The analyses show that some surface salts are present and there
are greater quantities of trace metals on the ACA treated wood in
comparison with the CCA material. This data suggests possible
skin contamination problems if the freshly treated dried wood is
handled directly without gloves.

Non-Pressure Treating Plants and Processes
Description of Industry and Common Factors --

Wood products to be treated by the thermal non-pressure process
must be pre-dried to a satisfactory moisture level. Poles
typically take six months to a year for air drying (the most
common product treated). Generally, poles are received at
plants peeled and partially seasoned. In some instances,
debarking is required. Prior to treatment, a final peeling is
done, followed by incising, drilling or framing to customer
specifications. Incising is a treatment to improve penetration
of the preservative chemical by compressing with a spiked

wheel to produce a series of small holes of uniform depth and
distance along the length of the wood. Visual inspection and
manual cleanup with draw knives are done to remove rot areas
and residual bark.

The poles are loaded into full-length or butt treatment tanks
with cranes or custom forklift equipment. Usually it requires
the assistance of several yard personnel. During unloading of
treated wood, workers can be exposed to the preservative
chemicals via inhalation or skin contact.

Poles treated in full-length tanks are held in place with steel
cross beams. The tanks are covered with steel plates prior to
flooding the tank with hot oil solution to initiate the treatment
phase. Butt dip tanks open during the treatment cycle but only
limit oil surface area between poles is exposed to emit fumes.

After treatment is completed,the hot oil solution is pumped to
storage for reuse. Poles are inspected and checked by quality
control personnel to determine preservative penetration and
-concentration. The inspections and borings are conducted by
either a plant employee or a utility company representative or
both. It can be done either in the tank after it is drained
or outside on truck, railcars,or in the storage yard.

Thermal treating with pentachlorophenol usually takes over night.
The total treatment cycle for the only creosote thermal process
surveyed is approximately two days. Loading tasks are essentially
identical for both materials.

The limited commercial use of the vacuum non-pressure process
permitted the inclusion of only one treatment plant utilizing
this method in the preliminary phase of the study. At this
facility, partially air-dried dimensional lumber. is treated
with 5% PCP/petroleum oil in a vacuum chamber at ambient
temperature. The length of the treatment cycle is determined by

55


ACA, which is typically formulated from the basic raw materials
at the plant, is used at elevated temperatures and airborne
exposure from the mixed material will occur. However, there
are only a limited number of plants where ACA is used. ACA is
blended at the plant by the addition of copper oxide to arsenic
acid solutions in a mix tank. After these two materials are
blended, aqueous ammonia solution is pumped to the mixer to
complete the reaction. The airborne exposures which can occur
are limited to copper oxide dust and ammonia fumes at the mix
tank, and ammonia fumes at the treating cylinder primarily when
the door is opened for unloading. The latter is significant
because the process is heated.

In summation, occupational exposures by the inhalation route have
occurred when CCA preservative solutions were made in the treat-
ment plants before it became commercially supplied as water
concentrates.

In contrast, ACA blending could result in exposure from two of
the three components in the material. There is a probability
of exposure through skin contact, either in handling and
transferring the water-borne solutions or when working on
leaking pumps or equipment. More typically, it can occur when
handling wet treated wood if impervious gloves are not utilized.

Biological effects observed industrially from the arsenical
materials are limited to the blending of trivalent arsenic
(NIOSH, 1975; Bingham, 1978). Documented cases of human
experiences with the mixed treatment chemicals include episodes
of poisoning in children, reportedly occurring from arsenic
wood preservatives (Johnson, 1978). In these instances, the
episodes resulted in either acute symptomology or mortality.

A recent study was conducted to evaluate occupational exposure

to CCA and ACA wood preservatives and to correlate environmental
concentrations with evidence of arsenic poisoning (Rosenberg et
al, 1980). Workers handling these arsenical compounds demonstrated
an increase in urine arsenic levels when compared to a control
group of woodworking employees not exposed to arsenic. However,
no significant differences in the physical assessment for acute
arsenic toxicity were observed between the exposed and non-exposed
groups. The authors point out that a follow-up investigation is
essential for the complete assessment of chronic or delayed
health effects, including cancer.

Individuals exposed to the arsenicals by skin contact can

develop dermatitis and folliculitis (NIOSH, 1975). Generally,
human occupational experience with the arsenical compounds

indicate a cancer risk for either the respiratory system or

skin, depending upon the mode of occupational exposure. The
trivalent material is said to result in the greatest health risk
(Bingham, 1978; Johnson, 1978). Both the trivalent and pentavalent
forms used in wood treatment are mutagenic.

21


DISCLAIMER

Mention of company names or products in this report does not constitute endorse—
ment by the National Institute for Occupational Safety and Health.

NIOSH Project Officer: James L. Oser
Principal Investigator: Alan S. Todd

DHHS (NIOSH) Publication No. 83-106

di


Area air sampling was conducted at downwind locations where
other employees were working; i.e., framing area and control
room. It was also done side-by-side with bubblers and silica
gel tubes to compare these monitoring procedures for PCP. An
area sample was taken in an enclosed PCP block storage area to
determine if airborne PCP, subliming from the 2000 number blocks,
could be detected.

Wipe/touch samples were taken on ACA and CCA freshly treated
and dry wood stacks. Dry wood was wipe sampled over an area of
approximately 10 inches square. Wet wood surface salts were
done by placing the filter on the damp wood surface over
approximately the same surface area to simulate the transfer to
the skin when handled. Short-term peak exposures to ammonia

by detector tubes were sampled next to the treater operator's
face on about five minute intervals during cylinder opening,
unloading ,and refilling.

AIR MONITORING RESULTS

The personal and area monitoring data for the pressure and
non-pressure treatment facilities surveyed during this phase of
the study are summarized in the subsequent tables for review
and discussion purposes. Wipe/touch sampling data are also
included.

64


Creosote Pressure Treatment Facilities
General Area Samples

Table 19.

Sample Description

Air Concentrations (mg/m°)
NIOSH Gravimetric UV_Absorbance

Sampling

Treatment Plant Time (Min.)

Treatment Building
Control Room

<0.001
<0.001

KK 356 <0.007
258 0.163

75


Creosote Producers in the United States, 1972 -- (continued)

Koppers Company, Inc.

Cicero (Chicago) Illinois
Follansbee, West Virginia
Fontana, California

Houston, Texas

Portland, Oregon

Kearny (Seaboard) New Jersey
St. Paul, Minnesota
Swedeland, Pennsylvania
Woodward, Alabama
Youngstown, Ohio

Reilly Tar and Chemical Corporation
Cleveland, Ohio
Granite City, Illinois
Ironton, (Provo) Utah
Lone Star, Texas
Chattanooga, Tennessee
USS Chemicals
Clairton, Pennsylvania
Fairfield, Alabama
Gary, Indiana

The Western Tar Products Corporation

Memphis, Tennessee
Terre Haute, Indiana

Witco Chemical Corporation
Point Comfort, Texas

CREOSOTE USE

The quantities and types of wood products treated with creosote

solutions from the AWPA, Wood Preservation Statistics,
as follows:

Poles 1,129,000 number
Crossties 32,862,000 number
Lumber and Timbers 113,048,000 board feet
Fence posts 6,568,000 number
Pilings 18,422,000 linear feet
Switchties 76,757,000 board feet
Crossarms 93,000 number

ll

1979 are


Table 18. Creosote Pressure Treatment Facilities
Employee Exposure Levels

Job Treatment Task Sampling Time Air Concentrations Cug/m *)
Classification Plant Evaluated (Min.) NIOSH Gravimetric UV Absorbance
Treater JJ General Treatment
Operator Operations 371 0.057 0.002

478 0.022 0.006
475 0.007 0.006
389 0.016 0.002
MM Cylinder 22 <0.110 0.120
Unloading 57 0.227 <0.002
KK Cylinder
Unloading 66 1.343 0.112
Treater Cylinder
Helper KK Unloading 55 <0.049 0.083

Locomotive Crew

o Foreman JI Cylinder Unloading 181 0.029 0.008
& Transfer Tasks 233 0.013 0.847

22 1.668 0.056

o Engineer JJ Cylinder Unloading 184 0.016 0.003
& Transfer Tasks 2133) 0.013 0.029

36 0.159 0.032

o Switchman MM Cylinder Unloading 25 0.35 0.013
& Transfer Tasks 57 0.045 0.019

o Switchman Ja Cylinder Unloading 185 0.017 0.031
Helper & Transfer Tasks 37 0.788 0.053
233 0.083 0.762

Continued

70


Surveys of manufacturers of the individual components of
arsenical preservatives -- copper, chrome, arsenic, ammonia --
were not recommended since they have been extensively studied

as part of other research for technical reports or NIOSH criteria
documents. Studies of fluoride, dinitrophenol, bis (tributyltin
oxide),nickel ethyl hexanoate, and zine chloride production
operations were not done because of their limited use in wood
treatment.

Various mixtures of arsenical preservatives are being produced
and sold under registered trade names. One facility which
manufactures copper chrome arsenate (CCA Type C) -- the most
common waterborne treatment chemical in use -- was included in
the preliminary survey phase of the study.

FIELD SURVEYS AND PRELIMINARY STUDY ANALYSIS
One-day preliminary surveys were conducted at eleven treatment
plants and two preservative manufacturing operations by a

team of investigators. The purpose of these site visits was to:

e provide familiarization with techniques used during
various treatment or other processes

e identify potential sources of exposures

e review current and past safety and health experience
with process methods and chemicals

e observe and evaluate work practices used in handling
chemicals

e evaluate the use of protective gear for routine and
emergency use

e investigate engineering or other controls used to
minimize exposures

e conduct range~finding area sampling to determine
potential levels of exposure

e field evaluate test sampling and analytical procedures
to be used for air monitoring of preservative chemicals

28


Additional experiments with spiked samples prepared and analyzed
within the laboratory indicated similar non-linearity and lack
of reproducible data.

Alternate Analytical Procedures -- Since high molecular weight
hydrocarbon mixtures absorb in the UV spectrum, a follow-up
analysis of this type was suggested on aliquots of the cyclo-
hexane extracts remaining from spiked samples. This was done to
determine if it might provide a better quantitative index of
extractable creosote than the NIOSH gravimetric procedure.
Standard solutions containing 2, 20, and 200 micrograms of
creosote per milliliter of cyclohexane were first prepared by
the laboratory. Using a UV scanning instrument, an absorption
spectrum was determined for different bulk creosote samples on
hand. At 252 nm all samples absorbed maximally and absorbance
versus concentration were linear across the range of standards.
Additional sets of spiked samples were also prepared and
analyzed by both the gravimetric and UV methods for further

comparative purposes. The results are as follows:
ug Creosote/Filter Analytical Results
Spiked Quantity Gravimetric UV_Absorption
20 35 13.5
20 30 9
50 15 27
50 20 27
100 5) 56.5
100 25 60
200 70 134
200 45 126
Blank Filter 10 te)
Blank Filter 5 (7)
100ug in 5 ml cyclohexane 40 91.5

The results from gravimetric analysis show none are significant.
The UV absorption data appears linear but recovery is not
complete and averages 50-65% at the lower concentrations added.
Benzene appeared to be a slightly more effective extraction
solvent than cyclohexane. The difference is not significant

as shown in Table 5. The UV data appears reproducible but
consistently does not give complete recovery of creosote added.
The method also requires standardization with the reference
creosote solution in use at each plant, since compositions and
UV absorbance vary considerably. We assume that part of the
reason for incomplete recovery is due to the polar and non-polar
hydrocarbon compounds present in creosote.

35


SUMMARY OF DATA AND CRITERIA
FOR THE COMPREHENSIVE SURVEY PHASE

SUMMARY OF DATA

The preliminary area monitoring conducted at the PCP
manufacturing facility showed non-detectable levels of airborne
PCP. Air concentrations of CCA in that plant represent abnormal
exposure conditions due to materials transfer problems. Due to
the small number of employees at these few plants throughout

the United States and the sophistication of their medical,
industrial hygiene, and safety programs, follow-up comprehensive
surveys were not recommended for Phase III.

The preliminary survey data on the treatment plants suggested the
following:

e Maximum peak air concentrations of PCP at critical
emission sources in pressure treatment facilities should
be at or below the TLV. Based on the time spent at or
near emission sources eight hour average employee
exposures would probably be well below the current
occupational limit of 0.50 mg/m*® based on the data.

e Airborne levels of PCP monitored at non-pressure
treatment plants varied from 0.13 to 1.33 mg/m?
indicating a potential for brief but significant peak
exposures for treatment plant or assisting personnel at
locations adjacent to the treatment tank or vessel.

e Cyclohexane extractable hydrocarbons in air samples
taken at creosote treatment (pressure and non-pressure)
plants varied from 0.09 to 9.71 mg/m? by the UV analysis
method. The data suggest the potential for significant
exposures for very brief periods of time during cylinder
or tank unloading. Many of the gravimetric assay
results correlate with neither the UV data or sensory
indications of airborne creosote.

e Airborne trace metal in CCA and ACA treatment plants
were negligible, usually below the limits of detection,
suggesting that average inhalation exposures for plant
employees are very low or nil.

60


Ten milliliters of methanol were added to each sample before
High Performance Liquid Chromatography (HPLC) and analysis by
ultraviolet absorption at 254 nm. A standard calibration curve
for pentachlorophenol was prepared and analyzed under the

same conditions. They cover the range of 12.5 wg to 250 ug in
25 ml of ethylene glycol-methanol mixture. The lower limit of
quantitative detection by this method was 12.5 micrograms per
sample.

To determine if the chromatographic procedure was linear with
acceptable recovery, standardized samples were spiked with known
amounts of pentachlorophenol. A recovery of 120% was reported.

Dow procedure -- This method entails desorption of the silica
gel and glass wool plugs in 10 milliliters of chilled 10%
methanol in diethylether with gentle shaking for two hours.

Five milliliters of the extract is derivatized with diazomethane
and analyzed by gas chromatography using an electron capture
detector.

For the initial field surveys, the laboratory chose methylene
chloride for the desorption solvent and analyzed for
pentachlorophenol directly by gas chromatography (FID detector)
without derivatization. The minimum detectable amount of PCP
by this method was only 20 micrograms per sample. Using an
electron capture detector by derivatization from the methanol-
diethyl ether solution. followed by gas chromatography analysis,
the sensitivity was improved to 0.03 micrograms per sample.

At the request of NIOSH, a prefilter was used with the silica
gel procedure to determine if particulate PCP was airborne.
Various desorption media were used. In the first field study,
the prefilter was immersed in ethylene glycol at the completion
of sampling and analyzed by the NIOSH gas chromatographic
method. Since this utilized two analytical procedures for one
sampling method, it was considered inappropriate for the
evaluation of the Dow method and was discontinued. The

silica gel desorption solvent dissolves the 0.8 micron MCA
prefilter, thus precluding the combining of extracts. Methylene
chloride was used by the laboratory for: initial desorption and
replaced by solvent exchange with the methanol/diethyl ether
solution before derivatization and analysis by gas chroma-
tography.

31


COMPREHENSIVE SURVEY RESULTS
DESCRIPTION OF FACILITIES SURVEYED

The treatment facilities included in the comprehensive phase
of study are listed in Table 14. Process methods, products, and
preservative chemicals utilized are delineated.

SURVEY METHODS
Non-Pressure Treatment Plants

The facility exclusively utilizing a PCP non-pressure process
(Plant CC) was treating cedar utility poles in full-length and
butt tanks during the survey period. Personal monitoring was
conducted on the two treatment operators who have the greatest
exposure to airborne PCP because of their proximity to the tanks
for the greater part of the shift. One operator works the day
shift, while the other operates the plant through the evening
until the processing is well into the cold cycle. Other plant
personnel assisting in the loading and unloading of the
treatment tanks during the day shift were monitored. This
included crane operators, yard crew, and others boring freshly
treated poles for quality control assay purposes. Exposures
during tank unloading were anticipated to be highest since the
poles are hot and visible fumes, odor,and steam emissions are
evident.

