated wood release measurable amounts of chemicals into the environment, no detectable impact on aquatic 

insect populations was observed (Forest Products Laboratory 

2000). 

Many factors could affect the proportion of release contributed by the construction debris. For example, lesser amounts 

of rainfall would reduce the proportion released from the 

decking, while longer periods of time would tend to further 

diminish the contribution of construction debris. Because 

small particles release preservative at a higher rate and have 

a smaller reservoir of unleached preservative than does solid 

wood, construction debris would be expected to make a 

much greater contribution to overall leaching in the first few 

months after construction, and much less of a contribution in 

the following years. 

This comparison also assumes that both the construction 

debris and the decking release preservative uniformly into 

the surrounding environment. In practice, construction debris 

would be more likely to create localized pockets of contamination in the area immediately surrounding the site of their 

deposition. Release is also not uniform below decking, as 

runoff from precipitation tends to be channeled into specific 

flow paths. Lebow and others (2000) noted the high spatial 

variability of contamination in soil below boardwalk decking. 

Despite the less substantial contributions of construction 

debris to the overall leaching rates, these releases are clearly 

preventable. Potential release from debris could be most 

effectively reduced through conscientious construction practices. One desirable practice is to specify that as much material as possible be cut to size, or fabricated, prior to treatment. This practice not only minimizes the generation of 

construction debris but also lessens the exposure of untreated 

wood in the center of the treated members. Where field 

fabrication is necessary, it should be conducted over tarps or 

plastic and away from sensitive environments. In most construction projects, however, some field fabrication occurs 

within the structure itself, and over standing water. If possible, this material should also be contained and collected. 

0

50

100

150

200 

250 

Total release, 28 days

(μg/g of wood)

Copper Chromium Arsenic

CCA-C element

21

8

21

230

108

162

138

106

149

164

120

162

4 1 3

Chain saw dust Spade bit

shavings Circular saw dust Decking (rainfall)

Solid wood

0

50

100

150

200 

250 

Total release, 28 days

(μg/g of wood)

Copper Chromium Arsenic

CCA-C element

21

8

21

230

108

162

138

106

149

164

120

162

4 1 3

Chain saw dust Spade bit

shavings Circular saw dust Decking (rainfall)

Solid wood
6 

Conclusions 

The release rate of copper, chromium, and arsenic from 

CCA-C treated chain saw sawdust, circular saw sawdust, and 

spade bit shavings was found to be many times higher, per 

unit weight of wood, than from solid wood when samples 

were immersed in water. However, there was relatively little 

difference in the release rates among the three types of shavings and sawdust, despite differences in their particle sizes. 

Through comparison with a previous study, it was calculated 

that the rate of release from decking exposed to leaching only 

by rainfall is many times lower than that of construction 

debris or solid wood continually immersed in water. However, the release from debris was estimated to be only a small 

fraction of the total release in a hypothetical construction 

project. Chemical releases from construction debris could be 

minimized if reasonable efforts were made to fabricate the 

lumber prior to treatment and to collect and contain debris 

generated during construction. 

Literature Cited 

AWPA. 1998. Book of standards. A11–93. Standard method 

for analysis of treated wood and treating solutions by atomic 

absorption spectroscopy. Granbury, TX: American Wood 

Preservers’ Association. 

EPA. 1996. Method 1311, Toxicity characteristic leaching 

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