TECHNICAL MEMORANDUM
TO:
Kelly Moran, Palo Alto Regional Water Quality Control Plant
FROM:
Bill Johnson, EIP Associates
DATE:
April 23, 1999
SUBJECT:
Alternatives to Pentachlorophenol-Treated Utility Poles
Wood preservatives are used to protect wood against rot and infestation. Pentachlorophenol
(also known as “penta” or “PCP”) is a common wood preservative that contains traces of
polychlorodibenzo-p-dioxins (referred to collectively as “dioxin”). In the U.S., about 8% of
treated wood products are preserved with PCP (U.S. Environmental Protection Agency
1993). The types of products most commonly treated with PCP are lumber and timber to be
used as fence posts, pilings, poles and cross arms, and railroad cross ties and switches. Over
time, a portion of the PCP (and presumably its dioxin contaminants) slowly leaches or
evaporates from the PCP-treated wood and enters the environment. The City of Palo Alto
purchases and installs PCP-treated utility poles and cross arms. This memorandum reviews
alternative wood preservatives and alternative pole materials, and considers the
environmental and operational issues for each of them.
Current City Use of PCP
The City of Palo Alto maintains about 6,000 utility poles. About 5,900 of these poles are
co-owned (40%) by Pacific Bell, which rents space to Cable Co-op. About 60% to 70% of
the 6,000 poles are in back yards, rather than along street fronts. Access to these locations
can be limited (Thomas and Marshall 1998). Palo Alto buys about 100 to 200 utility poles
each year. The Palo Alto Utilities Department specifies PCP-treated poles for its purchases
(Lynn 1998).
Wood Preservatives
Most non-PCP treated wood products are preserved with creosote or, more commonly,
arsenical preservatives. The use of creosote has declined in recent years because it contains
roughly 85% polynuclear aromatic hydrocarbons, which pose human and environmental
hazards (U.S. Environmental Protection Agency 1993). Both creosote and PCP are dissolved
in organic solvents when applied to wood. Waterborne preservatives, which use water to
dissolve the wood preservative when it is applied to the wood, pose fewer industrial hazards
and result in less waste because wastewater is typically reused. Therefore, the use of
waterborne preservatives has grown. Waterborne preservatives account for about 70% of
treated wood products (U.S. Environmental Protection Agency 1993).
(,3$662&,$7(60217*20(5<675((768,7(6$1)5$1&,6&2&$/,)251,$
7HOHSKRQH)DFVLPLOH(PDLOVI#HLSDVVRFLDWHVFRP
The most common waterborne preservatives are arsenicals, such as chromated copper
arsenate (“CCA”). Arsenicals contain arsenic, and most also contain chromium, copper, or
zinc to various degrees. The use of CCA results in fewer air emissions and less leaching than
PCP or creosote; however, the presence of arsenic, chromium, and copper poses different
human and environmental concerns. Ammoniacal copper/quaternary ammonium (also
known as “ammoniacal copper quat” or “ACQ”) is a somewhat more expensive alternative
that is less toxic than CCA because it does not contain arsenic. It does contain copper, which
poses environmental concerns related to storm water runoff.
Whereas creosote, CCA, and ACQ could be used as alternatives to dioxin-tainted PCP, these
possible alternatives contain other chemicals that make the overall environmental benefit of
such a substitution unclear. Table 1 lists known wood preservatives that are commercially
available or under investigation. As shown in Table 1, alternatives to PCP, creosote, CCA,
and ACQ exist; however, most are not commonly available in commercial treated wood
products. Many are sold for on-site application, such as treating holes or cuts in otherwise
treated wood. Unlike PCP, the alternatives are assumed to contain negligible dioxin
concentrations, but evidence to rule out the presence of dioxin in each case is not readily
available.
Some of the more promising alternatives are borates, such as disodium octaborate
tetrahydrate. Borates are generally non-toxic and considered by some to be the safest
alternative wood treatment available. They have some drawbacks, however. They protect
wood against fungi and wood-eating insects, but not mold and mildew. They are water
soluble; therefore, their utility outdoors is limited. They are generally unsuitable to preserve
wood that will be in contact with soil or exposed to weather (e.g., utility poles or fence
posts). Commercial products containing borates are just now becoming available. Rods of
fused borate and injectable gel products take advantage of the solubility of borates. When
placed inside a pole set in soil, water moving from the soil into and through the pole
distributes the borates, thereby providing protection for 3 to 10 years (Quarles 1998). When
all the borates have leached through the wood, they must be replaced or the wood will decay.
Therefore, the use of borates where soil or water contact is possible requires more
maintenance than the use of traditional preservatives, and may result in a substantially shorter
service life.
Attachment A contains notes from various sources regarding alternative wood preservatives.
Non-Wood Utility Poles
Because the available alternative chemical treatments to preserve wood may pose human
health and environmental hazards, are unproven in the marketplace, or would require
substantial maintenance, some have recommended replacing wood products with non-wood
alternatives. Some alternatives to treated utility poles include recycled steel, reinforced
concrete, and fiberglass reinforced composite. Another alternative to using treated wood
utility poles is to install utility lines underground, as is already occurring in Palo Alto on a
phased basis. These alternatives are discussed further in Attachment B, which contains an
excerpt from Poison Poles – A Report About Their Toxic Trail and Safer Alternatives
(National Coalition Against the Misuse of Pesticides 1997).
2
As indicated in the attached excerpt, steel is the most common alternative utility pole
material. Whereas the average cost of a treated wood pole is reported to range from about
$213 to about $360, a steel pole costs about $265 to $315 plus freight. A steel pole can be
expected to remain in service for about 80 years, compared to about 40 years for a typical
treated wood pole. Furthermore, steel is recyclable, which provides economic value when
decommissioned. The use of alternative pole materials could help reduce the use of chemical
wood preservatives, including PCP and its traces of dioxin.
Evaluation by Palo Alto Utilities Department
PCP-treated utility poles are the industry standard. The Palo Alto Utilities Department has
tried utility poles treated with other types of wood preservatives. The primary concern about
the alternative preservatives is that they result in a shorter pole life than when PCP is used.
Poles treated with other preservatives do not last as long or perform as well. Without
maintenance, PCP-treated utility poles last about 30 years. With Palo Alto’s maintenance
program, PCP-treated utility poles last longer than 30 years. The Palo Alto Utilities
Department has also tried other types of pole materials, including steel, fiberglass, and
concrete. These alternative poles were difficult to move into position and difficult to climb.
This poses potential problems, particularly where utility poles are located in back yards,
away from streets, where access is limited (Thomas and Marshall 1998).