Area monitoring was conducted during the treatment cycle to
determine downwind PCP exposures in occupied areas during
emission periods and compare the two sampling analytical
techniques.

Pressure Treatment Plants

Personal breathing zone air monitoring was conducted on treater
operators, the locomotive crew, forklift operators,and other
exposed yard personnel who assist or handle freshly treated
lumber. Sampling was done for creosote, pentachlorophenol, and
trace metals emissions from the ACA and CCA processes. Where
possible,a combination of short and long-term personal samples
were taken to quantify peak and average exposure levels. The
monitoring included exposure tasks such as cylinder door
opening and removal of treated wood; unloading of freshly
treated wood from tram cars; and restacking, and metal banding
of these materials for shipment or storage.

63


Table 6. (Continued)
TREATMENT wooD AGE OF WORKER
PLANT PROCESS PRESERVATIVE TREATED PRODUCTS PLANT TANK OR CYLINDER POPULATION
J Pressure Creosote/petroleum oil Railroad ties 76 years 4 8' x 155" 4 treaters
(30/70, 50/50) Bridge timbers L 6' x 132° gx
CCA, Type C Sign base material
K Pressure CCA Type C Dimensional lumber 8 years 1 - 8' x 40! 6 treaters
Non-Pressure PCP Type A bridge timbers 2 - 8' x 95" 10*
(thermal) Creosote guard rail posts 1 8' x 105"
ACA 1 20' x 20'
Dual treatment
(ACA, creosote)
L Non-Pressure Creosote Poles 55 years 1 12' x 20° 5 treaters
(thermal)

st

*others helping with loading/unloading tasks


Engineering recommendations, such as local ventilation, would
have limited value in reducing exposures in most treatment
plants, since they are out of doors. The possible exceptions
are pump room facilities. Hydraulically operated doors with or
without automatic bridge rails for the tram cars will reduce
exposure time at the cylinder opening and limit proximity. They
should be considered in long-term engineering control planning.
Positive pressure cylinder gaskets on the door rather than the
cylinder reduces the probability of damage during the loading
and removal of treated wood. We recommend them because gasket
changes, when they occur, require closer proximity to the
cylinder for longer time periods than loading and discharging
tasks. For operations using flaked PCP in bags, we recommend
local exhaust when bag dumping is done.

Pre-employment and periodic medical surveillance programs are
recommended based on potential health effects from airborne
exposure and contact with the treatment chemicals. This should
serve as a means of assuring that overexposure and health effects
are not occurring. It will also substantiate whether significant
skin contact and absorption, not quantifiable by air sampling,
occurs. The medical physical examinations should be oriented

to detect both the specific treatment chemical in biological
fluids, where possible, and evaluate the more sensitive indicator
systems for signs of early reversible health changes.

Specifically, we recommend the following be included in generally

comprehensive pre-employment and annual periodic medical
examinations by treatment chemical.

Pentachlorophenol

Urinary levels (24-hour composite)
Blood - Standard SMA-12 profile
Liver Function - SGOT and SGPT
Skin Examination and history for dermal reaction and
photosensitization.
Creosote

1. Preplacement Physical Examinations

The medical and work history questionnaire should include
questions regarding photo-sensitivity and skin irritations
or sensitivity. In addition to the regular pre-place-
ment physical examination and appropriate laboratory
tests, all skin areas should be thoroughly examined.

83


BACKGROUND
HISTORY OF WOOD PRESERVATIVE USE

Wood preservatives are chemicals or mixtures which are used to
treat wood for the prevention of decay and deterioration which
occurs as a result of weather, soil conditions, or the infectation
by organisms such as insects, fungi, and marine borers. Several
treatment chemicals and processes have been developed over the
past 150 years, some of which are still in use today.

In the early 19th century, inorganic salts such as mercuric
chloride, copper sulfate, and zinc chloride were used for pro-
tection against decay. Treatment was done by immersing the wood
in a solution of the metal salts. Mercuric chloride was used in
the first treatment plant built in the United States (Hunt and
Garrett, 1967).

Coal tar creosote came into use in 1839 with the Bethell full cell
pressure treatment process. The lumber or posts are enclosed in
a cylinder and subjected to an initial vacuum to remove air and
water from the wood cells, followed by injecting creosote into
the wood under pressures varying from 125-200 pounds per square
inch (PSI) at temperatures of 180-210°F. Treatment continues
until the wood is saturated with creosote. Pressure is then
released, the cylinder drained, and the door unbolted manually
or automatically by hydraulics to permit wood removal. A short
final vacuum is often utilized to remove excess creosote from
the surface of the wood. This treatment method retains the
maximum quantity of preservative in the wood cells (Hunt and
Garrett, 1967).

The Bethell Process proved to be the most expensive treatment
method available in the middle of the last century and, as a
result, creosote use was not common. Its use was limited almost
exclusively to marine piling applications, since it was the
only preservative to provide effective protection.

Zine chloride was initially used by the railroad industry in the
1800's for pressure treatment of crossties. Later a zinc chloride/
creosote mixture was used which was as effective as the creosote
treatment, but less costly. This process continued in use into

the 1920's.


CONTENTS

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Tables . 2. 6 6 6 ee ee ew ee ew ew oo soe
Acknowledgements . .........4.-. o o
Introduction... 1... ee ew ee eee 0 0
Background... .... 2... 9000 a

History of Wood Preservative Use. .

Wood Preservatives in Current Use ........

Health Effects of Wood Preservative Chemicals and

BOlmMEH@ME o 5600000 co oo ob oo ooo
Methods of Survey ......... + es eee 9

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Identification and Selection of Facilities for Study.25

Field Surveys and Preliminary Study Analysis . .

Description of Preliminary Plant Surveys ......
Wood Treatment Facilities ....... 06 Oo
Production Facilities . . 1... . 1... eee

Results of Preliminary Surveys ....

Manufacturing Operations ...........
Wood Treating Operations ...... see
Summary of Data and Criteria for the Comprehensive
Survey Phase... .. . eee ee ee ee ee
Summary of Data... . 1 1 1 ee ee ee ee
Criteria for the Comprehensive Survey Phase...
Comprehensive Survey Results ...........4.
Description of Facilities Surveyed .......
Survey Methods . ...... 2. 2. 2. ee ee eee
Air Monitoring Results .........4.4.+248+48
Analysis of Results ..... 6.6... eee eee
Overall Study Analysis .......... 2...
Recommendations ~~... 2 2 e+ ee ee ee we ee ee
References . . 1 2 6 ee ee ee we we we te ew

28
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+38

42
42
45

. 60

-60
-61

+63
+ 63
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64
66
78
- 82

-87


DESCRIPTION OF PRELIMINARY PLANT SURVEYS

WOOD TREATMENT FACILITIES

The treatment facilities included in the preliminary phase of

the study are described by process methods, products,

preservative chemicals in use, worker population, etc. in

Table 6. The facilities are coded to preserve their anonymity.
They were selected to reflect geographical distribution of

plants, processes currently in use, and small and large operations.
Specific efforts were made to include older type processes now

in limited use to depict past practices and exposure risk.

PRODUCTION FACILITIES
Manufacturer of Pentachlorophenol

In the facility surveyed, pentachlorophenol (PCP) is produced by
the chlorination of phenol in the presence of a catalyst at
elevated temperatures. The plant has been in operation for
twenty-three years. The raw materials -- phenol and chlorine
gas -- are pumped into a primary reactor vessel where partial
chlorination occurs. The intermediates are transferred to a
secondary reactor where the chlorination process is catalytically
completed. The molten product is crystallized on a water-cooled
rotating drum and polished flakes are formed in the final
temperature-regulated processing cycle. The PCP is shipped

from the plant predominantly by tank truck, with a limited
amount packaged in bags, drums, and boxes. There are ten
employees in the pentachlorophenol production operation.

Manufacturer of Chromated Copper Arsenate

Chromated Copper Arsenate (Type C) is mixed and produced in a
batch-type reaction system. The facility surveyed has been in
operation for only three years. No other operations or processes
are conducted on the plant premises. Drums of chromic acid
(crystalline) and copper oxide are added to an arsenic acid
solution in the reactor. The solution is agitated in order to
optimize chemical reaction conditions. When quality control
parameters indicate the reaction is completed, the product is
pumped to storage tanks for assay and shipment as needed by
truck. All the production tasks are conducted by two operators.

38


Table 17.

PCP Non-Pressure Treatment Facility (Plant CC)

General Area Air Monitoring

Air Concentration (yg/m*)

Sample Description Sampling Time (Min.) Dow Method
Downwind full-length

Treatment Tank

Distance 90 Feet 237 3.8

115 Feet 72 2.3

Downwind butt dip

Treatment Tank

Distance 15 Feet 128 7.9
Treatment Building

Control Panel 123 37.8

Operator's Desk 78 44.5
Cab of Crane - Unloading

Full Length

Treatment Tank 96 8.0

69


OVERALL STUDY ANALYSIS

With few exceptions, employee exposures to preservative chemicals
during wood treatment are well below the current occupational
standards applicable for these compounds. Short-term peak
exposures occurring during critical tasks such as cylinder
opening and unloading, when filling non-pressure tanks with hot
PCP oil solution, and during inspection of treated wood inside
the non-pressure treatment tank were also typically well below
regulatory limits. Air concentrations in occupied areas adjacent
to treating and downwind were lower,indicating lesser exposure
risk to yard crew and other non-treating personnel. Airborne
concentrations of trace metals from the ACA and CCA processes
were typically below the limits of analytical detection.

Multiple exposures in plants using more than one treatment
chemical do not appear to result in excessive health risk even
where several mediums are in use simultaneously during any work
shift. The data represents typical exposure levels expected in
large plants using current basic commercial treatment processes.

The personal sampling data generated is in general agreement with
past surveys conducted by the wood treatment industry and Health
Hazard Evaluations done by NIOSH.

A number of the plants surveyed during both field study phases
have done extensive engineering renovations and process changes
in recent years. These have been primarily oriented to
production efficiency and improvement of process methods rather
than control of exposures per se. They have in many instances
resulted in lower airborne exposures because of the reduced time
requirements for critical tasks or the ability to perform some
operations where significant exposure can occur from more

remote locations. Examples of these include installation of
automatic hydraulically operated cylinder doors and rails,
improved methods of switching tram cars for changing and unloading
the pressure cylinders, and custom mechanized equipment for
loading and unloading thermal tanks.

In addition, the availability of commercial preblended pre-
servative formulations or automated closed system blending
techniques have dramatically altered potential exposure levels
to these materials during the preparation of the treating
solutions. This is particularly important for the PCP and
waterborne arsenical compounds.

Only limited experience and data are available from site visits

to the manufacturing facilities. Generally, however, they are
much more sophisticated in terms of control procedures because of

78:


INDUSTRIAL HYGIENE SURVEYS OF OCCUPATIONAL

EXPOSURE TO WOOD PRESERVATIVE CHEMICALS

Alan S. Todd, M.S.
Cynthia Y. Timbie, M.S.
Stewart-Todd Associates, Inc.
Wayne, Pennsylvania 19087

Contract No. 210-78-0060

U. S. DEPARTMENT OF HEALTH AND HUMAN SERVICES
Public Health Service
Centers for Disease Control
National Institute for Occupational Safety and Health
Division of Surveillance, Hazard Evaluations and Field Studies
Cincinnati, Ohio 45226

February 1983

For sale by the Superintendent of Documents, U.S, Government
Printing Office, Washington, D.C. 20402


ABSTRACT

Industrial hygiene studies were conducted at eleven wood treating
plants and two manufacturing operations as part of an industry-
wide evaluation of worker exposure to wood preservative chemicals.
The purpose of these field studies was to evaluate airborne
exposure levels and characterize existing work practices and other
methods of exposure control.

The wood preservative industry is comprised of over 1,000 plants
in the United States with the majority employing less than ten
workers in wood treatment processing. Approximately 500 plants
are members of industrial trade associations: American Wood
Preservers Institute (AWPI) and American Wood-Preservers'
Association (AWPA), and others. It is estimated that about ten
major plants produce 50% of the total treated wood in the United
States.

The report presents the findings from preliminary walk-through
and in-depth industrial hygiene studies of the various wood
preservative processes.

In general, employee exposures to preservative chemicals during
wood treatment were well below the current applicable occupational
standards. Short-term peak exposures occur during critical tasks,
such as cylinder opening and unloading, when filling non-pressure
tanks with hot PCP oil solutions, and during inspection and
sampling of treated wood. The exposure levels measured were all
well below current guidelines for significant health risk.

The personal sampling data generated from the comprehensive study
is basically in agreement with exposure findings of past surveys
conducted by the wood treatment industry and Health Hazard
Evaluations done by NIOSH.

The study emphasizes the need for improved work practices to
further minimize worker exposure and contact with recognized toxic
chemicals during emergency spills, non-routine situations or
critical process tasks. Recommendations are given for personal
protective equipment, modified work practices, and medical
surveillance programs.

This report was submitted in fulfillment of Contract No. 210-78-0060

by Stewart-Todd Associates under the sponsorship of the National
Institute for Occupational Safety and Health.

iv


They are grouped by treatment process and georgraphical location
in Table 4.

Table 4. Treatment Facilities Contacted

Geographical Pressure Non-pressure Pressure &
Location Treatment Treatment Non-pressure
West & Northwest 7 6 2
Central 5) 4 1

South & Southeastern 17 2
Northeast 2 1

Note: No information was available for 9 of 56 initial contacts.

Eleven plants were chosen for preliminary surveys. Seven were
pressure treaters who utilized some or all of the three major
preservative chemicals. A few indicated limited use of the minor
wood treatment chemicals such as Cu8-Quinolinolate and TBTO.

Two had non-pressure (thermal) treatment with pentachlorophenol
and one with creosote. A vacuum process using pentachlorophenol
was also included.

Non-pressure treatment processes in recent years have been
diminishing in number either because of process changes or plants
closing. Only one thermal creosote system in routine use was
identified during the initial plant review. This plant butt
treats Douglas Fir, western pine, and ¢edar utility poles for use
in low rainfall areas of the country where full-length treatment
is not needed. Facilities using pentachlorophenol by the non-
pressure thermal process were more numerous. They are concentrated
in the Northwest and North Central regions of the United States
where cedar and Douglas Fir are available. The vacuum process
was identified only at small, so-called "Ma and Pa" operations
in the south central states. The latter treatment processes

were included in the study since they represent systems which,

in the past,were in more widespread use. Monitored exposure
levels would provide indications of the relative health risk when
compared with more automated and mechanized processes. Plants
which do hand application by brush, paste,or simple dipping
operations. could not be found anywhere in the United States.

Pressure systems predominate for commercial treatment of wood.
They provide a deeper, more uniform preservative retention,
shorter treatment cycle, and,in some processes,the wood can be
preconditioned in the cylinder. Equipment costs are much greater
than for non-pressure systems and,therefore, pressure treatment
is used primarily for larger sustained production operations
(Fuller et al, 1977).

26


We also recommend that either the wood preservatives industry
or EPA consider computerizing medical data for retrospective
determination of acute and long-term health effects. This
compiled data would be useful in answering questions regarding

the carcinogenicity and teratogenicity of the treatment materials
now used.

PROTECTIVE CLOTHING

When doing short-term cylinder entry tasks, disposable coveralls
or others which can be laundered should be utilized. Impervious
gear could be used but might result in excess heat burden except
during periodic cylinder shutdown, cleanup,and maintenance.
Observations made during the on-site surveys indicate there is
also some clothing contact with the treatment chemicals by yard
personnel involved doing loading and restacking of freshly treated
wood. Coveralls should be provided and laundered commercially

to avoid taking the material home resulting in household
contamination. There should be a required change of work clothes
when they show obvious signs of contamination and on a scheduled
basis. Only street clothes should be worn to and from the plant.
Adequate work-street clothing change facilities are needed at

many of the plants to meet current guidelines. Gloves should be
selected for impermeability and acceptability for the specific
wood treating chemical. There is a need for research to determine
the best glove material and type for employee protection without
encumbering the workers; i. e., hot environment.

SHOWER, WASH AND BREAK FACILITIES

Shower and wash-up facilities are needed adjacent to eating and
locker change areas. Some plants already have suitable facilities,
while in others these are minimal or non-existent. Some plants
have pressurized or air-conditioned control rooms for breaks and
lunch. They are satisfactory for these purposes if good wash-up
facilities are immediately adjacent. These must be well cleaned
and maintained free of contaminants. We recommend positive
pressure control rooms for those facilities where operators must
eat while on duty.

ENGINEERING CONTROLS

Engineering recommendations, such as local ventilation ,would have
limited value in reducing exposures in most treatment plants,
since they are out-of-doors. The possible exceptions are pump
room facilities. Hydraulically operated doors with or without
automatic bridge rails for the tram cars will reduce exposure
time at the cylinder opening and limit proximity. They should be
considered in long-term engineering control planning. Positive
pressure cylinder gaskets should be on the door rather than the
cylinder. This reduces the probability of damage during the
loading and removal of treated wood. Also, gasket changes
require closer proximity to the cylinder for longer time periods
than loading and discharging tasks. Local exhaust during bag
dumping is recommended for operations using flaked PCP in bags.

85


Of most concern is the handling of freshly treated or wet wood
which is not hot since gloves of necessity are worn when direct
contact is expected. In some instances, the cloth gloves
appeared significantly soaked from surface contact with the
treated wood and skin staining was observed. This tends to be
more common with the salt treated wood because dermatitis

or acute photosensitization reactions do not occur. Work
practice training and evaluation at treatment plants are highly
variable. Some of the larger facilities have safety and health
programs with on-site visits by professional corporate staff
personnel or insurance carriers. These have resulted in
modification of work practice procedures, in addition to some
engineering modifications which have reduced the potential for
exposure either by inhalation or skin contact. At other
facilities, the general level of safety awareness is more
typically aligned to the general saw mill wood processing
industry. Most have a general cognizance of the need for safety
and equipment guarding, etc., but no significant orientation to
the basic chemical or other health aspects of the treating
process or materials.

The greatest source of exposure resulting from poor work practices
is skin protection and contaminated street clothes when handling
freshly treated wood during emergency situations where cylinder
entry is necessary, or the cleanup of spills and repairing
leaking pumps, etc. At least two incidences were noted during
the site surveys where respiratory and other personal protection
should have been utilized. In a few plants, eating and coffee
breaks are taken in treatment areas. This practice in
contaminated areas adds another source of exposure through food
and drink contamination. Some small plants lack sanitary
facilities immediately adjacent to break areas which discourage
cleanup of hands to minimize possible incidental ingestion and
skin absorption.

Employee training and education at most plants reflects the
general wood processing industry, with emphasis on safety, back
injuries, control,and first aid treatment of splinters. Many of
the treater operators and assisting personnel are unaware of the
potential health effects of exposure to the chemical used and
appropriate work practices and other methods needed to minimize
exposure both airborne and contact to preclude acute or long-term
health effects. In some instances,the plant managements do not
have a thorough practical understanding of possible adverse health
effects and control needed. Some of the larger companies are
beginning to assemble training and education programs for
supervisors, treater operators, and other personnel who work

with treated wood. However, to date, most have not been
implemented.

A few of the plants have initiated medical surveillance programs
since 1978. None, however, have medical programs of significant
time history. Many of the plants, particularly the smaller ones,
have no medical surveillance. Some do not even conduct

80


Hot oil (210-220°F) solution containing the preservative is pumped
into the tank to cover the wood for six to eight hours. The outer
sap wood cells release air under these conditions. When the hot
oil is replaced with cooler (150°F) solution, a partial vacuum

is produced and preservative oil penetrates the wood (Hunt and
Garrett, 1967).

OTHER HISTORIC PROCESSES

The diffusion processes depend on the gradual migration of water
soluble preservatives from a concentrated source into the bound
water already in the wood cells. Green or freshly cut wood is
covered with a concentrated strength preservative in a cream or
paste form. The wood is then tightly covered with waterproof
paper or other suitable vapor barrier and allowed to sit for
thirty days (Hunt and Garrett, 1967).

Double diffusion processes involve the consecutive application,

by either dipping or spraying, of two chemicals which will react
within the wood to form a leach-resistant biocidal precipitate.

While these methods have been shown to produce excellent leach-

resistant products, they are no longer in commercial use (Fuller
et al, 1977).

The vacuum treatment method is used to a limited extent
commercially for the application of PCP preservative to millwork
and exterior lumber. The lumber being treated is placed in a
sealed container which does not necessarily have to be cylindrical.
A partial vacuum is used to remove moisture from the wood, and the
preservative solution is added until the uptake by the wood ceases.
The vacuum is released and the container opened manually. The
method requires much less expensive equipment than pressure
methods and is,therefore, more likely to be found only at small
operations, such as local lumber and millwork vendors (Hunt and
Garrett, 1967).

WOOD PRESERVATIVES IN CURRENT USE
Wood treatment chemicals are classified into four subgroups:

1. Creosote or mixtures of creosote with petroleum oils or
coal tar.

2.  Pentachlorophenol (penta) solutions in light to heavy oils,
or volatile solvents.

3. Waterborne preservatives.
4. And others.

The most recent estimated use of major chemicals is provided by
the USDA EPA Preservative Chemicals RPAR Assessment Team (1981).


Air Sampling Results - Preliminary Surveys --

Area samples were taken at locations where maximum air
concentrations of preservative chemicals were anticipated to
maximize the amount of material collected and permit a comparison
of sampling and analytical procedures. It would also permit an
estimate of potential short-term peak exposure levels to
treating operators or others in assisting yard crew. Examples
of the sampling sites were: adjacent to the cylinder door during
the removal of treated wood products; on tram cars of freshly
treated wood; in treatment buildings adjacent to pumps or
valving used to transfer hot preservative solutions; and down-
wind of heated tanks, etc. The results of the monitoring are
summarized by location and treatment chemicals in the following
tables:

Table 7. Airborne Concentrations of Pentachlorophenol (PCP)
Current TLV 0.5 mg/m®

Air Concentrations (mg/m°)

Treatment NIOSH Dow Cranmer & Frael
Sample Location Plant 8-297 Silica gel NaOH Bubblers
Treatment Bldg. A <0.03 <0.0003

adjacent to pumps
and valving

Adjacent or above A 0.51 0.20
cylinder door when
opening or re- F 0.04+ 0.01
charging
K <0.22 0.39
On top of freshly A 0.25 <0.26%
treated wood
F 0.12+ 0.11
K <0.02 0.05

tprefilter analyzed by Dow Method
*prefilter analyzed by NIOSH Method

50


REFERENCES

USITC, 1977. United States International Trade Commission.
Synthetic Organic Chemicals, U.S. Production and Sales,
Publication No. 920. Washington, D.C.

Whitaker, P.H., 1945. Radiological appearances of the chest
following partial asphyxiation by a smoke screen. Brit. J.
Radiol. 18 (216): 396-397.

Wolf, A.F., 1975. Occupational diseases of the lungs: III
Pulmonary disease due to inhalation of toxic gases, aerosols
and fumes. Ann Allergy 34(3): 165-171.

Wolfe, R.R., R.-H. Adams, and D.T. Desilets. 1967. Pneumatocoeles
complicating hydrocarbon pneumonitis. J. Pediatr. 71: 711-714.

Wyllie, J.A., J. Gabica, W.W. Benson, and J. Yoder, 1975.
Exposure and Contamination of the Air and Employees of a
Pentachlorophenol Plant, Idaho - 1972. Pestic. Monit. J. 9(3):
150-153.

92 ‘US GOVERNMENT PRNTINGOFRCE 10m - 659-096/626


Page Two of Table 18

Job Treatment Task Sampling Time Air Concentrations (ug/m*)
Classification Plant Evaluated (Min. ) NIOSH Gravimetric UV Absorbance
Yard Crew KK Unloading Tram 280 0.159 0.008

Cars 230 <0.013 <0.001
250 <0.010 <0.001
247 <0.010 <0.001
Pettybone JI Unloading Tram 303 0.010 0.004
Operator Cars
Checker &
Forklift JJ Unloading Tram 301 0.010 1.211
Operator Cars 360 0.020 0.016
Tie Lining Unloading

Operator IJ Tram Cars 298 0.060 0.016

71


Laboratory Comparison of Analytical Methods for PCP -~ Initially
conflicting field data from the two analytical methods indicated
the need to determine the sensitivities and reproducibility of
the two PCP sampling and analytical methods under controlled
conditions. Randomly numbered spiked samples were prepared

and sent to the laboratory for analysis. The results of those
analysis were as follows:

Sample No. Quantity Spiked (yg) Quantity Assayed (jg)

(Silica gel tube) DOW Method
1 1.0 85
2 Blank <.50
3 1.0 65
4 0.2 <.50
5 Blank <.50
6 5.0 70
7 5.0 60
8 0.2 <.50

(Filter) NIOSH Method
A 9.0 62.5
B 4.5 37.5
Cc 18.0 130.0

(Ethylene Glycol/Methanol)

D 4.5 47.5
E 9.0 95.0
F 18.0 190.0

The data showed no correlation between the quantity added to the
filter or tube and the amount determined. In addition, the
lower sensitivity for reasons not explained by the laboratory
shifted from the previous 0.03 micrograms lower sensitivity

to 0.5 micrograms by the Dow method. The fiberglass plugs

in the silica gel tubes were also excluded from the extraction
step by the laboratory contrary to the outlined procedure.

The results of the NIOSH method were consistantly in error by

a factor of approximately tenfold. As a result of the problems
incurred with the pentachlorophenol analysis methods in both
the preliminary field and laboratory prepared samples, another
AIHA certified laboratory was contracted for the remainder of
the survey work.

Additional sets of spiked samples were prepared for the NIOSH
and Dow methods. These were submitted for analysis by the
NIOSH S-297 and Dow methods. A minor modification to the Dow
procedure was utilized as requested by the laboratory. In
place of Diazomethane recommended in the EPA method for PCP
in water, N-ethyl-N'-nitro-N-nitrosoquanidine was used to

32


Analysis of Data--

The samples were taken at locations which represent peak
exposure sources. Either the peak concentration was of too
short a duration for analytical detection or the natural
ventilation throughout the unit diluted any airborne PCP to
below the limits of detection because it was a windy day. Short
peak exposures do occur, as evidenced by the seal leak which
happened just after the area sampling was completed.

Chromated Copper Arsenate --

Only one CCA manufacturing plant was surveyed in the preliminary
phase of the study. Therefore, we have no basis for comparison
of process methods, controls, work/practices, etc. with other
facilities. This is emphasized because the plant is new and is
totally isolated from other company facilities.

Engineering Controls--

The reactor is equipped with exhaust ventilation to a scrubber.
It was designed to minimize airborne exposures when raw
materials are added directly to the reactor opening. An
automated material handling system for drums was installed to
reduce potential chemical exposure, increase productivity,

and improve material handling. This is also equipped with
local exhaust ventilation to the scrubber. The effluent from
the scrubber is recycled as process dilution water for CCA
production. Empty raw material drums are passed through an
automatic washer and the rinse solution is also recycled as
process water for the reactor. The washer was installed for
the purpose of minimizing skin contact from these raw materials.
Periodic plugging of the automatic feed system does occur, and
if not readily correctable,dry materials are manually dumped

at the reactor opening.

Protective Equipment and Work Practices --

Work uniforms, hardhats, and safety shoes use are required for
operators. During all material handling tasks, goggles, gloves,
and chemical cartridge respirators are also mandatory. Employees
are also required to shower and change to street clothing at

the end of the shift. .Excellent facilities are provided for

this purpose in the dual locker change room. The routine use

of arsenic acid solution, instead of dry arsenic salts,

minimizes airborne exposure levels, since the acid solution is
pumped to the reactor vessel through a closed system.

Medical, Industrial Hygiene and Safety Programs --
Pre-employment and periodic physical examinations are required
for the operators of the CCA plant. Medical evaluations include

chest x-ray, pulmonary function, urinalysis, blood assays,
hearing and vision tests.

44


in only one of seven pressure treating plants surveyed. A full-
face canister respirator was used only during cylinder unloading
of ACA treated wood. It was required because of ammonia fumes
which were irritating to the plant treating personnel. Treatment
plants purchasing drums of CCA concentrate require operators to
wear face shields, gloves, and impervious aprons when handling
and preparing the material for dilution. Half-face dual
cartridge respirators were provided for mixing ACA and
disposable nuisance dust respirators when bag dumping copper
oxide. Most plants had emergency shower and eye wash facilities
centrally located near the treating cylinders and tanks.

Approximately half of the pressure treating facilities surveyed
during the preliminary phase provide work uniforms for the
treating operators; the uniforms are laundered by a commercial

service. For the remainder of the plants, employees bring work
clothing from home and provide their own laundering of street
clothes or coveralls. Shower and change facilities were

available at all plants except one. Their use, generally
optional, is limited. Treatment plant operators generally take
their lunch break in the control rooms, since it is a continuous
process requiring supervision and control.

Medical, Industrial Hygiene, and Safety Programs --

All plants, with the exception of two plants (A and G), require
pre-employment physical examinations for new employees. These
are general routine examinations conducted primarily to screen
for specific problems, such as back injuries etc., which would
limit an individual's capability to perform some demanding
physical tasks in the plant. Periodic medical examinations are
provided for treatment plant operators only at one facility
(plant J). It is done on a voluntary basis, but most employees
participate in the program. Medical tasks include pulmonary
function, blood assays, x-rays, and general personal medical
evaluation.

Physical examinations and other routine or emergency medical
treatment are handled by local physicians in nearby communities.
In many plants, there are one or more employees trained in
first aid treatment and CPR procedures.

Plant managers generally are responsible for safety programs
since most treating facilities have work populations of 100 or
less employees. Depending on the size of the plant, formal or
informal safety meetings are held periodically to discuss
questions or problems relating to safety. Employee process
orientation and informal safety training are also conducted by
supervisors.

Previous industrial hygiene monitoring had been done at two of

the seven pressure plants surveyed (F and H). It was conducted
as part of the corporate industrial hygiene program.

49


Biological levels of arsenic are also done periodically.
Personal air monitoring is conducted in addition to exhaust
ventilation equipment evaluation on a periodic basis.
Questions or problems relating to safety are handled by the
plant manager.

Air Sampling Results --

Area air sampling was done at locations where the greatest
source of potential employee exposure could occur. ‘Two
sampling methods for chromium were utilized. Samples were
taken side-by-side to evaluate and compare the procedures.

The automated material handling system malfunctioned due to
raw material plugging during the survey period. The remaining
materials had to be manually dumped into the reactor and

the air sampling reflect this change in tasks. The results are
summarized as follows:

SAMPLING LOCATION

DESCRIPTION COMPONENT CONCENTRATION
Top of reactor, copper 0.135 mg/m?
adjacent to lid arsenic 0.024 mg/m?
opening total chromium 0.022 mg/m?
hexavalent chromium 0.015 mg/m?
Adjacent to material copper 0.019 mg/m?
transfer station arsenic 0.004 mg/m?
total chromium 0.004 mg/m°
hexavalent chromium 0.001 mg/m?

Analysis of Data --

All airborne levels of compounds of concern were significantly
higher at the top of the reactor than at the transfer station,
This sample was taken adjacent to the reactor lid opening and
dves not represent the employee's actual breathing zone concentration
because of the close’ proximity. In addition,the employee was
utilizing respiratory protection and,therefore, his exposure
should have been negligible. A comparison of the two sampling
and analytical procedures for chromium indicates that slightly
lower levels are obtained with the hexavalent method.