The Palo Alto Utilities Department believes PCP-treated wood is the most appropriate
material currently available for utility poles. The Utilities Department intends to continue
monitoring new wood preservatives and pole materials, and will consider trying promising
materials if available (Thomas and Marshall 1998). In the meantime, the Utilities
Department is gradually removing poles from service and replacing them with underground
utilities. Although this process is relatively slow, over time it will reduce the potential for
dioxin releases associated with PCP-treated utility poles.
References
Lynn, Jerry, Palo Alto Purchasing Department, telephone conversation with Kelly Moran,
Palo Alto Regional Water Quality Control Plant, November 19, 1998.
National Coalition Against the Misuse of Pesticides, Poison Poles – A Report About Their
Toxic Trail and Safer Alternatives (http://www.ncamp.org/poisonpoles/ index.html),
1997.
Quarles, William, “Borates for Wood Protection,” The IPM Practitioner, Vol. XX, No. 3,
March 1998.
Thomas, Jay, and Tomm Marshall, Palo Alto Utilities Department, meeting with Kelly
Moran, Palo Alto Regional Water Quality Control Plant, December 22, 1998.
U.S. Environmental Protection Agency, Office of Research and Development, Guides to
Pollution Prevention: Wood Preserving Industry, EPA/625/R-93/014, November
1993.
3
TABLE 1: WOOD PRESERVATIVES
Name
Acronym
Medium
Applications
Notes
Pentachlorophenol
(penta)
PCP
Oilborne
Used for Douglas fir and southern pine
pilings, poles, lumber, timber,
crossarms, and fence posts. Also used
for oak and mixed hardwood crossties
and switchties. Limited use in aquatic
applications because little protection
against marine organisms; used in
freshwater.
Contains 85-90% PCP; 4-8% 2,3,4,6-tetrachlorophenol; 2-6%
higher chlorophenols; and 0.1% dioxins and furans. Commonly
supplied in 1,000-2,000 pound blocks or in solid prill or flake
form. Solid dissolved in heated fuel oil prior to use. Available
in bags or drums to facilities that use small amounts. Empty
containers considered hazardous waste. When pile driving, a
visible sheen often develops on surface water. Can now be made
“dioxin-free” but process is expensive. Performance is reliable.
Oilborne
Used for Douglas fir and southern pine
pilings, poles, lumber, timber,
crossarms, and fence posts. Also used
for marine piles, and oak and mixed
hardwood crossties and switchties.
Oily, translucent, brown to black liquid applied either full
strength or diluted with petroleum oil or coal tar. Roughly 85%
polynuclear aromatic hydrocarbons, 10% phenolic compounds,
and 5% nitrogen, sulfur, and oxygen-containing heterocycles.
Low xylene product available. When pile driving, visible sheen
often develops on surface water. Trade names include P1/P13
Creosote and Timberlife Wood Preserving Compound.
Performance is reliable.
Waterborne
Used for Douglas fir and southern pine
pilings, poles, lumber, timber,
crossarms, and fence posts. Also used
for plywood. Good for hem-fir,
western hemlock, and ponderosa pine,
but not actually recommended for
Douglas fir.
Shipped as a 50-60% concentrate and used at 1-2%. Contains
33-69% Cr(VI) as CrO3, 16-22% Cu as CuO, and 15-48% As as
As2O5. Three major formulations vary the proportions of Cu, As,
and Cr. Type C (the oxide form) is preferred. Treatment reduces
Cr(VI) to Cr(III), forming insoluble chromates. Insoluble
arsenates of Cu and Cr also precipitate. Somewhat corrosive to
untreated metal. Makes wood harder, more brittle. Reduced
bending strength, but stiffness unaffected. Strength reduced by
kiln drying; however, most not kiln dried. Available in bags or
drums to facilities that use small amounts. Empty containers
considered hazardous waste. Results in less air emissions and
leaching than PCP and creosote. Not immune to all insects and
mold. Does not penetrate heartwood, so cuts need to be sealed,
which hardly ever happens. Sold under the names Osmose and
Wolman, among others. New accelerated fixation methods have
improved its environmental credentials. Performance is reliable.
Creosote
Chromated copper
arsenate
CCA
4
TABLE 1: WOOD PRESERVATIVES (continued)
Name
Acronym
Medium
Applications
Notes
Acid copper
chromate
ACC
Waterborne
Used for hard-to-penetrate woods.
Used for lumber and plywood.
Somewhat corrosive to untreated metal.
Alkylammonium
compounds
AAC
Waterborne
Used in New Zealand.
Similar, if not the same as QAC, a primary ingredient in ACQ.
Ammoniacal
copper arsenate
ACA
Waterborne
Used for hard-to-penetrate woods.
Used for Douglas fir and other western
woods.
Among the principal inorganic arsenical compounds used to
preserve wood. Most common on the West Coast. NH3 used to
carry chemicals into untreated wood, then evaporated. If too
much NH3 remains, chemicals more likely to leach. Somewhat
corrosive to untreated metal.
Ammoniacal
copper / quaternary
ammonium
(ammoniacal
copper quat)
ACQ
Waterborne
Effective for hardwood and softwood
(including many western softwoods,
like hem-fir and Douglas fir). Limited
use in aquatic applications.
Relatively new alternative to the arsenical preservatives
(e.g., CCA). Similar to, but less toxic than, CCA. More costly
than CCA. Typical formulation is 67% copper as CuO and 33%
quaternary ammonium compounds (QAC), such as
didecyldimethyl ammonium chloride. Other formulations may
consist quat, CuO, NH3, and carbonate in ratios of
1.0:2.0:2.0:1.3.
Ammoniacal
copper-zincarsenate
ACZA
Waterborne
Used for lumber and plywood,
especially for hard-to-penetrate woods.
Used for Douglas fir and other western
woods.
Contains 45-55% Cu as CuO, 22-28% Zn as ZnO, and 22-28%
As as As2O5. Most common on the West Coast. NH3 used to
carry chemicals into untreated wood, then evaporated. If too
much NH3 remains, chemicals more likely to leach.
5
TABLE 1: WOOD PRESERVATIVES (continued)
Name
Acronym
Borates (borax,
disodium
octaborate
tetrahydrate)
Medium
Applications
Notes
Waterborne
Primarily used on timbers for log
structures and posts and beams.
Consumer products available for onsite application. Used in New Zealand
and Australia. Suitable for
aboveground uses if covered by paint
or other protective coating. Penetrates
Douglas fir, western hemlock, and dry
pine heartwood.