WOOD TREATING OPERATIONS
Pressure Treating Plants and Processes
Description of Industry and Common Factors --

The preparation of the wood prior to treatment may or may not be
conducted as part of treatment plant operations. Many facilities

45


In most creosote and PCP plants, only the treatment operators
and locomotive crew and/or forklift operators, where they are
utilized, are the most significantly exposed. The yard crew
who assist in loading and unloading of tram cars typically have
lesser airborne exposures. However, they do have a significant
probability of skin contact, particularly if the wood is sorted
and stacked when it is wet or treated the same day.

Exposure levels for all personnel are influenced to some extent
by direction and velocity in addition to ambient weather
conditions. TWA exposures over the full shift are expected to
be well below the short-term measurements taken during the
critical process tasks.

Grab samples for ammonia during ACA cylinder door openings

showed airborne levels of up to 250 ppm (Plant KK). The
operators wear a canister respirator approved for ammonia fumes
and, therefore, should not have had any measurable exposure.
Another sample taken two feet downwind of the treated material,
after its removal from the cylinder, also showed 250 ppm. No one
however, was working at that location. The yard crew responsible
for unloading the tram cars may occasionally be exposed to
excessive levels of ammonia for short periods of time depending
on the interval between cylinder discharge and tram car unloading.
These employees routinely take advantage of wind direction to
minimize their exposure when possible.

Area concentrations of the treatment chemicals taken in various
occupied areas of the plant and critical downwind locations
generally indicate levels are very low and non-direct exposures
of other plant personnel are well below the accepted limits;

i. e., 10% or less (Tables 19, and 21). Concentrations downwind
are limited primarily because most emissions from cylinders

occur only for relatively short periods of time. At non-pressure
facilities,most airborne emissions occur downwind during the
second shift when there is little plant occupancy.

An area sample taken in a PCP block storage area, which is a
separate room of a treatment building, showed airborne levels of
11.4 pg/m?. This is not significant in terms of employee
exposures; however, it does indicate that sublimation occurs as
expected. Most treatment plants store blocks either under open
sheds or covered with plastic outside.

Wipe/touch sample analyses indicate that there are readily
quantifiable surface salts present (Table 24). The wide
difference in the metal concentrations for CCA treated wood

which had been water rinsed afterward may be attributed to the
extent of rinsing done. The results for the ACA treatment are,

in general, similar for the freshly treated and semi-dry material.
This data suggests likely skin contamination with the metal salts,
if the freshly treated wood is handled directly without gloves.

74


Warts, pigmented nevi, scars, and all other abnormal
skin lesions should be recorded on a body outline form
showing both front and back views (Eckardt, 1959).
Inquiry should be made at this examination as to how
any scar was obtained, since skin tumors or cancers
may have been removed by electro-cautery or excision
on an out-patient basis. The size of all lesions
should be measured and recorded so that any future
change in size can be noted. A careful examination
of the scrotum should be included. In addition, if
the worker has not received a chest x-ray within a
year, a pre-placement chest x-ray should be taken.

This is an excellent opportunity for the physician to
begin or supplement worker education by explaining the
nature of the materials to be handled and what effects
they may produce. The need to avoid unnecessary
exposure through protective equipment and/or good work
practices and personal hygiene can be emphasized.

2. Periodic Physical Examination

In addition to the regular physical examinations and
appropriate laboratory tests, the skin should be
examined at three to six month intervals, using the
body outline form described above. At these times the
education of the worker can be continued and reinforced.
Eventually, with a conscientious worker, periodic skin
examinations can probably be extended to once yearly.
Particular attention should be paid to skin lesions
that could be melanomas.

Chest x-rays should be repeated on an annual basis
or whenever the physician believes an indication exists
for it to be repeated.
The examining physician should be trained in the
identification of skin lesions that could be pre-
cancerous or cancerous, such as melanomas.
Sputum and urinary cytology examinations have been
suggested as additional tests by some authors, but
must be done under correct and appropriate test collection
methods.

Arsenicals
Analysis of hair samples
Urinalysis

SMA-12 Blood profile

84


Table 6. Preliminary Plant Surveys
TREATMENT wooD AGE OF WORKER
PLANT PROCESS PRESERVATIVE TREATED PRODUCTS PLANT TANK OR CYLINDER POPULATION
A Pressure PCP, type A,B,C, (wax) Bridge timbers, fencing, 20 years 1 - 4' x 50° 4 treaters
CCA Type Cc posts, playground equip- 1 - 6' x 50! 6*
Copper-8-quinolinolate ment, picnic tables,
truck beds.
B Non-pressure PCP, type A Poles 66 years 3-26'x26'x1l4' 2 treaters
(thermal) 1-12'x12'x107" 4-6%
1-14'x13'x50'
c Non-pressure PCP,Type A Poles 61 years 1-12'x12'xi02' 3 treaters
(thermal) 1-12'x12'x15!' 3-4%
D Pressure CCA Type C Fence posts, guard 20 years 1 - 6' x 40' 2 treaters
Creosote/ rails posts, 1 - 6' x 68° qe
Petroleum Oil (80/20) dimensional lumber 1 - 6' x 40!
a
E Non-pressure PCP, Type A Dimensional lumber 30 years 1-5'x5'x50' 1 treater

(vacuum)

4x

*others helping with loading/unloading tasks


PREFACE

The Occupational Safety and Health Act of 1970 emphasizes the
need to protect the health and safety of workers occupationally
exposed to a wide variety of potential hazards. The National
Institute for Occupational Safety and Health (NIOSH) implemented
this study to evaluate exposures to. wood treatment chemicals in
the wood processing and wood preservatives manufacturing plants
in response to the 1978 EPA Rebuttable Presumption Against
Reregistration (RPAR) of these materials. This technical report
on occupational health hazard assessment is a result of field,
literature, and laboratory studies. It addresses the classes of
materials presently in use in the wood treating industry for
long-term preservation purposes. The applications of wood
preservative chemicals as temporary treatment for molds and sap
stain control were not evaluated in the study because they do
not typically occur at wood treating plants or require the

same process techniques.

iii


absorbance at 254 nanometers of duplicate aliquots of the same
extract. A comparison of the two methods under field sampling
conditions was planned to determine if there was any correlation
between the two methods.

Pentachlorophenol --

PCP sampling was to be conducted on plant personnel by the
modified Dow silica gel procedure. Area sampling was planned
utilizing both the NIOSH and Dow methods side-by-side to
determine general airborne levels downwind in occupied plant
areas and further compare the reproducibility of the two
procedures.

Waterborne Systems --

Arsenic, chromates, and copper were scheduled for sampling and
analysis by the standard NIOSH methods using atomic absorption
spectroscopy. Air and filter wipe samples from freshly treated
or wet lumber were assayed identically. In ACA treating, some
airborne material was anticipated because pressure treatment

is done at elevated temperatures. Therefore, copper, arsenic,
and ammonia air sampling were planned. The latter was to be
done using Draeger length-of-stain tubes.

Ammonia levels at the ACA cylinders were to be checked
periodically during the cylinder door opening and while reloading
with fresh wood for the 15-20 minute interval required. CCA
treating done at ambient temperatures was expected to generate
little if any airborne materials based on the preliminary

survey and industry data. Personal sampling was scheduled
nevertheless.

62


These also help reduce exposure frequency and length during
eritical loading and unloading tasks. The hydraulically
operated bridge rails and doors further minimize the potential
for skin contact or clothing contamination which can occur when
these are done manually. To a lesser extent,it is also true of
automated gauging and control systems. Fewer actual depth
measurements are required in the preservative work or storage
tanks using the common line gauge.

The automated storage hopper/feed system developed for
transferring PCP flakes from storage to a mix tank has eliminated
manual bag dumping and the potential for the dust inhalation
exposure. The process is basically a closed system where solvent
or oil is pumped to the tank,heated,and recirculated until the
PCP is dissolved.

The single motor-driven movabhe platform in front of the
cylinder doors minimized the length of time they remain open.
For the pressure treatment processes done at elevated
temperatures such as - creosote, pentachlorophenol, and ACA -
it dramatically reduces both airborne emissions from the
cylinders and the employee critical exposure intervals.

Personal Protective Equipment --

Most plants provide the treating operators with eye protection,
gloves, boots and rain gear. Employees working at large
treatment plants usually are required to wear hard hats, safety
glasses and safety shoes. At some smaller plants, the use of
even minimal protective equipment is optional and left to the
discretion of the employees.

During emergency or cleanup situations, when an employee must
enter a cylinder or tank, respiratory gear and protective
clothing are usually available and used. It may vary from
organic vapor, acid mist, dual cartridge half-face respirators
to air line full-face canister respirators. In some plants,self
contained breathing apparatus was also available. Most plants
generally only had limited sophisticated respiratory protection
on hand for such purposes. Disposable coveralls or slicker suits
are also provided at some plants for vessel entry. Respirators
were not utilized at one plant. Company procedures required
that the cylinder be cooled down and aired out for a day or

two prior to entry. No incident requiring cylinder entry had
occurred for almost seven years at this plant. For routine
cylinder unloading tasks, various types of gloves are worn by
the treating operator or yard crew personnel who might come into
contact with freshly treated materials. In only a few instances,
the treater operator or yard crew did not use gloves when
handling treated lumber. With the exception of treater
personnel,many use the common work gloves primarily because of
the rough wood surfaces and splinters. Half-face dual

cartridge respirators were utilized during cylinder door opening

48


Chromosome aberrations have been noted in individuals treated
with arsenicals or occupationally exposed. The compounds have
also been shown to be fetotoxic and are considered teratogenic
by the EPA (PD 2/3, 1981).

Most health effects data generated by EPA and others are
concerned with the arsenical compounds in either the tri- or
pentavalent forms. Data on the carcinogenic, teratogenic, and
mutagenic effects or fetal toxicity of CCA, ACA, or FCAP
mixtures are lacking from either the industry or EPA. Plant
health records indicate that carcinogenic or teratogenic
effects have not been observed in employees exposed to the
arsenical mixtures either by inhalation or skin contact.
However, these were not elaborate epidemiology studies of
morbidity or mortality patterns in the industry.

Some studies have been done by EPA, the wood treating industry,
and state health departments on possible effects and potential

for skin contact and absorption when doing wood treating with

the water base mixtures. The efforts have been focused on
determining whether the material can be absorbed or adheres to

the skin. Limited animal studies have been conducted which
suggest there are no teratogenic effects from wood surfaces
treated with CCA (EPA PD 2/3, 1981). Direct application bioassays
of treating solutions to simulate skin contact with the wetted
wood surfaces have not been done by either the regulatory agencies,
companies, or the industry.

Health effects studies conducted by the industry and plant

site surveys by NIOSH did not demonstrate any significant air-
borne arsenical compounds resulting from wood treatment. Skin
contact potential and possible incidental ingestion have been
documented as a function of the wet wood surfaces and work
practites utilized in some plants. It is primarily associated
with the lack of use of impervious gloves when handling freshly
treated wood or solutions containing arsenical compounds.

The chromium used in CCA can be in the tri- or hexavalent state.
Industrial experience with exposures to the hexavalent chromium
has shown it produces ulceration of the skin and nasal mucosa
and perforation of the nasal septum (NIOSH, 1973). These are
commonly noted in the chrome plating industry and similar
applications where exposures to chromic acid mists occur.

Other acute health effects include nosebleed, persistent sore
throat, lacrimation and impaired sense of smell. In allergic
individuals, chromium has been shown to produce dermatitis
effects (NIOSH 1975c). There is human epidemiological data
suggesting that the hexavalent compounds are also carcinogens
affecting the respiratory tract (Ohsaki, et al, 1978). The
data is derived from the chromate processing and roasting industry
and the use of chromates as pigments in the paint and paper
industries.

22


Therefore, the same occupational limits used as a guide for health
risk control purposes are appropriate based on composition

and uses, boiling range, and plant experience. This conservative
approach is based, in part, on historic human experience related
to the compounds and mixtures present in creosote, and on
documented health effects which have occurred in the Shale oil,
slack wax and other industries and occupations (Mauro, 1951;
Shambaugh, 1935; Combes, 1954).

A number of occupational exposure surveys to creosote materials
in wood treating operations have been conducted. Some were
NIOSH Health Hazard Evaluations (Markel et al, 1975, 1977).
Others done in late 1978 and 1979 by the wood treating industry
were in response to the EPA-RPAR on the wood preservatives.
Generally, the data indicate that most personal exposures do not
routinely exceed the current coal tar pitch volatile (CTPV)
occupational standard of 0.2 mg/m3. There were a few high
values reported which the investigators felt were due to sample
contamination. All the creosote exposure data generated in both
the Health Hazard Evaluations and industry studies utilized the
NIOSH cyclohexane extraction gravimetric procedure. That data
indicates the personnel most exposed are those working adjacent
to the pressure cylinders during the opening, wood removal, and
re-filling tasks. Other more remote personnel assisting in
loading and unloading, sorting timber, etc., appeared to have
less exposure, and these were consistently well below the

limits for benzene soluble airborne particulates.

Creosote is commonly handled and controlled occupationally as
though similar to coal tar in health effects as a contact
irritant, photosensitizer, and potential carcinogen with
routine, prolonged contact, or inhalation. There is neither
positive nor negative human experience data in the wood
treating industry to indicate that additional or less
restrictive exposure control is appropriate.

PENTACHLOROPHENOL

The composition of technical grade PCP is approximately 90%
pentachlorophenol. The tri- and tetra- homologs comprise most
of the remaining 10%. Dioxins and dibenzofurans have also been
quantified as side reaction products; however, they are

present at less than one percent (Buser and Bosshardt, 1976;
Johnson 1978c).

The acute toxicity effects reported from plant experience with
PCP exposure are basically attributable to the pentachlorophenol
and the tri- and tetrachloro isomer secondary reaction products
rather than the dioxins or dibenzofurans (Menon, 1958; Robson,

et al 1969). The material used in the treatment plant

has been shown to be toxic by both inhalation and dermal
absorption in addition to its skin irritating and photosensitizing
properties.

18


This sampling was done at flow rates of 1.5 liters per minute.
Large size silica gel adsorption tubes (260/520 mg) were used
to collect pentachlorophenol at 0.5 liters per minute by the
Dow procedure. Capped tubes were submitted directly to the
laboratory for analysis.

Creosote --

The NIOSH Sampling and Analytical Method P & CAM 217 (coal tar
pitch volatile cyclohexane extractables) was utilized for
determining airborne levels of creosote. A glass fiber Type A
prefilter was used,with a 0.8 micron silver membrane filter
underneath,on a cellulose back-up pad. Samples were collected
in a 37 mm three-piece, closed-face cassettes at air flow rates
of 1.5-2.0 liters per minute. Filter materials were analyzed
gravimetrically after ultrasonic extraction with 5 ml of
cyclohexane. One-milliliter aliquots, taken to dryness under
Nitrogen,were used for the gravimetric determination of extract
residues.

Arsenical solutions --

ACA and CCA treatment materials were evaluated using the NIOSH
P & CAM 173 air sampling method for copper and chromium and
8-309 for arsenic. Initially, two techniques were used for
chromates determinations; i. e., P & CAM 173 for total chromium
and 169, which is specific for hexavalent chromium. These
samples were collected for analysis on a 0.8 micron mixed
cellulose ester membrane filter with a cellulose back-up pad

in 37 mm, three-piece, closed-face cassettes, at air flow rates
of 1.5-2.0 liters per minute. Sampling for hexavalent chromium
by the P & CAM 169 method was done with 5.0 micron PVC filters.
Ammonia levels in the ACA process were evaluated by grab
sampling with Draeger length-of-stain detector tubes. Wipe/touch
samples from ACA and CCA treated wood were taken with Whatman
No. 1 filter papers for analysis of the trace metals. Touch
samples are a modification of the usual wipe sampling procedure.
This was necessary because the treated wood was sampled while
still wet from immersion in the pressure vessel. Wiping
resulted in abrading of the paper so the procedure required
repeated pressing of the paper in different locations until
approximately 100 square inches of wood surface was sampled

(10 times for the 9 cm diameter: paper used).