Commercial products just becoming available, including Boracare, Tim-Bor, Guardian, Shell-Guard, Penetreat, Impel rods,
Jecta Diffusible Boracide. Boric acid is more effective and less
soluble than disodium octaborate tetrahydrate. Protects against
fungi and wood-eating insects, but not mold or mildew. Does
not change wood color, moisture content, or structural properties.
Provides fire resistance. Does not corrode metal fasteners.
Generally non-toxic, but solubility, toxicity, and persistence
poses groundwater concerns. Penetrates heartwood. Highly
susceptible to leaching. Rods and injections take advantage of
solubility, providing protection for 3-10 years. Cannot be used to
preserve wood that will be in contact with ground or exposed to
weather. Leachate acts as herbicide. Considered safest
alternative wood treatment available.
Chloropicrin
Used in Canada, but use is rare.
Injected into poles and posts.
Chlorothalonil
Chromated zinc
chloride
Oilborne
CZC
Waterborne
In Development. Properties similar to PCP, but less toxic. Use
is inhibited by high cost. EPA-registered agricultural fungicide.
Used for hard-to-penetrate woods.
Used for lumber and plywood, but not
used much.
Copper azole
Sold by Hickson. Use is inhibited by price.
Copper citrate
CC
Copper dimethyl
dithiocarbamate
CDDC
Waterborne
Sold under name Kodiak by ISK Biosciences. Use is inhibited
by price.
6
TABLE 1: WOOD PRESERVATIVES (continued)
Name
Acronym
Copper
naphthenate
Medium
Applications
Notes
Oilborne
Sometimes used in field (over the
counter) to treat holes, cuts, or injuries
to treated products (e.g., cut ends).
Limited use in aquatic applications.
Green colored. Typical formulation is 9-19% copper
naphthenate and 81-91% inert ingredients. Costlier than creosote
and PCP. Trade names include Copper Green, Cuprinol, WittoxC, and Osmose Cop-R-Nap. Emulsified products in
development.
Little known about health effects. Generally oilborne, but a
waterborne emulsion is available. UV stable to tolerate sun
exposure.
Copper-8quinolinolate
Cu8
Oilborne /
Waterborne
Approved for wood contacting food
(e.g., wooden boxes and pallets).
Available commercially for log homes,
wood siding, and shake shingles.
Fluor chrome
arsenate phenol
(fluorine / chrome /
arsenic /
dinitrophenol)
FCAP
Waterborne
Not used much.
Folpet
Iodopropynyl
butylcarbamate
IPBC
Oilborne
Commercial products.
Suspected carcinogen.
Dipping exterior millwork.
Application has replaced PCP. Found
in exterior paints and stains.
Emulsified products in development.
Metam-sodium
Used in U.S. and Canada, but use is
rare. Injected into poles and posts.
Sodium tetra and
pentachlorophenate
Used commercially in Canada.
2-(thiocyano
methylthio)
benzothiazole
TCMTB
Used commercially in Canada.
7
Little known about health effects.
TABLE 1: WOOD PRESERVATIVES (continued)
Name
Acronym
Medium
Applications
Notes
Tributyl tin oxide
(bis [tri-n-butyltin]
oxide)
TBTO
Oilborne
Used for consumer applications.
Found in exterior paints and stains.
Sold as paint additive.
Emulsified products in development. Toxic to fish.
Used around 1920s.
Leaches and acid can weaken wood. Replaced commercially by
CCA. Techniques that convert zinc chloride to insoluble zinc
hydroxide are being studied and have shown some success.
Sometimes used in field (over the
counter) to treat holes, cuts, or injuries
to treated products (e.g., cut ends).
Clear; not green colored. Emulsified products in development.
Zinc chloride
Zinc naphthenate
Oilborne
Zinc sulfate
Waterborne
Source: Attachment A
8
ATTACHMENT A
Notes Regarding Wood Preservatives and
Alternatives to Pentachlorophenol
U.S. Environmental Protection Agency, Office of Research and Development, Guides to
Pollution Prevention: Wood Preserving Industry, EPA/625/R-93/014, November 1993.
Preserved wood is used primarily in the construction, railroad, and utilities industries to prevent
rotting when wood is exposed to damp soil, standing water, or rain, and as protection against
termites and marine borers. Approximately 600 million cubic feet of wood are treated with wood
preservatives and fire retardants each year. In 1988, the total cubic feet of wood treated with PCP
was 47,870,000; with creosote solutions (i.e., creosote, creosote-coal tar, and creosote-petroleum)
was 90,482,000; with waterborne preservatives (i.e., chromated copper arsenate [CCA],
ammoniacal copper-zinc-arsenate [ACZA], acid copper chromate [ACC], and chromated zinc
chloride [CZC]) was 450,566,000; and fire retardants was 10,230,000.
Creosote and PCP are the major oilborne preservatives and are primarily used for older processes,
such as treating crossties, crossarms, and utility poles. The most common waterborne
preservatives are CCA and ACZA. Creosote is an oily, translucent, brown to black liquid applied
either full strength or diluted with petroleum oil or coal tar. It contains roughly 85% polynuclear
aromatic hydrocarbons (PAHs), 10% phenolic compounds, and 5% nitrogen, sulfur, or oxygencontaining heterocycles. Technical grade PCP contains 85-90% PCP, 4-8% 2,3,4,6tetrachlorophenol, 2-6% higher chlorophenols, and 0.1% dioxins and furans. CCA is shipped as a
50-60% concentrate and used at 1-2%. CCA formulations contain 33-69% chromium(VI) as
CrO3, 16-22% copper as CuO, and 15-48% arsenic as As2O5. ACZA contains 45-55% copper as
CuO, 22-28% zinc as ZnO, and 22-28% arsenic as As2O5.
Waterborne preservatives produce less waste than oilborne preservatives because process water
can be reused. Alternative preservatives have been proposed. They include borates; however,
borates are highly susceptible to leaching; therefore, they are not well suited to preserve wood
that will be in contact with the ground or exposed to the weather. Ammoniacal copper/quaternary
ammonium (ACQ) may be effective for softwood and hardwood protection. Other alternatives
may include copper-8-quinolinolate (Cu8), copper naphthenate, quaternary ammonium
compounds (QAC), and zinc sulfate.
Wood Preserving Fact Sheet EPA/530-SW-90-027f.
(http://es.epa.gov/techinfo/facts/preserve.html)
Ammoniacal copper arsenate (ACA) is another inorganic arsenical compound principally used to
preserve wood.
U.S. Environmental Protection Agency, Enforcement and Compliance Assurance, Profile of
the Lumber and Wood Products Industry, EPA 310-R-95-006, September 1995.
Alternatives may also include zinc naphthenate.
A-1
Noyes, Robert, ed., Pollution Prevention Technology Handbook, Park Ridge NJ: Noyes
Publications, 1993.
When applied, PCP is dissolved in a petroleum-based solvent. The species of wood to be treated
often dictates the preservation technique used. Douglas fir and southern pine (pilings, poles,
lumber and timber, crossarms, and fence posts) can be treated with creosote, PCP, or CCA. Oak
or mixed hardwood (crossties and switchties) are commonly treated with creosote or PCP only.
CCA tends to make wood harder or more brittle; therefore, its use may sometimes be
inappropriate. About 90% of wood preservatives are in the form of chrome/copper arsenate;
therefore, the wood-preserving industry accounts for 20% of all arsenic consumption.
PCP is commonly supplied in 1,000-2,000 pound blocks or in solid prill or flake form. Solid PCP
is dissolved in heated fuel oil prior to use on site. PCP and CCA are available to facilities that
use small amounts of preservatives in bags or drums. When emptied, containers are considered
hazardous waste as a result of the residual waste in the containers; therefore, bulk shipments are
preferable.
Western Wood Preservers Institute and Canadian Institute of Treated Wood, Best
Management Practices for the Use of Treated Wood in Aquatic Environments, USA version,
revised January 1995.
Users of treated wood can specify that the wood they buy is produced in compliance with the
Western Wood Preservers Institute BMPs and require assurances that this is true. On-site
inspection prior to installation is recommended. A BMP identification mark is being or has been
developed. Projects calling for large volumes of treated wood immersed in poorly circulating
water bodies should be evaluated individually using risk assessments.
Low xylene creosote is available. When driving creosote piling, a visible sheen of creosote often
develops on the surface water.
CCA is good for hem-fir, western hemlock, and ponderosa pine, but probably not Douglas fir. In
the CCA treatment process, hexavalent chromium is reduced to trivalent chromium with the
formation of a complex mixture of insoluble chromates. Insoluble arsenates of copper and
chromium are also precipitated in the treated wood. ACZA and ACA can be used to treat
Douglas fir. These processes are most common on the west coast. In the ACZA and ACA
processes, ammonia is used to carry the chemicals into the wood. Then the ammonia is
evaporated. If too much ammonia remains, then the treatment chemicals are more likely to leach
when placed in an aquatic environment.
Ammoniacal copper quat (ACQ) has limited use in aquatic (particularly saltwater) applications.
ACQ is good for many western softwoods, like hem-fir and Douglas fir. Dual treating means
treating with waterborne preservative (e.g., CCA, ACZA, or ACA) and then treating with
creosote. It is needed for particularly aggressive marine organisms, which are typically located
on the Pacific Coast south of San Francisco.
Copper naphthenate has limited use in aquatic applications. It is sometimes used in the field to
treat holes, cuts, or injuries to treated products. Copper naphthenate is an oilborne preservative.
PCP has limited use in aquatic applications because it does not protect against marine organisms,
but is used in freshwater. When driving PCP-treated wood, a visible sheen of PCP may appear on
the water surface.
A-2
The Fixation of Ammoniacal Copper Preservatives.
(http://www.forestry.ubc.ca/brchline/96sept/page3.html)
The fixation of ammoniacal copper systems were thought to be based on the precipitation of
copper as the ammonia evaporates. Studies indicate that, in addition, stable diammine copper(II)
complexes are formed between the copper and the heartwood extractives, such as taxifolin in
Douglas fir.
Sustainable Building Sourcebook: Wood Treatment.
(http://www.greenbuilder.com/sourcebook/WoodTreatment.html)
Copper naphthenate, zinc naphthenate, and tributyl tin oxide (TBTO) are alternatives that can be
applied on site. CCA does not penetrate heartwood effectively, so a sealer is recommended on
cut ends of CCA-treated wood. Hardly anyone does this. Borates are less toxic and are derived
from borax. Borates are used in New Zealand and Australia. Borate products can be applied on
site. Borates penetrate heartwood. ACQ is a new alternative that is less toxic than CCA and
performs similarly. ACQ costs more than CCA.
Decay resistant domestic woods include cedar, redwood, bald cypress (old growth), catalpa, black
cherry, chestnut, Arizona cypress, junipers, black locust, mesquite, red mulberry, burr oak,
chestnut oak, gambrel oak, Oregon white oak, post oak, white oak, osage orange, sassafras, black
walnut, Pacific yew.
Smulski, Stephen, Building Materials and Wood Technology, University of Massachusetts
at Amherst, “Preservative Treated Wood.”
(http://www.umass.edu/bmatwt/preserv.html)
Wood freshly infused with creosote gives off potentially harmful vapors that eventually
disappear. Oilborne preservatives are carried in organic solvents, such as liquified isobutane.
They include PCP, iodo propynyl butyl carbamate (IPBC), copper and zinc naphthenate, and
TBTC. Urethane, latex enamel, shellac, and varnish effectively seal PCP treated wood. Until
1985, exterior millwork was dipped in PCP in light oil. With safer solvents, IPBO has replaced
PCP in this application. Copper naphthenate is the ingredient in green-colored do-it-yourself
products; zinc naphthenate is in the clear products. Most exterior paints and stains already
contain IPBC or TBTO. TBTO is sold separately as a paint additive. Water-based emulsions of
these preservatives are under development.
Fluor chrome arsenate phenol (FCAP) is a waterborne preservative with chemistry similar to
CCA, ACA, ACC, CZC, and ACZA. Chromium helps hold the other components tightly to the
wood to prevent leaching, which is minimal. CZC and FCAP are not used much. Zinc and
copper fight fungi, and arsenic fights termites and copper-resistant fungi. Douglas fir and other
western woods are commonly treated with ACA and ACZA. CCA is usually used on southern
yellow pine. CCA has three basic formulations. Type C (oxide form) is preferred. CCA is
gaining ground on PCP and creosote in the pole markets because of its effectiveness and relative
safety. At playgrounds, water repellent or oil-based stain or paint is recommended to lessen
potential for skin contact. Because wood is water saturated during treatment and seldom kiln
dried, wood should dry for at least a week before applying water repellents, stains, or paints. The
copper in CCA, ACA, an ACC is corrosive to uncoated metal. CCA decreases the bending
strength of southern pine, although stiffness is unaffected. Most strength reduction results from
kiln drying.