Pentachlorophenol
Analytical Procedures NIOSH #S-297 -- At the end of monitoring,
bubbler solutions and prefilter were transferred to glass jars.

The jars were covered with polyethylene and capped for shipment
to the analytical laboratory.

30


Table 10. Airborne Concentrations of ACA

Treatment Air concentration
Sample Location Plant Component ye/m
Adjacent cylinder K Arsenic <13.6
door opening Copper <90.9
Top of freshly K Arsenic <0.3
treated lumber Copper <2.0
Copper TLV 1000 ug/m?
Trivalent Chromium TLV 500 pg/m?
Hexavalent Chromium TLV 50 yug/m?
Arsenic TLV 200 ng/m®

Wipe Sample Analyses --

Wipe samples were taken from dried ACA and CCA treated materials
to determine the presence of residual salts on the wood surface.
The results are summarized in Table ll.

Table 11. Wipe Sample Analyses

Treatment Quantity Measured

Sample Description Plant Component ug
Air-dried CCA K Copper 19
treated material Total Chromium 37

Arsenic 29
Air-dried ACA K Copper 100
treated material Arsenic 55
Air-dried ACA K Copper 240
treated material Arsenic 150

54


Table 20. PCP Pressure Treatment Facilities

Employee Exposure Levels

Task
Job Classification Treatment Plant Evaluated

Sampling
Time (Min.)

Air Concentration
Dow Method (ig/m°)

Treatment KK Cylinder opening 20 132.9
Operator and unloading 23 15.1
54 142.1
MM 42 22.8
34 12.6
64 12.6t
Cylinder opening 255 19.5
& routine tasks 462 10.17
Treatment Cylinder opening 20 74.9
Helper KK and unloading 19 71.3
Yardman KK Unloading tram 207 5.1
cars 207 14.5
Switchman MM Cylinder unloading 54 197.2
43 16.7
34 25.9
64 72.3t
Routine tasks 278 19.3
373 18.6+

+ Cellon Process

72


Contact with zinc chloride may cause burns and skin lesions
(Prasad, 1966). Inhalation of zine chloride in sufficient
concentrations can cause cyanosis, pulmonary fibrosis, necrosis,
edema, subglottic stenosis, bronchopneumonia, and can prove
fatal depending on the level and length of exposure (Evans, 1943;
Risher, 1974; Hunter, 1955; Johnson and Stonehill, 1961;
Whitaker, 1945; Wolf, 1975). Zine chloride has not been shown
to be mutagenic (Sirover and Loeb, 1976). In one study,
pulmonary adenomas, mammary, uterine, bone marrow and other
cancers were reported in tumor-susceptible mice given potable
water containing 10-20 mg/liter zinc chloride for five or more
months. Off-spring developed tumors more frequently than

their parents.

24


REFERENCES

Knudsen, I., H.G. Verschuuren, E.M. Den Tonkelaar, R. Kroes and
P.F.W. Helleman. 1974. Short-term toxicity of pentachloro-
phenol in rats. Toxicol. 2: 141-152.

Lorenz, L.F. and L.R. Gjovik 1972. Analyzing Creosote by Gas
Chromatography: Relationship to Creosote Specifications.
Proceedings of the American Wood-Preservers' Association
68, 32 - 42.

Markel, H.G., Jr., R.N. Ligo, and J.B. Lucas 1977. Health Hazard
Evaluation/Toxicity Determination Report. H.H.E. 75-117-372,
Koppers Company, Inc. North Little Rock, Arkansas. National
Institute for Occupational Safety and Health, Cincinnati, Ohio.

Mauro, V. Precancerous skin manifestations in workers employed
in distilling tar. Folio Medica, 34 (6): 281-296. 1951.

MITRE Corporation. The Analysis of Existing Wood Preserving
Techniques and Possible Alternatives. U.S. Environmental
Protection Agency, Contract No. 68-01-4310

Menon, J.A. 1958. Tropical hazards associated with the use of
pentachlorophenol. Br. Med. J. 1: 1156-1158.

NAS (National Academy of Sciences) 1977. Drinking water and
health. NTIS Report PB 270 422.

NCI (National Cancer Institute) 1978. Office of Cancer
Communications, Bethesda, Md. Private Communication.
October 27, 1978.

NIOSH (National Institute for Occupational Safety and Health)
1973. Criteria for a recommended standard. Occupational
Exposure to chromic acids. Publication under contract HSM
73-11021.

NIOSH (National Institute of Occupational Safety and Health) 1975a.
Criteria for a recommended standard . . . Occupational exposure
to inorganic arsenic. HEW Publication No. (NIOSH) 75-149. U.S.
Department of Health, Education and Welfare. Rockville,
Maryland.

90


Two additional pressure treatment Processes, the Lowry and the
Reuping, were developed in the early years of this century. These
are empty cell treatments in which the excess preservative is
removed from the wood cells in the final vacuum phase of the
process, leaving them coated rather than filled with treatment
solution. Since less preservative was used, overall treatment
costs were significantly reduced.

In the Lowry Process, the preservative is injected into the wood
in the treatment vessel under high pressure and temperature
conditions. The air naturally present in the wood is compressed
in the injection process. To complete the treatment process,
the pressure is released and the cylinder drained. The excess
preservative is forced out of the wood by expansion of the
compressed air. The only major variation in the Reuping Process
is an initial application of pressure in the range of 25-75 psi
prior to flooding the cylinder with creosote (Hunt and Garrett,
1967).

Solutions of creosote with crude coal tar or petroleum oils were
also found to be effective and less costly alternatives for wood
treating. As a result, creosote pressure applications by the
empty cell method have predominated in the railroad industry since
the 1920's (Ernst and Ernst, 1977).

The aqueous arsenical wood preservatives were developed in the
1930's. These chemicals consist of mixtures of compounds of
bivalent copper, pentavalent arsenic, hexavalent chromium or
fluorides. They typically impart a green-brown color to the wood
and provide a clean paintable surface. They have only been used
commercially by empty-cell pressure treatment methods in the
United States.

Pentachlorophenol (PCP) has been in use since 1947 for commercial
wood preservation purposes. It is applied in heavy to light
petroleum carriers or solvents by both pressure and non-pressure
methods.

All of these briefly described treatment chemicals are commonly
used for utility poles, lumber, posts, and numerous other wood
products. Few, if any railroad ties are treated with PCP or the
arsenical chemicals because they impart brittleness to the wood
causing excessive wear and splitting from the repeated compression
and expansion.


Table 22. CCA Pressure Treatment Facility (Plant KK)
Employee Exposure Levels
Job Task Sampling Air Concentration (mg/m*)
Classification Evaluated Time (Min.) Copper Chromium Arsenic
Treatment Cylinder opening 18 <0.062 <0.031 <0.009
Operator and unloading 72 <0.014 <0.007 3.265
Treatment Cylinder opening 18 <0.056 <0.028 <0.008
Helper and unloading 80 0.069 0.006 0.004
Table 23. ACA Pressure Treatment Facility (Plant KK)
Employee Exposure Levels
Job Task Sampling Air Concentration (mg/m”)
Classification Evaluated Time (Min. ) Arsenic Copper
Treatment Cylinder opening 29 <0.005 <0.034
Operator and unloading 25 <0.006 <0.040
Treatment Cylinder opening 27 <0.006 <0.038
and unloading 26 <0.006 <0.040

Helper

73


the greater potential for significant exposure. These operations
are more automated and,where possible,are closed systems. There
is significant emphasis on health and safety hazard control
during both routine tasks and unique situations where equipment
plugging or leaks occur.

In most of the plants surveyed, the use of respiratory protective
equipment is very limited or totally lacking. The air monitoring
data from the critical short-term tasks suggests that this is
appropriate for routine operations. The exception was an ACA
process where a NIOSH-approved respirator for ammonia fumes

was utilized when unloading the cylinder. The air monitoring
data indicated the personal protective equipment was necessary
for the treating plant operations to preclude overexposures and
significant eye irritation.

Most, but not all, plants have respiratory protective equipment
for use when cylinder or tank entry is necessary for dislodging
jammed wood products or other non-routine events,such as pump
leaks and spill clean-up. Protection of personnel during these
situations varied from the use of self-contained breathing
apparatus and impervious suits or disposable coveralls to no
personal respiratory gear and ordinary work coveralls.

Entry tasks and spill clean-up were not monitored during the
comprehensive surveys, because their occurrence is infrequent

and did not happen while at the plant sites. They were

observed during preliminary surveys while conducting general area
sampling and are the exposures of most significant concern in
wood treating operations. It is more critical at the smaller
plants where protective equipment and the training of personnel
tends to be less elaborate or non-existent. Larger plants
usually have more sophistication in the area of safety and health
hazard control particularly those which are subsidiaries of large
corporations. These plants generally have adequate emergency
equipment for unique exposure situations, whether they are entry
of tanks, major maintenance of equipment, or pump leaks and
spills. During both survey phases, however, it was noted that
personal protective equipment,even in large plants,is not

always utilized when needed for exposure control. This is more
evident with skin protection than the use of respirators, etc.

Exposure risk through skin contact, incidental ingestion,and
dermal absorption was evaluated by observation and queries at
all plant sites and materials. Treater operators and assisting
personnel almost without exception used gloves during pressure
cylinder opening or removal of wood from tanks, butt and full-
length. They vary from inexpensive cloth work gloves which are
disposed of when obviously soiled to impervious gloves of
various types. The locomotive crew or yard personnel assisting
in these tasks have a greater potential for this type of
exposure since their use of skin protection is more variable.

79


INTRODUCTION

The wood preservation treatment industry, on a national basis,
processed an estimated 350,970,000 cubic feet of wood products
in 1979. There is limited occupational exposure data, however,
on workers routinely using the water and oil-borne preservative
chemicals in spite of their toxicity. This is primarily because
the employee groups at individual plants are small. In the last
century, most of the commercial operations were family-owned.
Since World War II, greater automation, while not dramatically
changing processes or materials, has generally increased plant
size, capacity, and capital requirements. Consequently, larger
companies now process a majority of the total wood treated in
the United States.

The National Institute for Occupational Safety and Health, as
part of its responsibility for research in areas of occupational
concern, contracted with Stewart-Todd Associates to study and
evaluate occupational exposures and health risk in the wood
treatment industry. This project was funded as the first agent
of NIOSH Contract No. 210-78-0060, “Industrial Hygiene Assessment
of New Agents - III."

Eleven treatment plants and two preservative chemical manufacturing
operations were surveyed during the preliminary phase of the study.
In the preliminary field survey phase of the study, only one

plant site where the waterborne salt mixtures are manufactured

was included. The increasing use of these types of wood
preservative chemicals would normally warrant additional

follow-up comprehensive surveys of these facilities. However,
there are only three such installations in the United States and
the total numbers of workers did not justify follow-up work in

this segment of the preservative industry.

The facilities wereselected on the basis of treatment process,
preservative chemicals in use, geographical distribution, size of
work force, and other parameters. General area samples were taken
to evaluate different air sampling methods, define analytical
limitations, and obtain a range of potential exposure levels during
critical short-term tasks. Employee training and general occupa-
tional education efforts were evaluated along with historical data
and experience from safety and health monitoring. These initial
surveys provided the basis for the comprehensive phase of the
study in which personal exposure monitoring was conducted at four
treatment plants.


Table 24. Wipe/Touch Samples From
CCA and ACA Treated Wood

(Plant KK)
Treatment Treated Quantity Measured (1g)
Process Wood Condition Arsenic Copper Chromium
ACA Freshly treated 53 38
15 9.8
Semi-dry 0.94 3.3
0.76 3.4
64.0 110.0
CCA Rinsed/dry 41 13 65
Rinsed/wet 7.1 5.9 21
64 55 65
280 290 300

77


REFERENCES

Buser, H. and H.P. Bosshardt. Determination of Polychlorinated
Dibenzo-p-dioxin and Dibenzofurans in Commercial Pentachloro-
phenols by Combined Gas Chromatograph-Mass Spectrometry.
Jour. of the ADAC, 59 (3): pp. 562-569. 1976.

Campbell, J.B. 1970. Pneumatocoele formation following hydro-
carbon ingestion. Am. Rev. Resp. Dis. 101: 414-418.

Carnow, B.W. (Ed.), 1975. Health Effects of Occupational Lead and
Arsenic Exposure - A Symposium. U.S. Department of Health,
Education and Welfare, Rockville, Maryland. Final Report
under Contract 210-75-0026. HEW Publication No. (NIOSH)
76-134.

Cirelli, D.P. 1978. Pentachlorophenol: Chemistry, Pharmacology,
and Environmental Toxicology. K. Kanga Rao. Ed. Plenum
Press. New York

Combes, Frank C., M.D. Coal Tar and Cutaneous Carcinogenesis in
Industry, 1954. Charles C. Thomas

Deichmann, W.W. Machle, K.V. Kitzmiller and G. Thomas 1942,
Acute and chronic effects of pentachlorophenol upon
experimental animals. J. Pharmacol. Exp. Therap. 76: 104-117

EPA, Creosote Inorganic Arsenicals Pentachlorophenol, Position
Document No. 2, January, 1981

Evans, E.H. 1945. Casualties following exposure to zinc
chloride smoke. Lancet 249: 368-370.

Fisher, H., 1974. Morphology of lethal zinc-chloride-smoke
intoxication of the lung. Pneumonologie 150: 171-172 (German)

Fuller, B., R. Holberger, D. Carstea, J. Cross, R. Berman and
P. Walker 1977. The analysis of Existing Wood Preserving
Techniques and Possible Alternatives. MITRE Technical Report
7520. Prepared for the U.S. Environmental Protection Agency.
Final Report under Contract No. 68-01-4310. METREK Division/
The MITRE Corporation, McLean, Virginia.

Gill, T.G., and R.B. Phelps, 1974. Wood Preservation Statistics,

1973. Published in American Wood Preservers' Association
Proceedings. 70th Annual Meeting, Washington, D.C.

88


the moisture content of the wood and the rate of preservative
solution absorption. During colder months, the plant shuts
down because it lacks the capability to heat the vacuum
chamber to assure adequate moisture removal and penetration of
the treatment solution.

Engineering Controls --

The newer custom forklift vehicles and mobile cranes have
replaced many of the former manual or boom transfer tasks.
Accordingly, this has reduced the number of workers and the
time period during which they are potentially exposed to the
preservatives, either by inhalation or skin contact.

No other specific engineering controls, such.as modified pumps,
seals, etc. have been designed to minimize exposure to the treat—
ment materials. The natural ventilation of these outdoor
facilities assists in reducing airborne materials during the
treatment cycle and when unloading treated wood from tanks.

One plant, which is primarily a pressure treating facility, had
a hydraulically operated butt treatment tank for poles. It
dramatically reduced loading and unloading time in proximity to
the tank. This system loads poles horizontally with large
forklifts on a large hydraulically raised steel frame. The
poles are chained in place, and the stack is raised vertically
while lowering it into the butt treatment tank. The tank was
not in actual use during the on-site survey, which precluded
sample comparison. However, the transfer mechanism and
procedure was demonstrated while on-site.

Personal Protective Equipment --

Two of the three thermal treatment plants require hardhats in
the operations areas. Eye protection is generally encouraged at
all plants, but is not required. Goggles or face shields and
gloves are provided, but are used at the employees' discretion.
Some facilities also provide half-face chemical cartridge
respirators for treatment personnel or yard crew potentially
exposed to airborne treatment chemicals. Usually, their use

is optional.