A-3
Borates (e.g., disodium octaborate tetrahydrate) protect wood from most fungi and wood-eating
insects. Borates do not affect the color of the wood. They are noncorrosive to fasteners and can
be readily glued and finished. Borates are also nontoxic to animals and humans, and increase
wood’s fire resistance. Borates are primarily used to treat timbers for log structures and post and
beam construction. The problem is that borates remain water soluble; therefore, they readily
leach from wood when it gets wet. Leaching from exterior walls of log homes is all but
eliminated by applying water repellant every couple years.
Future alternatives include chlorothalonil, an EPA-registered agricultural fungicide. It performs
like PCP, but costs much more. Waterborne alkylammonium compounds (ACC) are used
commercially in New Zealand.
Nadav Malin.
(http://www.ebuild.com/Greenbuilding/Poles.html)
Recycled plastic is being used to make “lumber” products, but most of the products are not very
strong.
International Conference of Building Officials, Ammoniacal Copper Quat (Acq) Preserve
System for Preservative Treatment of Wood by Pressure Process.
(http://www.icbo.org/ICBO_ES/Acceptance_Criteria/pg-AC_078.html)
ACQ contains copper (II), carbonate, ammonia, and a quaternary ammonium compound (quat),
didecyldimethylammonium chloride. The ratio of copper (expressed as CuO) to quat is about 2:1.
The ratio of ammonia (expressed as NH3) to CuO is at least 1:1. The ratio of carbonate
(expressed as CO2) to CuO is at least 0.65:1.
Woodguard.
(http://www.woodguard.com/GeneralInfo.html)
Cu8 is available commercially. It is designed for log homes, wood siding, and shake shingles. It
is UV stable so it does not break down in sunlight.
Florida Agricultural Information Retrieval System: Wood and Metal Preservatives.
(http://128.227.103.58/txt/fairs/43453)
Cu8 is available in two formulations: one that uses an organic solvent and one that can be mixed
with water. The latter eliminates some fire hazard. Cu 8 is used on wooden boxes and pallets.
Wood Treatment – The Canadian Perspective.
(http://www.ns.ec.gc.ca/epb/factsheets/wood.html)
In Canada, the most common wood preservatives are PCP, creosote, CCA, and ACA. The major
chemicals used commercially are sodium tetra and pentachlorophenate, Cu8, and 2(thiocyanomethylthio) benxothiazole (TCMTB). Little health research has been done on Cu8 and
TCMTB. TCMTB can cause skin and eye irritation if improperly handled. Several other
chemicals are under review. Other products registered in Canada but less frequently used include
bis (tributyltin) oxide (brushed on cut ends of pressure treated lumber and in marine paints),
copper and zinc naphthenate (used to treat cut ends), and metam-sodium and chloropicrin
(injected into poles and posts).
A-4
CCA is used for fence posts, patio and landscape lumber, foundation lumber, plywood, shingles
and shakes, and siding. ACA is used for utility poles, fence posts, and construction and
landscaping timbers. PCP is used for railroad ties, utility poles exterior paints and stains, and
construction timbers and posts. Creosote is used for railroad ties, marine pilings and timber, and
other construction timbers. Chlorophenates, Cu8, and TCMTB are used for structural lumber for
export.
American Wood Preservers Institute, Selected Acronyms & Abbreviations for Wood
Products, Forest Industry & Government Affairs.
(http://www.awpi.org/acronyms.html)
Copper Citrate (CC)is another wood preservative.
Treated Wood Products Available in Missouri.
(http://muextension.missouri.edu/xplor/agguides/forestry/g05505/htm)
Consumers should not confuse treated wood products with products dipped in oil or tar solutions,
which are not wood preservatives. The procedure is cosmetic, giving the wood a dark color
similar to PCP treatment. Products dipped in oil or tar include oak ties used in building retaining
walls.
SRI Consulting, Wood Preservatives – U.S.
(http://www.cmrc.sri.com/CEH/Reports/Wood_Preservatives_US.html)
In May 1996, SRI published a report called “Wood Preservatives – US,” written by Fred Stahl. It
consists of a 28-page data summary for sale for $500. It discusses creosote, oilborne
preservatives (e.g., PCP and copper and zinc naphthenate, waterborne preservatives (e.g., CCA),
and consumer market preservatives (e.g., copper and zinc naphthenate, and tributyltin oxide).
National Coalition Against the Misuse of Pesticides, Poison Poles – A Report About Their
Toxic Trail and Safer Alternatives, 1997.
(http://www.ncamp.org/poisonpoles/index.html)
Some alternatives to treated poles include recycled steel (apparently preferred), reinforced
concrete, and fiberglass reinforced composite. Another alternative is burying utility lines,
although this requires chemical treatments to protect the lines from decay and pests.
There are three kinds of creosote. One results from high-temperature treatment of coal, one from
high-temperature treatment of beech and other woods, and one from the resin of the creosote
bush. Coal-tar creosote is the most common in the U.S. Trade names include P1/P13 Creosote
and Timberlife Wood Preserving Compound. CCA is used under the names Osmose and
Wolman, among others. A typical copper naphthenate formulation would be 19% copper
naphthenate and 81% inert ingredients. The copper naphthenate portion is poorly characterized.
Trade names include Cuprinol, Wittox-C, and Osmose Cop-R-Nap.
A-5
Meehan, Donald B., Island County Extention Agent (Wisconsin), “EPA Restricts Use of
Wood Preservatives.”
(http://www.island.wsu.edu/tt_62.htm)
Treated lumber must be marked to indicate the type of chemical and process used. Most
commonly, the trade name for a process appears (e.g., Wolmanized, Celcure, or Chemonite). If
properly labeled, CCA-treated lumber will have the letters “CCA” stamped on it. The Wisconsin
Extension has a publication that explains what the letters mean: “Preservative Treatment of
Wood for Farm Use.” It is available for a small fee.
Lawrence Cookson, CSIRO, Forestry and Forest Products, transmittal, October 6, 1996.
PCP can now be made dioxin free, but the process is prohibitively expensive. Alternative
preservatives include ACQ, copper-azole, CDDC, and chlorothalonil. The first three are CCA
alternatives, but still contain copper. ACQ (ammoniacal copper quaternary ammonium
compound) is sold by CSI (contact Drs. Alan Preston and Kevin Archer in Charlotte, North
Carolina, at [email protected] and [email protected]). Copper-azole is a Hickson
product. CDDC is copper dimethyldithiocarbamate and is sold under the name KODIAK in
South Carolina by ISK Biosciences (try contacting Dr. Joe Ignatoski, PO Box 9158, Memphis,
Tennessee 38109). ISK has also developed chlorothalonil for wood preservation. It is similar to
PCP, but has much lower toxicity. It is used as a fungicide on food crops. Chlorothalonil is not
commercially available as a wood preservative because it is more expensive than PCP or
creosote.
Some reasons for continued use of CCA and creosote are price and performance reliability. New
accelerated fixation methods for CCA have improved its
environmental credentials.
Zinc chloride is an old preservative used commercially around the 1920s, but it can leach and the
acid can weaken wood. For these reasons, CCA has largely replaced it. There are, however,
ways to turn zinc chloride into insoluble zinc hydroxide in wood. A five year marine test of this
treatment has performed well.
Washington Toxics Coalition, “Alternatives: A Washington Toxics Coalition Fact Sheet,”
November 1994.
Folpet and TBTO are used in commercial products. Folpet is a suspected carcinogen. TBTO is
toxic to fish at ppt level and is banned in many states. Arsenic-containing preservatives should
not be used on wood used for cutting boards or counter tops. Copper naphthenate, zinc
naphthenate, and Cu8 are among the least acutely toxic preservatives; however, their long-term
health effects have not been studied. The U.S. Food and Drug Administration has approved Cu8
where food contact may occur. Wood treated with Borax has become available. Copper, zinc,
and borax are usually not effective in soil contact situations.
In many cases, paint or clear finish provides all the moisture protection needed without pressure
treatment. Wood rot can be avoided by providing ventilation and by raising the wood away from
soil. Cedar, redwood, and cyprus naturally resist weather and rot; however, most of this wood is
cut from old growth forests. Second growth timber is apparently less weather resistant. Concrete
blocks, ceramic tiles, recycled plastic, and replaceable scrap wood can be used in gardens.
A-6
“If you must use a wood preservative, choose the safest one possible. For soil contact, away from
food, lumber treated with an arsenical may be called for. If there is no soil contact, wood treated
with copper, zinc, or boric acid is probably safer.”
William Quarles, “Borates for Wood Protection,” The IPM Practitioner, Vol. XX, No. 3,
March 1998.
Boric acid (H3BO3) and its salts (e.g., borax, Na2B4O7) have been used in Australia since the
1940s. Borates with greater water solubility than borax include disodium octaborate tetrahydrate
(DOT, Na2B8O13∃4H2O). Commercial products include Bora-Care (liquid 40% DOT
concentrate), Tim-Bor (98% DOT powder used to dust attics and wall voids, and to dissolve in
water), Guardian, Shell-Guard, Penetreat, Impel (rods of solid fused borate dropped in holes to
dissolve and permeate with moisture), Jecta Diffusible Boracide (40% sodium borate gel). Borate
fogging has been replaced by borate foams, which are more effective.
Borate solutions protect against wood boring beetles, subterranean termites, drywood termites,
Formosan termites, carpenter ants, and wood decay fungi. Only treated wood is protected, but
termites are reluctant to “tube over” treated areas, perhaps because the boron readily diffuses
through the moist soil tubes. Borates are not contact repellents; they kill by contact. Boric acid
more effectively kills on contact than DOT. Borates do not protect from molds and mildew.
Boric acid is generally more effective against wood decay fungal species than other fungicides,
except TBTO and fluorine / chrome / arsenic / dinitrophenol. Borate treated hardwoods are less
protected than treated softwoods.
Borates can be applied with dip treatments or short pressure treatments even with refractory wood
such as Douglas fir and western hemlock. Solutions in ethylene glycol best penetrate dry wood,
diffusing up to one inch, even in the case of dry pine heartwood. Poles in contact with water
wick water out of the ground, resulting in a water flow in the wood up the pole and out into the
air. Soluble substances, such as borates, follow this flow. Impel rods take advantage of the
solubility of borates, lasting 3-10 years in consistently wet conditions. An effective dose can
travel 4-5 inches in 9 months. Borates leach out when in contact with wet solid.
Borates do not discolor wood, are odorless, and do not evaporate. They do not cause wood to
absorb water or change the equilibrium moisture content of the wood. Borates penetrate when
painted on, unlike other more toxic materials. Borates do not affect the structural properties of
wood, and fasteners (like nails) are not corroded. If covered by paint or other protective coatings,
wood is suitable for most above-ground uses. Treated wood is also fire retardant.
Borates are moderately toxic and persistent and, therefore, can result in groundwater
contamination, especially if used by many people at once. Zinc borate is nearly insoluble, so it
could be used as a toxic barrier around fence posts. Borates are also herbicides. The primary
danger to humans from borates is chronic unprotected exposure to aerosols or accidental acute
ingestion of large amounts. Borates do not cause cancer, have low toxicity, do not cause skin
allergies by contact, and are generally safe. Borates are considered the safest and most effective
wood protective treatment available.
A-7
ATTACHMENT B
Alternatives To Wood Poles
an excerpt from
Poison Poles - A Report About Their Toxic Trail and Safer Alternatives
(National Coalition Against the Misuse of Pesticides 1997)
…No comparative analysis of products would be complete without consideration of the cost
differential among them. Sometimes the analysis is skewed by its failure to consider the
differential in the life span of a product. It is also biased by a failure to consider external
pollution costs relating to chemical cleanup and health care associated with a wood
preservative-induced illness.
In the case of wood, the utility industry expects 40 to 50 years of service (although it has
been found that a bad batch of wood can yield less than 35 years of service). The steel,
concrete and fiberglass alternatives yield a lifespan of 80 to 100 years. There are differences
in maintenance costs associated with different materials. Wood may require retreatment, as
some utilities do on a set cycle, while steel, concrete and fiberglass do not. In addition,
disposal costs for chemicals used in wood treatment are high and growing, while steel is
recycled.
Below is a discussion of the major alternative materials to chemically treated wood utility
poles. It is important to consider these issues in the context of making a choice that is better
for the environment and public health.
Recycled Steel
Steel has been cited as the most common alternative utility pole material in a Swedish
report.1 The same is true in the United States, although steel and all the alternatives represent
a small but growing alternative when compared with the use of treated wood utility poles.
The steel industry identifies steel as "the world's, as well as North America’s, most recycled
material, and in the United States alone, over 70 million tons of steel were recycled in 1995,
resulting in an overall recycling rate of 68.5 percent."2 The industry says that two out of
every three pounds of new steel are produced from old steel. Two processes are used. The
basic oxygen furnace (BOF) process or blast furnace, which uses 28 percent scrap steel, and
the electric arc furnace (EAF) process, which uses 100 percent scrap metal. The steel for
utility poles are made with the electric arc furnace.3 According to the industry, when one ton
of steel is recycled the following is conserved: 2,500 pounds of iron ore, 1,400 pounds of
coal and 120 pounds of limestone.4
The Swedish report indicates that air pollution associated with the processing phase of steel is
the predominant type of pollution in the processing life cycle phase.5 The report identifies a
drastic reduction in air pollution from 1970 to 1988. Emissions to the air dropped in the
following ways: dust, containing a number of metals, such as lead, copper and cadmium,
B-1
went from 150,000 ton/year to 5,000; sulphur dioxide from 32,000 to 8,000 ton/year;
nitrogen oxide from 4,400 to 3,700 a year and carbon dioxide from 8.0 x 10-6 to 4.4 x 10-6.