Street clothing or personal coveralls are typically worn on
the job. Shower and change room facilities are provided at
some plants, but are utilized only to a limited extent.
Employees are encouraged to wash hands and faces at lunch
breaks and before leaving the plant at the end of the day.

Medical, Industrial Hygiene and Safety Programs --
None of these non-pressure plants have formal medical monitoring
programs. Pre-employment examinations are required at one

facility, but are oriented to physical health limitations which
might affect an individual's capability to do a specific task.

56


Table 8. Airborne Concentrations of Creosote
(CTPV) TLV 0.2 mg/m?

Treatment NIOSH P & CAM #217 UV METHOD

Sample Location Plant (mg) ** (mg/m?) (mg/m?)
Treatment building F -0.3t
adjacent pumps and
valving H -0.015*

H 0.23%

J -0.04%

J -0.011*
Adjacent cylinder H -0.045*
door opening

K 3.94 0.66
Top of freshly F 0.39
treated wood

G -0.3T

G -0.6T

H 0.59%

K 2.12 9.71

tsoxhlet extraction was utilized instead of ultrasonic procedure;

vial was used for gravimetric

assay instead of teflon boat.

*aluminum boat was used for gravimetric assay.

**blank values were greater than sample levels and gave overall

negative results.

52


Sodium pentachlorophenate is used as water solutions and applied
primarily at milling operations rather than wood treatment plants
per se. It is applied by dipping or spraying the surface of green
lumber and poles to prevent blue sap stain resulting from fungal
growth during storage or transportation. Approximately 1.2
million pounds of sodium-penta are produced annually and used for
this purpose (USDA-States-EPA Preservative Chemicals RPAR
Assessment Team Report).

INORGANIC ARSENICAL MIXTURES

The arsenical preservative chemicals are dissolved in water or in
water containing either ammonia or acidic compounds to keep the
preservatives in solution for good penetration. There are three
arsenical mixtures presently used for commercial wood treatment
in the United States. They are Chromated Copper Arsenate (CCA),
Types A, B, or C; Ammoniacal Copper Arsenate (ACA); and Fluor-
chrome-arsenate phenol (FCAP). The AWPA specifications for these
chemicals are described in Table III.

Table 3. AWPA Specifications P5 for Waterborne Preservatives

Preservative (%)

ACA ccA FCAP
COMPONENT Type A Type B Type C
Copper as CuO 47.7 16.0 18.0 17.0
20.9 22.0 21.0
49.8 18.1 19.6 18.5
Hexavalent 59.4 33.0 44.5 33.0
Chromium 69.3 38. 50.5 4l.
as Cro03 65.5 35.3 47.5
Arsenic 47.6 14.7 42.0 30.0 22.0
as ASj05 19.7 48. 38. 28.
50.2 16.4 45.1 34.0
Fluoride 20.0
as F 24.
22.0
Dinitrophenol 14.0
18.
16.0

1. Upper number is minimum content of the solid preservative.
Two numbers indicate extreme allowable range (minimum and
maximum).

2. Lower number is defined as content of the solid preservative.

Source: American Wood Preservers' Association (1974a).
14



To illustrate, a seal leak occurred during the preliminary
survey. It emphasized the need for readily available
respiratory and other personal protective equipment. The
employees, in this instance, after donning respirators, goggles,
and rubber gloves,immediately began the necessary repair work.

Plant personnel are periodically trained in the proper use of
the protective gear and the handling of hazardous chemicals.
Respirators are field fit-tested by the negative/positive
pressure technique. Safety showers and eye washes are located
on each level of the production unit. Shower facilities and
change room, with a dual locker system to separate street and
work clothing, are provided.

Medical, Industrial Hygiene, and Safety Programs--

Pre-employment and periodic physical examinations are required
for all employees in the PCP plant. Medical tests routinely
conducted include chest x-ray, audiogram, vision, pulmonary
function, complete blood counts, liver function tests, and
urinalysis. A physician from a local medical center is on

call for all medical treatment. The plant has an industrial
hygienist on site since 1978. He is responsible for conducting
air monitoring and evaluating occupational exposures throughout
the plant.

Monthly management/union safety meetings are held and periodic
walk-through inspections of the plant are conducted. All new
employees are given an initial safety orientation. Safety and
health issues are discussed, including the proper handling of
PCP, routes of potential exposure, proper work practices, and
personal hygiene.

Air Sampling Results--

Area air samples were done at locations throughout the
production unit where the most significant employee exposures
were anticipated to occur. These were adjacent to the sampling
ports at the primary and secondary chlorinator and on the
molten product side of the crystallization equipment. Product
stream samples were collected at both the primary and secondary
chlorinator while air sampling was conducted. Duplicate
samples were taken side-by-side using the NIOSH and DOW methods.
The analytical results for all samples taken were below the
limits of detection. One bubbler sample was lost in transit
and another sampling pump was not functioning properly on the
day of the survey. Therefore, only one quantitative PCP
determination was possible by the NIOSH method. Since no PCP
was found by this or the DOW method, there was no numerical
basis for comparison of the two sampling and analytical
procedures.

43


length of treatment cycles. Only one smaller plant had a
single track for each cylinder requiring the unloading of the
freshly treated bundles of material prior to reloading the tram
cars for the next treatment cycle. Another large plant had
decreased the other end of the unloading time to five minutes
with a motor-driven movable platform in front of the four
pressure cylinders. It permitted tram cars of treated or
untreated wood to be moved in or out of any one of the
cylinders with only two feeder tracks. It significantly
decreased unloading and rechanging time requirements which are
the critical treatment chemical exposure periods. Pressure
cylinders at plants always have the doors open outside the
treatment building to take advantage of natural dilution
ventilation. The length of the cylinder that is enclosed in

a building can vary from the butt end to the entire length but
not the door.

Most treatment plants using pentachlorophenol or creosote had
provisions fer collecting storm water runoff and a water
treatment area which could be an oil separator, evaporation pond,
or aeration tower. Plants where the waterborne arsenicals were
in use typically had a drainage basin around the cylinder to
collect leaking or spilling solutions from the cylinder and
storm water runoff. It was recirculated to the work tank for
use in diluting the purchased concentrate materials as needed.

Equipment breakdown occurred at some of the plants during the
preliminary surveys. They were generally limited to pump seal
or gasket leaks and mechanical problems with cylinder drainage.
In most cases, treatment operators and maintenance employees
worked together to make the needed repairs. Generally,
breakdowns with any of the equipment used for oilborne pre-
servatives significantly contributes to housekeeping and waste
disposal problems. They were more common with the oilborne
treatment plants primarily because the waterborne arsenical
systems are newer and have more automated equipment.

Engineering Controls --

Many engineering modifications had been installed in several
plants over the past several years for the combined purpose of
increasing productivity, and decreasing wood treatment costs.
They are listed as follows:

° hydraulically operated bridge rails

° hydraulically operated treatment cylinder doors

° automated gauging and control systems

° automated storage hopper/feed system for preparing
PCP/oil solution (penta flakes)

° motor-driven movable platform for loading and

unloading tram cars

47


Table 21. PCP Pressure Treatment Facilities
General Area Samples
Air Concentrations (g/m*)

Sample Description Treatment Plant Sampling Time (Min.) NIOSH Gravimetric Dow Method
Framing Operation KK 197 1.2
adjacent Treatment
Plant
Pole Storage Area

MM 362 <17.5 7.0

Downwind 50-60 Feet

76


Most previous statistics compiled by the AWPA have been under-
reported as a result of poor response to annual survey

questionnaires. The Assessment Team conducted a supplemental
survey to obtain missing information through contacts with
non-respondents and respondents. The final production totals

listed in Table 1, however, are still believed to be conservative.

Table 1. Estimated production of treated wood, 1978a/
(1,000 cubic feet)

Treated with

All Creosote Penta CCA/ACA/FCAP

Products Preservatives Solutions
All Products 327,486b/ 154,587 79,996 92,903
Crossties and

switchties ¢/ 106,085 103,138 449 2,498
Poles 64,179 18,237 41,905 4,038
Crossarms 1,685 41 1,615 29
Piling 12,090 9,993 1,154 943
Lumber & Timbers 105,305 10,780 21,209 73,317
Fence Posts 20,028 4,584 10,983 4,461
Other productsd/ 18,113 7,815 2,681 7,616

a/ Volume reported for 1977 (AWPA), plus volume reported by
respondents to Assessment Team Survey, plus volume estimated for
non-respondents.

b/ Creosote, Penta, and CCA/ACA/FCAP only.

c/ Includes landscape ties.

‘a/ Includes plywood.

Source: Phase I, NIOSH Contract No. 210-78-0060


Evaluation of Preliminary Results --

Pentachlorophenol-- Samples collected in the treating building
were taken at approximately breathing zone height and represent
exposure levels anticipated for the treater operators when
working in this area during routine operations. Airborne levels
were below the limits of analytical detection by both the NIOSH
and Dow procedures. Subjectively,there is no odor of oil or PCP
in any of the treater control rooms surveyed.

Samples taken adjacent to the cylinder door and on top of the
freshly treated wood represent maximum peak exposures expected
during the brief critical task periods usually of less than 30
minutes. These should only occur when they are working in close
proximity to and downwind of the cylinders or treated wood. The
air concentrations varied considerably depending on wind direction
and velocity. Visible fume and steam emissions are evident when
cylinder doors are opened. There is also a distinct PCP odor
downwind during unloading operations of both pressure and
non-pressure vessels.

The air sample results ranged from 0.01 to 0.51 mg/m3 for the
various locations and monitoring techniques. Generally, samples
collected by the Dow method and the sodium hydroxide bubbler
method showed better correlation than the Dow and NIOSH methods.
The data (Table 7),however, is too limited to make any
statistical judgements. The quality of the analysis work at
the original subcontracting laboratory precludes a realistic
comparison of the methods.

Creosote-- Seven of twelve air samples collected and analyzed

by the NIOSH P & CAM 217 method gave negative results even though
visible fume and steam emissions are evident when the cylinder
door is opened. Therefore, these cannot be considered valid

data.

The remaining samples indicated airborne concentrations of

cyclohexane extractable hydrocarbons varying from 0.23 to
3.94 mg/m3. Some of these samples were taken at convenient

locations such as at the top of the cylinder door where maximum
‘airborne creosote might be expected and may not necessarily
reflect actual employee exposures. A sample taken inside the
treatment building at Plant H represents atypical conditions,
since a pump leak occurred on the day of the survey.

The lack of precision or of the data can be assigned to: (1) the
poor analytical sensitivity of the solvent extraction gravimetric
method (2) the inconsistent procedures followed by the analytical
laboratory. A secondary Ultraviolet Spectrophotometric method
was used on duplicate cyclohexane extracts of the creosote
samples collected at Plant K. Measurable quantities of cyclo-
hexane extractable hydrocarbons were found by both the
gravimetric and UV analysis procedures. There was, as expected
from previous laboratory work, no correlation between the data

by the two assay methods (Table 8).

51


11.
12.
13.
14.
15.
16.
17.
18.
to
20.
21.
22.
23.

24.

TA

Estimated Production of Tre
Comparison of Composition o

BLES

ated Wood, 1978 ......,
f£ Commercial Grade. . ...

and Purified Grade Pentachlorophenol (PCP)...

AWPA Specifications P5 for
Treatment Facilities Contac
Results of Analysis of Creo
by Ultraviolet Absorp
Preliminary Plant Surveys.
Airborne Concentrations of
Airborne Concentrations of
Airborne Concentrations of
Airborne Concentrations of
Arsenate (ACA)...
Wire Sample Analyses...
Airborne Concentrations of
Airborne Concentrations of
Wood Treatment Plants - Com
PCP Non-Pressure Treatment
(Plant CCO - Employee
PCP Non-Pressure Treatment
Area Monitoring Compa

Waterborne Preservatives. .
ted... . ee ee
sote Spiked Pilters 00.60
tion. . 2... 2... eee

Pentachlorophenol (PCP) . .
Creosote. ..

Chromate Coppen eeeneces (CCA)
Ammoniacal Copper .....

Pentachlorophenol .....
Creosote... .......
prehensive Phase. .....
Facility. .........

Exposure Levels. 0000
Facility (Plant cc) 0000
ring Sampling Procedures. .

PCP Non-Pressure Treatment Facility (Plant CC)... .
General Area Air Monitoring. ....... D
Creosote Pressure Treatment Facilities ..... .
Employee Exposure Levels ......... °
Creosote Pressure Treatment Facilities ..... .
General Area Samples ......... O d
PCP Pressure Treatment Facilities. ..... . .
Employee Exposure Levels . ..... or .
PCP Pressure Treatment Facilities. ....... .
General Area Samples... 09000 0
CCA Pressure Treatment Facility (Plant KK)... O
Employee Exposure Levels ......... o
ACA Pressure Treatment Facility (Plant KK) ...
Employee Exposure Levels ...

Wipe/Touch Samples from CCA and ACA Treated “Wood

(Plant KK) ........ ee Do 0

vi

13
26
36
39
50
52
53
54
54
57
58
65
67
68
69
70
75
72
76

73

77


Table 16. PCP Non-Pressure Treatment Facility (Plant CC)
Area Monitoring Comparing Sampling Procedures

Air Concentration (ug/m*)
Sample Description Sampling Time (Min.) DOW Method NIOSH Method

Downwind of butt dip
Treatment Tank

Distance 2 Feet 261 115.3 119.8
15 Feet 58 14.6 175.0

Downwind of full-length
Treatment Tank
Distance 75-100 Feet 281
75-100 Feet 165

oOo
wow
AN

68



There have been only a few plant exposure studies of hexavalent
chromium exposures in the wood preserving industry. Health
Hazard Evaluations conducted by Markel and Lucas in 1975

showed levels below the limit of detection at two sites. At two
other locations, levels were measurable in the range of the
current TLV.

The remaining component of the common waterborne treatment
chemicals is copper. It is an essential element for metabolism
in man (NAS, 1977). Exposure to inorganic copper at high levels
causes naso-laryngeal congestion and irritation with possible
ulceration and perforation of the nasal septum (Key, 1977).
Chronic exposure effects are reportedly rare. This is reflected
in the current occupational limit for copper when compared with
arsenic and hexavalent chromiun.

MISCELLANEOUS WOOD TREATING CHEMICALS

The remaining compounds commercially used in oil or waterborne
treatment are copper naphthenate, copper-8-quinolinolate,
tributyl tin oxide (TBTO), acid copper chromate (ACC), and
chromate zinc chloride (CZC).

Copper naphthenate has rather limited usage in the wood treating
industry. There is no human health effects data on the material
available from either the industry, regulatory agencies, or
others. Published data on this compound and copper~8-quinolino-
late are limited to animal studies indicating they are not acutely
toxic. Both compounds are primarily used as anti-fungal agents.

Tributyl tin oxide has even more limited use in the wood
preservation industry. It is an effective fungicide, particularly
in tropical or high humidity areas. Typically, it is used on
finished millwork. Animal toxicity data available on tributyl

tin oxide indicates it is an acute eye and nasal irritant

(NIOSH, 1976a). Severe exposures can result in nasal discharge
and reddening in addition to eye and upper respiratory irritation.
At higher concentrations or with prolonged excessive exposure,
irritation and tightness of chest occur. The material is
significantly toxic by oral administration and can result in eye
and general systemic effects on the kidneys and adrenals

(Anger, et al, 1976; NIOSH, 1976a). No other long-term effects
such as carcinogenesis, teratogenesis, or fetal toxicity have

been noted in the literature. This may be due to the limited use
of this material for either wood preservation or other applications.

There is presently no published information on potential health
effects or occupational exposure to acid copper chromate (ACC)
or chromate zinc chloride (CZC) wood treating solutions. The
effects of exposure can only be assumed based on the individual
components of the two systems. Copper and chromate have already
been discussed.