While steel production has been cleaned up considerably over the past decade, environmental
concerns focus on air and water pollution. The electric arc furnace, a cleaner process than the
oxygen furnace, still produces dust contaminated with metals that are classified and disposed
as hazardous waste. The production process also produces a sludge that can be landfilled and
discharge water that can be sent to a municipal water treatment facility. Nucor, which uses
EAF technology to produce new steel from recycled scrap metal for at least two steel pole
manufacturers, released less than 100 pounds of lead in 1995 in producing approximately 1.5
million tons of steel.6 While little research has been done on U.S. steel plants, there have
been European studies that find airborne dioxin emissions associated with steel product in
iron sintering plants, which are adjuncts to blast furnace operations. The contaminants are
tied to the use of chlorinated lubricants in the operations and could be eliminated with
changes in practices.7
The Swedish report credits steel poles with a life of approximately 80 years and indicates that
the reuse rate "almost reaches 100 percent, resulting in a reduced energy utilization in the
processing phase from 10,000 kWh/ton to 1,700 kWh/ton.8 The steel utility poles are either
galvanized or coated with a sealant.
International Utility Structures, Inc. (IUSI) in Baceville, AR and Valmont Industries in
Valley, NE have gotten into the steel utility pole business in the last several years. For a 40
foot, class 3 pole, they both have competitive pricing with IUSI pricing at $2659 and Valmont
at $31510 (exclusive of freight). Valmont’s 40 foot, class 4 pole, which has a thinner diameter
than the class 3, is approximately $260.11 IUSI produces a 40 foot, class 5 pole and charges
$215.12 The material is lighter in weight than wood and the installation is similar.
Concrete
Reinforced concrete is also identified as an alternative material to treated wood poles.
Centrifugal casting is used to produce concrete poles with natural gravel or crushed stone
with steel reinforcement. The environmental issues related to cement, the “glue” that holds
concrete together, raises serious environmental issues that must be added to the concerns
about steel raised above. The material's longevity ranges from 80 to 100 years.13
Cement is produced in kilns that often burn hazardous waste. By 1994, 37 facilities out of
111 plants in the U.S. were permitted to use hazardous waste as a fuel to replace some or all
of the large amounts of fuel required.14
Cement is made by heating limestone, clay, and other materials to very high temperatures to
form "clinker," which is cooled and ground with gypsum to make cement. This is
accomplished by circulating the combustion gas around raw materials in a kiln. Many of the
constituents of the vapor become part of the clinker or cement kiln dust.15
About 60 percent of the five million tons of hazardous wastes incinerated annually is burned
in boilers and industrial furnaces, almost all of the cement kilns or lightweight aggregate
kilns. About 90 percent of all commercially incinerated liquid hazardous waste in the U.S.,
as well as a growing percentage of solid hazardous waste, is burned in cement kilns.16
B-2
Some of the wastes burned in cement kilns are destroyed, but some are indestructible (heavy
metals) and some are transformed into more toxic chemicals like chlorinated benzenes and
dioxins. Everything which is not destroyed is released into the environment in some way.
Some is released through fugitive emissions from the stacks in gaseous particulate form.
Some is adsorbed to cement kiln dust, which is typically piled on the ground before being
taken to conventional landfills. Some is left in the ash, which also goes to landfills. And
some becomes part of the cement-to be breathed daily by those living near "ready-mix"
plants, and to be slowly released into the environment from concrete….17
Therefore, while concrete poles are an alternative that may be preferable to wood in many
cases, the current practice of producing cement through the burning of hazardous waste raises
serious environmental pollution problems. Furthermore, concrete construction material is
normally not used as a raw material for another product, although techniques exist for reuse.
StressCrete, a company based in Burlington, Ontario, Canada (with a plant in Tuscaloosa,
AL) is a major producer of cement utility poles. It charges $375 for a 40 foot, class 3 pole
and $350 for a 40 foot, class 4 pole (exclusive of freight). Because of its weight its
installation costs tend to be higher than other alternatives. However, its durability is proven,
having a track record of surviving hurricanes in the southeastern U.S.18
Other Alternatives
There are a number of other materials that are available for poles as well as the option of
burying utility lines underground. The other pole material that most commonly surfaces is
made from fiberglass reinforced composite (FRC). The manufacturing process is described
by the major manufacturer of the product, Shakespeare, in Newberry, South Carolina, as
follows:
These new fiberglass reinforced composite utility poles are manufactured using
the filament winding process.... Filament winding is accomplished on a machine
which winds glass fibers onto a mandrel in a prescribed pattern to form the
desired finished shape.... For filament winding, fiberglass is purchased in a
yam-like form called roving. This roving is routed through a bath of liquid,
catalyzed, pigmented, polyester resin before it reaches the mandrel.
After the fiberglass and resin are in place, a surface of resin impregnated nonwoven polyester fabric is applied. Heat is then applied to initiate cross linking
(hardening) of the resin. After hardening, the tube is removed from the
mandrel.... After the tube is removed from the mandrel, it is trimmed to length
and any required holes are drilled.… The final step is the application of a
pigmented polyurethane topcoat.19
Burying utility lines is often considered as an option for aesthetic reasons or in areas [where]
utility or telephone companies are trying to avoid severe weather conditions. Although cost
is a major consideration, the burying of lines is currently accompanied by the use of chemical
treatments to protect lines from decay and pest problems…. The use of…chemicals buried
along rights of ways, over water tables and in sensitive areas, represents a serious threat to
environmental protection.
B-3
Shakespeare prices its 40 foot, class 4 poles at $900….20
Cost Comparisons
It is difficult to compare costs of treated wood poles and the principal competition, steel,
because of a number of factors that vary, including the type of wood utilized, maintenance
practices, and length of service. Although Southern Yellow Pine is the most common wood
utilized, Douglas Fir and Western Red Cedar are used in the West. Utilities use different
average size poles, most [about] 40 foot poles with differing thickness that are generally
either class 3 or class 4. In addition, pole prices vary according to a number of factors
including volume purchases, contract agreements and volatility of the market.
Nonetheless, the purpose of this section is to generate a cost comparison between chemically
treated wood poles to provide a context for evaluating the competitiveness of the alternatives.
Tillamook People's Utility District, Tillamook, OR 9714121
This utility service area covers 60 miles of Pacific coastline and 24,000 poles. The utility
uses coastal Douglas Fir, with an average pole size of 40 foot, class 4. It pays $271 for its
penta-treated wood poles and approximately $70 more for steel poles. The utility district is
purchasing steel poles currently for aesthetic reasons and to use in high traffic areas where it
is expected that they will have less maintenance requirements. The utility indicates that there
is some maintenance savings associated with the steel poles because they can discontinue the
wood pole retreatment program which costs the utility $30 to $35 a pole. The utility retreats
poles on a ten-year rotational cycle, treating the poles with additional chemicals
(chloropicrin) as a preventive measure to stop decay before it starts. The utility believes that
steel provides a long-term savings because its lifespan, estimated at 80 years, is double that
of wood. They base this estimate on their experience with galvanized steel substations,
transmission towers and fences. They also believe that they will recoup some of the cost of
the steel pole through salvage at the end of the life of the pole.
Public Utility District of Douglas County, East Wenatchee, WA 9880222
This utility services north central Washington state. The utility uses on average a 40 foot,
class 3, Western Red Cedar pole that is treated with penta only on the portion of the pole that
is submerged underground. The cedar is naturally resistant to insects and decay. An
inspection program is conducted on a 10-year cycle with treatment on an as needed basis.
The utility has begun using steel poles. It pays $360 for wood poles and $383 for steel.
Eastern Utility Association, West Bridgewater, MA 0237923
The utility covers a 599 square mile area in Massachusetts. The utility uses on average a 40
foot, class 4, Southern Yellow Pine pole, full length treated with pentachlorophenol. It pays
on average $213 a pole and does not purchase any other alternative materials.
Pennsylvania Power & Light, Allentown, PA 1810124
This public utility has a service area that includes 23 counties in northeastern Pennsylvania,
10,000 square miles and 54,000 miles in their distribution system. The company uses full
B-4
length creosote-treated Southern Yellow Pine poles. It pays $249 for its standard 45 foot,
class 3 pole. The utility discontinued its retreatment program as part of a budgetary move.
However, previously the utility conducted a pole retreatment program every five years,
treating poles from three feet above groundline to the base.
City of Alliance, Alliance, NE 6930125
This municipal utility covers 140 square miles in west central Nebraska. The area takes in
250 miles. of primary distribution line. The utility is currently using full length penta-treated
Douglas Fir for which it is paying $312 for its average 40 foot class 3 pole. It also uses full
length penta-treated Western Red Cedar, depending on the price. The [city] does not have a
retreatment program.
Conclusion
From a cost perspective, alternatives to treated wood poles have become more competitive in
recent years. Steel and concrete appear to be more cost competitive at this time than
fiberglass. Longer transportation distances for wood pole alternatives add an additional front
end cost to the alternative materials. However, savings in maintenance, longer in service
lifespan and salvage value (of steel in particular) levels the cost playing field over the longterm.
Cost issues aside, there are numerous compelling reasons for shifting away from the
hazardous chemicals used in treating utility poles and moving to alternative pole materials.
While there are a range of considerations that should be brought into play, as indicated in this
chapter, there is every reason to begin moving away from the use of pentachlorophenol,
creosote, copper chromated arsenate and other wood preservatives.
ENDNOTES
1
Erlandsson, M. et al., 1992. Environmental consequences of various materials in utility poles - A life
cycle analysis. The International Research Group on Wood Preservation. Stockholm, Sweden. Paper
prepared for the 23rd annual meeting.
2
Steel Recycling Institute, 1996. The Inherent Recycled Content of Today’s Steel.
3
David Sulc, Environmental Engineer, NuCor, Crawfordsville, IN. Personal Communication. January 6,
1997.
4
Steel Recycling Institute, 1996. Buy Recycled with Recyclable Steel.
5
Erlandsson, 1992. p.4-5.
6
Sulc, 1997.
7
Holger, Environmental Scientist, Center for the Biology of National Systems, Queens College, Flushing,
NY, personal communication, January 6, 1997; H. Eisl, 1996. Zeroing Out Dioxin in the Great Lakes:
Within Our Reach, Center for the Biology of Na tural Systems, Queens College, Flushing, NY, June, 1996.
8
Erlandsson, 1992. p.5.
9
Bob Jack, International Utility Structures, Inc. Pesonal communication. January 3, 1996
10
Tom Sanderson, Valmont Industries, personal communication. January 3, 1996.
11
Ibid.
12
Jack, personal communication.
13
Erlandsson, 1992. p.7.
14
Environment Protection Agency, 1994. Application of Enhanced Public Participation and Stronger
Combustion Permitting Requirements. Memorandum document number 53 0-F-94-017. May 23, 1994 as
B-5
cited in M.A. Richardson, 1995. Recycling or Disposal? Hazardous Waste Combustion in Cement Kilns,
American Lung Association, Lansing, MI and Washington, DC.
15
Stuart A. Batterman and Yuli Huang. Evaluation of the Screening Analysis for the Texas Industries
Facility in Midlothian, Texas. American Lung Association of Texas. May 1, 1996.
16
Edward Kleppinger, Cement clinker: an environmental sink for residues from hazardous waste treatment
in cement kilns, Waste Management 13: 553-572, 1993. Cited in Richardson, 1995.
17
M.A. Richardson, 1995.
18
Garry Bradford, Vice-President, Sales & Marketing, StressCrete Limited. Personal Communication.
January 2, 1996.
19
Shakespeare. Company literature. undated.
20
G. Lynn Derrick, Vice President, Sales & Marketing, Shakespeare Products Group. Personal
Correspondence. November 15, 1996.
21
John Hawarth, Engineering Manager, Tillamook People’s Utility District, Tillamook, OR. personal
communication. December 1996.
22
Mitch Hawkins, Distribution Engineer, Public Utility District of Douglas County, East Wenatchee, WA,
personal communication. December 1996.
23
Helen Palmer, buyer, Eastern Utility Association, West Bridgewater, MA, personal communication.
January 2, 1997.
24
Barry Stocker, Procurement Analyst, Pennsylvania Power & Light, Allentown, PA. personal
communication. December 1996.
25
Steve Stone, Electric Superintendent and Betty Irish, Assistant Store Keeper, City of Alliance, Alliance,
NE. personal communication. December 1996.
B-6