23


ANALYSIS OF RESULTS
Non-Pressure Treatment Plant

The personal breathing zone monitoring conducted at the PCP
non-pressure treatment facility (Table 15) indicates exposure
levels well below the current permissible occupational limit of
500 ug/m?. The pole inspector who does pole borings on the
treated wood to determine preservative penetration before they
are removed from the full length tank had one of the higher
exposures. However, it was only 34% of the regulatory limit.
The treater operators' exposures varied from 4.9 to 275 ug/m?
and the magnitude of exposure appears to be related to wind
direction and velocity. Most of the data obtained are indicative
of less than full shift during the most critical tasks in the
treating operation. With the exception of the second shift
treater operator, 8-hour, time-weighted average (TWA) exposures
probably are considerably less than the values shown.

General area samples taken in occupational areas in proximity
to the tanks and at locations downwind of treatment operations
show low air concentrations except in close proximity to tanks
(Tables 16 and 17). Downwind concentrations would be expected
to vary with wind velocity and distance. The treating building
typically downwind of the large treating tank had more
significant airborne levels of PCP but none of the areas
sampled approached the occupational limits.

Pressure Treatment Plants

Personal exposures to cyclohexane extractable hydrocarbons

by either method, PCP, and the arsenical, chromate compounds
were, in most instances, well within the respective permissible
occupational limits (Tables 18, 20, 22 and 23). Airborne trace
metals monitored at the ACA and CCA treatment operations were
generally below the limits of analytical detection.

The exceptions were a few samples from one creosote plant (JJ),
which showed excessive levels for two members of the locomotive
crew on midnight shift and a forklift operator during the
transfer of treated wood on day shift. These data are question-
able primarily because these personnel were more remote from
exposure sources during most of the sampling period and others
doing essentially identical tasks showed much lower exposures.

The other exception was a sample taken on a treatment operator
during a series of four CCA cylinder openings (Plant KK). No
chromium or copper was detected in the sample but the arsenic
level was exceptionally high. This also cannot be explained
because ,wwith high arsenic levels, some copper or chromium should
have been present in detectable quantities.

66


maximum temperature conditions. In contrast, the gravimetric
data showed highly variable airborne levels, with three of four
samples below the limits of detection even though fumes were
readily evident and the odors objectionable at the sampling
sites. The airborne concentrations in these locations should
represent maximum potential peak exposures for an employee
checking creosote levels in the tank from the downwind side.

The UV absorption data suggest concentration approaching the
limits for coal tar pitch volatiles.

59


FLUOR CHROME ARSENATE PHENOL --

FCAP is the oldest of the waterborne arsenical salt preservatives.
It is prepared from a soluble fluoride, hexavalent chromium,
pentavalent arsenic, and dinitrophenol, and shipped to treating
plants as a dry mixture. Since it can be leached from the
treated wood by water, it is used primarily for treatment of
lumber for above-ground applications. Due to its very limited
demand, there are no current figures available on annual usage.

OTHER PRESERVATIVE CHEMICALS --
Other wood preservatives which now have limited use include:

Acid Copper Chromate (ACC)

Chromated Zinc Chloride (CZC)

Copper Naphthenate

Copper-8-quinolinolate

Bis (tri-n-butyltin oxide) or more commonly called
tributyltin oxide (TBTO)

The first two are waterborne preservatives and the latter three
are oil soluble.

Copper naphthenate is a waxy compound that has a high toxicity
to wood-destroying fungi. It has also been used to augment
creosote treatment to provide additional protection against
marine borers. Its high cost, however, limits its use to
specific commercial applications such as park and recreation
equipment.

Copper-8-quinolinolate, combined with 2-ethyl hexoate, is only
slightly toxic to humans and is approved by FDA for treatment of
wood used in food applications. It has some use for outdoor
tables and similar wood articles.

TBTO, in light oil solutions, has extremely high fungal toxicity,
approximately ten times that of PCP. It is also less toxic and
irritating than PCP, in addition to having significantly better
painting characteristics. It is presently considerably more
expensive than PCP and not very effective for ground contact
applications. Therefore, it is not used extensively for commercial
applications. Only one plant was identified using this pre-
servative chemical in the United States.

HEALTH EFFECTS OF WOOD PRESERVATIVE CHEMICALS AND SOLUTIONS
CREOSOTE AND SOLUTIONS OF CREOSOTE

Creosote is a distillate fraction from coal tar, a by-product in
the conversion of coal to coke, which is used in the manufacture

of steel. However, the chemical distillate creosote is a coal-
derived product with a specific boiling range of 300° to 700°F.

16


derivatize the extracted compounds. The results of the prepared
randomly numbered sample analysis are as follows:

DOW METHOD NIOSH METHOD - S297
Quantity Analytical Quantity Analytical Volume
Spiked Result (ig) Spiked Result (1g) Submitted m1**
Blank 0.01 Blank 1. 14.3
Blank 0.01 Blank 10 14.3
0.10 0.06 5.1 6.0 8.4%
0.10 0.06 5.1 ilo 14.6
1.02 0.88 10.2 12.0 13.9%
1.02 1.02 10.2 10.0 14.5
10.2 13.0 20.4 21. 14.1
10.2 9.9 20.4 20. 14.3

*Samples leaked during shipment.

The analytical data, though lacking in numbers, showed improved
reproducibility, and sensitivities were as anticipated from
published results. Additional field survey work was scheduled
using both the NIOSH and DOW methods. The use of a prefilter

was no longer used for the silica gel since Dow and our laboratory
experience indicated the glass wool plug, if present, would
collect the airborne particulate pentachlorophenol. Limited
side-by-side area sampling by the two’ methods was done during
comprehensive surveys.

Alternate Pentachlorophenol Sampling and Analytical Methods --
During one preliminary field survey an alternate sampling and
analysis method for pentachlorophenol was utilized. It is the
bubbler method most commonly utilized by the wood treating
industry for area and personal sampling. PCP is collected in
15 milliliters of 0.1 Normal sodium hydroxide solution at an
air flow rate of 1.7-2.5 liters per minute. The solutions are
analyzed according to the method of Cranmer and Frael (1970)
using gas chromatography equipped with an electron capture
detector. The sensitivity of the method is estimated at 0.2
micrograms per sample.

Creosote Analysis NIOSH P & CAM 217 -- Creosote samples were
extracted with cyclohexane by ultrasonic agitation. One
milliliter of the extract was evaporated to dryness under
nitrogen in a tared teflon boat. The residue was determined
gravimetrically on a 6-place analytical balance.

During the initial field surveys of creosote treatment plants,
spurious analytical results were obtained with this method; i. e.
blank filters in some cases showed higher levels of cyclohexane
extractable material than samples taken adjacent to airborne
sources of creosote.

33


CCA Treatment Process -- Airborne trace metals from the CCA
process were monitored at only one location (Plant D). All
specific compounds analyzed were below the limits of analytical
detection, with the exception of a sample taken inside the
treatment building adjacent to a concentrate mix tank. Even

in this close proximity, the levels of hexavalent chromium and
arsenic were extremely low. Two sampling and analytical
procedures were used for evaluating airborne chromium
concentrations. Due to the difference in analytical sensitivity
and the limited number of samples taken, a comparison of
hexavalent and total chromium levels could not be made from
field sampling.

No visible emissions are evident during the unloading of CCA
treated wood from cylinders. The samples collected adjacent
to the cylinder door opening. and on the freshly treated wood
represent maximum potential airborne materials encountered by
operators or yard personnel while performing tasks of greatest
occupational concern. No measurable levels of CCA were
detectable (Table 9).

Table 9, Airborne Concentrations of CCA

Treatment Air concentration
Sample Location Plant Component ug/m?
Treatment Building D Total Chromium <1.9
adjacent concentrate Hexavalent chromium 0.3
mix tank Copper <0.9
Arsenic 0.9
Adjacent D Total Chromium <3.1
cylinder door Hexavalent chromium <0.2
opening Copper <1.5
Arsenic <0.6
Top of freshly D Total Chromium <3.3
treated wood Hexavalent chromium <0.3
Copper <1.7
Arsenic <0.7

ACA Treatment Process ~~ The ACA process was evaluated at only

one facility (Plant K) where it is used. Airborne levels of
arsenic and copper were below the limits of analytical detection
indicating that there are negligible emissions of trace metal
contaminants during cylinder opening. Ammonia levels were
readily evident by odor and eye irritation at the cylinder

door and adjacent to freshly treated wood (Table 10).

53


A number of acute occupational and non-occupational cases of
poisoning have occurred, several of which have been fatal
(Gordon, 1956: Menon, 1958). The acute cases documented have
occurred in applications where there was significant contact
and/or close proximity to obvious airborne sources such as

when spraying solutions of pentachlorophenol for wood preservative
surface treatment and in dipping operations. Most incidents
predate the mid 1960's. A later documented acute epidemic also
occurred when the material was inadvertently used as a dis-
infectant (Armstrong, 1969). In that instance, the symptoms
which occurred were from skin absorption and resulted in the
death of two infants. Other short-term effects published include
eye and upper respiratory irritation from the emissions of hot
treating solutions.

Severe dermatitis and neurological disturbances have been noted
in humans from chronic skin or inhalation exposure. Typically,
the first symptoms are bronchitis and/or chloracne. Generally,
when chronic symptoms occur, the recovery time is lengthy and

can require up to a year (Baader and Bauer, 1951). Other medical
problems which have been reported in man are reduction in libido
and central nervous system effects. The latter are somewhat

less certain since, in most instances, the exposures were not
exclusively to PCP (Campbell, 1952).

The symptoms observed in man from excessive acute or chronic
occupational exposures and accidental poisoning have basically
been duplicated in animals (Deichman, 1942; Knudsen, 1974:
Goldstein, 1977). The commercial product has been shown to be
highly toxic by ingestion, inhalation, skin contact, and
absorption for several species. There are no animal data
indicating that technical grade PCP is carcinogenic. Studies
have been done at dietary levels of up to 30 mg/kg per day for
rodents with no significant increase in the incidence of tumors
for the full lifetime of the animals (Schwetz, 1973; Johnson,
1978c). Similar results were obtained with mice. Dermal
applications did not promote tumorigenic activity when used

in conjunction with a known carcinogen in a single application
(Boutwell and Bosch, 1959).

Pentachlorophenol is included in the NCI Bio-assay Program. No
data indicating that PCP or the predominant secondary reaction
products have significant biological activity (NCI, 1978) has
been received.

In contrast, it has been demonstrated to be fetotoxic, causing
significant anomalies (Schwetz, 1974b; Hinkle, 1973). This
data is from studies of pregnant rats fed the material at
different levels during the critical states of gestation. Some
of the minor side reaction products in PCP are known to be
embryotoxic and possibly teratogenic when administered orally to
rodents (Schwetz, et al, 1973).

19


MEDICAL SURVEILLANCE

Pre-employment and periodic medical surveillance programs are
recommended based on potential health effects from airborne
exposure and contact with the treatment chemicals. This should
serve as a means of assuring that overexposure and health effects
are not occurring. It will also substantiate whether significant
skin contact and absorption, not quantifiable by air sampling,
occurs. The medical physical examinations should be oriented to
detect both the specific treatment chemical present in biological
fluids, where possible, and evaluate the more sensitive indicator
systems for signs of early reversible health changes.

86


Table 6. (Continued)

TREATMENT wooD AGE OF WORKER
PLANT PROCESS PRESERVATIVE TREATED PRODUCTS PLANT TANK OR CYLINDER POPULATION
F Pressure PCP (Type A) Poles, posts, 35 years 1 - 8' x 50° 4 treaters
Creosote/coal tar railroad ties, 1 - 8' x 60' 4k
(60/40) dimensional lumber, 2 - 8' x 135"
CCA Type C bridge timbers 1 - 8' x 185"
1 - 4" x 135'
G Pressure Creosote/coal tar Posts, mine & bridge 20 years 1- 4" x 50° 8 treaters
(80/20) timbers, building poles 1 - 6' x 50°
CCA and squares, railroad 1- 4' x 50'
ties 1x 4' x 70'
H Pressure PCP, Type A Poles, dimensional 80 years 1-9%' x 165! 5 treaters
Creosote/petroleum lumber, bridge timber, 1-8%' x 80' 3%
011(70/30, railroad ties 1-93" x 165"
50/50) Ss

‘others helping with loading/unloading tasks


pre-employment physical examinations to determine the suitability
of prospective candidates for exposure to the treatment chemicals.
Many pre-employment exams address only the prospective employees

suitability to lift heavy objects and general physical condition.

None of the medical programs at the treatment plant sites surveyed

in both phases of field work had elaborate medical surveillance
programs by current standards.

8l


Table 13. Airborne Concentrations of Creosote

Air Concentration (mg/m)

Treatment NIOSH UV METHOD
Sample Location Plant P & CAM 217
Adjacent butt treatment L <0.017 0.090
tank (downwind)
L 0.428 0.186
L <0.038 0.229
L <0.036 0.323

CTPV - TLV - 0.2 mg/m?

Analysis of Results--

Pentachlorophenol-- Samples taken in the control building of
the various processes are a reasonable estimate of average
exposure levels for an operator stationed there. Very little
time is spent in the thermal treatment process pump room except
for routine visits to check equipment periodically during the
treatment cycle.

Airborne pentachlorophenol concentrations varied from 0.04 to
0.36 mg/m* by the NIOSH Method and 0.09 to 1.33 mg/m? for the
Dow silica gel procedure. There was generally very poor
correlation between the two methods. This is due to the
mixing of analytical methods and PCP desorption problems
encountered by the analytical laboratory originally used. The
data from the NIOSH procedure indicates that potential peak
exposure levels are greatest at the vacuum chamber door opening
Levels in the pump room and adjacent to the tank were highest
when treating by the thermal process.

Creosote-- Samples collected downwind of the creosote thermal
treatment operation were analyzed by the NIOSH gravimetric
procedure with duplicate aliquots assayed by the UV absorption.
The data showed very poor correlation between methods of
quantifying creosote. The UV data indicates that airborne
levels downwind increased as the treatment tank was heated to

58


RECOMMENDATIONS

From the data and information collected in the preliminary and
comprehensive surveys, the following recommendations are presented
to further minimize potential employee exposures by all routes,
and provide adequate health surveillance as a secondary means

of monitoring health effects. Implementation needs will vary
between plants depending upon their current status and the
alternatives which provide the most optimum operating flexibility.

For creosote and pentachlorophenol pressure treatment plants, an
appropriate chemical cartridge full-face respirator should be
provided and used for emergency spills, pump leak correction,and
when entering cylinders for cleaning, dislodging wood,or replacing
broken tram car cables. Self-contained breathing apparatus or

air line respirators are preferred for the latter tasks. Full-
face canister respirators for ammonia fumes are necessary for
treatment operators during ACA cylinder opening and unloading.
Nuisance dust masks, NIOSH-approved disposable type, are
recommended when doing bag dumping of copper oxide at these plants.
Small plants using bags of flaked PCP should be requiring the use
of full-face respirators as described for spills, etc. when

doing these infrequent tasks.

When doing short-term cylinder entry tasks, disposable coveralls
or others which can be laundered should be utilized. Impervious
gear could be used but might result in excess heat burden except
when periodic cylinder shutdown, cleanup,and maintenance are done.
Observations made during the on-site surveys indicate there is
also some clothing contact with the treatment chemicals by yard
personnel involved doing loading and restacking of freshly treated
wood. We recommend that coveralls be provided and laundered
commercially to avoid taking the material home resulting in
household contamination. There should be a required change of
work clothes when they show obvious signs of contamination and

on a scheduled basis. Only street clothes should be worn to and
from the plant. Adequate work-street clothing change facilities
are needed at many of the plants to meet current guidelines.
Shower and wash-up facilities are needed adjacent to eating and
locker change areas. Some plants already have suitable facilities,
while in others these are minimal or non-existent. Some plants
have pressurized or air-conditioned treating control rooms for
breaks and lunch. They are satisfactory for these purposes if
good wash-up facilities are immediately adjacent, well cleaned,
maintained, and free of contaminants. We recommend positive
pressure control rooms for those facilities where operators must
eat while on duty.

82


The products and treatment chemicals in use at the facilities
surveyed are summarized as follows:

Pentachlorophenol poles and posts
dimension lumber
bridge timers

Creosote crossties
marine pilings
bridge timber
posts
building poles

Arsenicals building squares
(CCA and ACA) dimension lumber
poles

FCAP appears to have been replaced almost entirely by CCA.
Creosote,alone or in combination with coal tar or petroleum
oils, is commonly used.

SELECTION OF PRODUCERS

Creosote is the largest volume wood preservative in use. It is
produced at twenty-four plants in the United States. A creosote
manufacturer was initially considered for inclusion in the study
since the process is a fractionating operation using coal tar

as feed stock. However, during the initial treatment plant
surveys,it was learned that there is a variety of creosote blends
in use rather than just the distillate per se.

While the AWPA issues standards for creosote, they only include
ranges of physical characteristics, such as specific gravity,
distillation, percent water, and xylene insoluble material
(AWPA P1-78 Standard). The relative quantities and types of
hydrocarbons present will vary depending on several factors
including cost and availability of raw materials. The
evaluation of exposures at any creosote production facility may,
therefore, be quite different from others based on the chemical
makeup of the feedstock. In addition, creosote production
operations are typically automated with limited personnel and
infrequent exposures on the units except,possibly,when loading
trucks. Therefore, creosote was evaluated only at treatment
facilities where the potential for contact or airborne exposure
is more likely.

Pentachlorophenol is manufactured by three companies in the

United States. One plant producing penta flakes was evaluated
during the preliminary survey phase.

27


Also considered in the study was elaborate analysis of the
dioxin contaminants in pentachlorophenol (PCP) which pose the
greatest occupational concern. Data available from recent
literature, however, did not suggest it would be productive
to consider this type of analysis on the personal samples unless
they were significantly above the current occupational limits
for PCP. The dioxin concentrations in technical grade PCP or
extensively recycled preservative solutions are extremely low
and, therefore, it was apparent that no additional useful
information would be obtained from the costly analysis of new
or used materials from the treatment plants.

Work practice and medical monitoring guidelines are presented for
review by both the industry and the regulatory agencies since
very few of the plants surveyed or contacted had formal programs.
The best answer to the RPAR concerns expressed in the EPA
documents would be biological data indicating whether the

alleged health effects from the wood treatment chemicals

actually are occurring.


RESULTS OF PRELIMINARY SURVEYS

MANUFACTURING OPERATIONS
Pentachlorophenol

Only one pentachlorophenol manufacturer was included in the
preliminary phase of the study and, therefore, comparison with
other facilities process methods, engineering controls, work
practices, etc., cannot be made. The chlorination process is
essentially a closed system with the exception of sampling

ports for quality control purposes. Off gases from the reaction
are removed through an acid adsorber. The excess chlorine is
recycled back to the chlorinator and other by-product
contaminants are treated and pumped to a deep-well disposal
system.

Engineering Controls--

The pentachlorophenol crystallizing, finishing equipment, and
bagging and drum filling stations have local exhaust ventilation.
The air passes through a scrubbing and baghouse dust collection
system before venting to the roof. The exhaust equipment was
specifically installed for exposure control, but is designed

to minimize product losses. The production operation is

located in a single building which is enclosed only on two sides
with sheetmetal panels. It has open-grate floors throughout the
upper levels which maximizes natural dilution ventilation.

This serves as an important secondary control method in the
event equipment leaks occur.

Personal Protective Equipment--

Hardhats, safety glasses and shoes, and emergency escape
respirators are required for all employees in the pentachloro-
phenol plant at all times. Goggles, face shields, rubber boots,
and gloves are also available if needed or required for specific
tasks or operations. Slicker suits, canister respirators
approved for organic vapors and acid gasses, self contained
breathing apparatus, and air line respirators are also maintained
for non-routine, turnaround, or emergency purposes. The
corrosive nature of the raw materials, intermediate components,
by-products, and product, mandate routine equipment maintenance.

42


This report presents the following factors:
1. <A detailed description of treatment processes and chemicals.

Bo Documentation of current work practice and engineering
controls.

3. An evaluation of NIOSH and alternate sampling and
analytical procedures.

4. Documentation of typical inhalation exposure levels for
various treatment processes.

In reviewing analytical parameters for the creosote preservative
mixtures, various options were considered for determining
exposure risk from airborne or contacted materials. Of primary
concern with these types of hydrocarbon materials are the
polynuclear aromatic compounds. Elaborate individual polynuclear
analysis was considered for a variety of creosote mixtures
utilized in the industry and personal samples taken in the field.
However, it was not done for two basic reasons. First, the data
available from elaborate research studies on single or multiple
polynuclear 3-6 ring compounds indicate that additional specific
analysis does not provide insight in ranking the biological
activity of mixtures. This results from the fact that the
complex mixtures contain some known carcinogens such as benz
alpha pyrene (BAP), other materials which are co-carcinogens,
accelerators, and some 3, 4 and 5-ring compounds which are
inhibitors of the carcinogenic process.

In addition, the high cost of performing the elaborate or even
simple compound analysis for BAP on the variety of samples

taken did not appear warranted based on the additional
information it would provide on potential health risk to the
materials. We have treated creosote as though it had the

same carcinogenic potential as coal tar pitch volatiles in coking
oven operations. This may not be correct but it permits a
conservative approach to health risk control so long as it does
not place undue burden on the wood preservative chemical
manufacturers or users. In evaluating exposures to the water-
borne materials, one of the primary concerns was skin absorption
and/or incidental ingestion resulting from hand contamination
during handling of treated wood.

The procedures utilized to determine surface contamination do
not reflect quantitatively an index of personal exposure risk
but provide an indication of process steps and tasks of greatest
occupational concern. Recommendations to minimize these sources
of exposure risk are primarily oriented to work practice
modifications rather than specific engineering efforts per se.

A number of engineering alternatives are presented for future
plant modifications to make them cost effective in addition to
reducing the time or frequency of the most critical exposures of
concern.


Table 5. Results of Analyses of Creosote Spiked Filters
by Ultraviolet Absorption

Extracting Spike Amount (ug) Ultraviolet (yg) Extraction
Solution Efficiency
Benzene 50 33.5 67%
Benzene 100 65.5 65
Benzene 200 150 75
Benzene Blank 0

Benzene 50 33.5 67
Benzene 100 71 71
Benzene 200 185 92
Benzene Blank 0

Cyclohexane 50 27 54
Cyclohexane 100 58 58
Cyclohexane 200 140 70
Cyclohexane Blank i)

Cyclohexane 50 28 56
Cyclohexane 100 61.5 61
Cyclohexane 200 162 81
Cyclohexane 0 0

Both gravimetric and UV methods of creosote analysis were
utilized for the comprehensive field survey work in order to
provide further documentation on the data correlation by the
two analytical techniques.

Spiked filters, along with bulk samples, were submitted to
another certified laboratory for both gravimetric analysis by
the NIOSH method and follow-up UV analysis of the cyclohexane
extract at 252 nanometers. Those results also showed no
correlation between the amount of material on the filter and
the gravimetric results. Creosote quantities per filter ranged
from 27-214 micrograms.

In contrast, the secondary UV analysis showed a correlation
coefficient of 0.997 with lower detection limits of 4-6 ug per
analyte. The limited data suggests that recovery improves as
quantity per filter increase. Only approximately 65% recoveries
were obtained at the 27 wg levels. At higher concentrations,
the extraction recovery was slightly increased.

Analysis of Chromium - - Samples were collected side-by-side in
the field in order to evaluate and compare the two NIOSH
monitoring methods for chromium. For the P & CAM #173 procedure,
nitric acid was used to dissolve the metals and ash the organic
matrix. The analysis was subsequently done by Atomic Absorption
using a range of standardized solutions for calibration. The
lower limit of detection by this method is reportedly 1.0
microgram of chromium. Limited analysis of spiked filters
showed a recovery efficiency of 110%.

36


The chemicals are primarily licensed for use by treatment plants
through the major manufacturers. The use of arsenical mixtures
has become more cost competitive in recent years as a result of
rapidly escalating costs for solvents and oils used with PCP

and creosote. In addition, CCA has a distinct advantage of not
requiring solution heating for treating thus resulting in some
energy cost reductions. These advantages are offset somewhat by
the requirement for more complete drying of the wood prior to
pressure treatment. In contrast, ACA treatment is done at elevated
temperatures and does permit some pre-conditioning of the wood in
the pressure cylinder.

CHROMATED COPPER ARSENATE --

This mixture is the most commonly utilized material for pressurized
water-base treatment at ambient temperature. There are three
types of CCA -- Type A, B, and C -- already described in Table III
which differ only in percentage composition of the three basic
elements. All contain hexavalent chromium, bivalent copper, and
pentavalent arsenic. Type A CCA solution, which has limited
commercial use, is either mixed at the treatment plant by blending
dry potassium chromate and copper sulfate with arsenic acid, or

it is purchased as a 60% concentrate. Type B is supplied in

paste form and is diluted on site to the concentration required.
Type C, which accounts for most of the CCA used commercially, is
supplied to treating plants as a 50% solution concentrate (Report
of USDA-States-EPA Preservative Chemicals RPAR Assessment Team).
It is licensed for use by Osmose Wood Preserving Company and
Koppers Company, Inc.

The total usage of these mixtures during 1979 was Type A-5, 178,000
pounds; Type B-2,632,000 pounds; and Type C-25,954,000 pounds

(AWPA Wood Preservation Statistics, 1979). CCA is used for the
full cell treatment of marine piling in empty cell treatment of
poles, crossarms, fence posts, lumber, and timbers.

AMMONIACAL COPPER ARSENATE ~~

ACA is an ammoniacal solution of bivalent copper and pentavalent
arsenic licensed by the J. H. Baxter Co. The quantity of the
ammonia in any given volume of solution ranges from 1.5 to 2.0
times the weight of copper, expressed as copper oxide. This
treating solution is formulated at the plant site or the single
manufacturing facility located in Utah (Report of USDA-States-
EPA Preservative Chemicals RPAR Assessment Team). ACA is used
for the treatment of lumber and timber accounted for 1,065,000
pounds in 1979 (AWPA Wood Preservation Statistics, 1979).

15


CREOSOTE AND SOLUTIONS OF CREOSOTE

Creosote remains the primary wood preservative used in the United
States. It is defined by the industry today as a distillation
product of coal tar produced by the high-temperature carbonization
of bituminous coal. It has a boiling range of 390°F to
approximately 750°F. Other quality control specifications such

as specific gravity, water content, etc. have been established by
the industry. It is composed principally of higher molecular
weight aromatic hydrocarbons in addition to tar acids and bases.
(American Wood-Preservers' Association, 1978a). This preservative
has 200 or more identified components, but less than 20 are present
in amounts exceeding 1%. It is estimated that 10,000 or more
compounds are present in creosote. Compositions vary with batch
lots, depending on the coal source and production conditions. The
major components of typical samples are phenanthrene (21%),
fluorene and fluoranthene (each 10%) and, acenaphthene and pyrene
(each about 9%) (Lorenz and Gjovik, 1972).

Creosote is used directly or in combination with coal tar or
petroleum oil. Commonly, it is mixed with a "topped" coal tar

to increase the heavy aromatic content and toxicity to soil or
marine organisms in addition to other physical or chemical
properties desired for wood treatment (Hunt and Garrett, 1967).
Topped coal tar has had the light boiling fraction removed by
distillation. The percentage of "topped" coal tar used varies
from 20-50% of the final product blend. Higher costs of petroleum
and related products in more recent years have affected blends of
creosote/coal tar or petroleum solutions are blended to meet the
AWPA specifications (P2-68 and P4-70). It can be done at the
treatment plant, but typically is purchased premixed.

The most recent published statistics (1979) on the usage of
ereosote mixtures for wood preservation indicate that 98,751,000
gallons were applied per annum. (AWPA Wood Perservations
Statistics, 1979). Creosote produced at 24 plant sites located
primarily east of the Mississippi River. As shown in the

listing below, most are affiliated with chemical or steel companies
(Fuller et al, 1977).

Creosote Producers in the United States, 1972 --
Allied Chemicals Corporation
Detroit, Michigan

Ensely, Alabama
Ironton, Ohio

10


ACKNOWLEDGEMENTS

This project could not have been accomplished without the
assistance of the NIOSH Project Officer, James L. Oser, and

his staff. The laboratory analysis was performed by Environmental
Analysis Laboratories, Richmond, California, and Battelle
Laboratories, Columbus, Ohio.

The companies and trade associations within the wood preservative
industry cooperated extensively with this project. In addition
to the investigative team, substantial contributions were made

by Loren Dorman, AWPI, Don Rapp, Dow Chemical, and Charles
Flickinger, Koppers Company.

The funding for this work was provided by the Division of Cancer
Cause and Prevention, National Cancer Institute through the
Interagency Agreement in Research on Occupational Carcinogenesis
(Y¥-01-CP-60605).

vii


Table 14. Wood Treatment Plants - Comprehensive Phase
PLANT cc JI KK MM
PRESSURE
TREATMENT NON-PRESSURE NON-PRESSURE
PROCESS (THERMAL) PRESSURE (THERMAL) PRESSURE
Wood o PCP Type A o Creosote/ o CCA Type C o PCP Cellon Process
Preservative Petroleum o PCP Type A o PCP Type A
Oil; 30/70 o Creosote o Creosote
50/50 o ACA
o CCA Type C o Dual Treatment
(ACA, Creosote)
Treated o Poles o Railroad o Dimensional o Poles
Products Ties Lumber o Pilings
o Bridge o Bridge o Light Standards
Timber Timbers o Dimensional
o Sign Base o Guard Rail Lumber
Material Posts
o Poles, Pilings
Age of Plant 61 Years 76 Years 8 Years ll Years
Tank or 1 12'x12'x102' 4 8'X155' 1 8'x40' 2 8'x93'
Cylinder 1 12'x12'x15" 1 6'X132' 2 8'x95' 1 8'x144'
Description 1 8'x105'
1 20'x20'
Worker Population
o Treater Operators 3 4 6 3)
o Others Helping 3-4 9 10 6

with Loading/
Unloading

65


In past occupational exposure studies conducted at wood
treatment plants, significant tasks of concern were typically
identified as the short intervals of exposures occurring when
opening pressure cylinders or emptying bags of PCP to make up
treating solutions. None of the data, though relatively

recent, describe possible contributions from skin contact. Some
reports discuss work practices and skin protection and historic
cases of skin problems, such as chloracne or photosensitization.

Some of the older operations cited in the literature utilized PCP
received in bags for preparing treating solutions. This now is
done only to a limited extent and primarily at plants with
infrequent or minimal use. PCP in bags is used at a few plants

to provide the additional poundage for one and two thousand blocks
for making up a specific strength treating solution based on the
volume of oil or solvent. Flaked material, now commonly available
delivered in bulk truck-lots at commercial operations, is conveyed
in essentially closed systems with appropriate dust collection,

to mix tanks for bulk solution blending.

ARSENICAL PRESERVATIVE COMPOUNDS

Arsenical compounds, which are now the third largest category of
wood preservatives in use in the United States, have only come
into prominence in recent years. This has resulted because of
their aesthetics and odor-free attributes for specific wood
products. Escalating costs for creosote and oil-borne materials
have also stimulated interest in the use of these types of
treatment chemicals. Both the trivalent and pentavalent forms
of arsenic are used in commercial mixing operations. Most, if
not all, the arsenic is in the pentavalent form when reacted
with the other components (EPA Position Document 2/3, 1981).

Two basic mixtures account for most of the waterborne chemical
wood preservation now done in the United States. They are
Chromated Copper Arsenate, Type C, and Ammoniacal Copper Arsenate.
In past decades, these mixtures were made on-site at the
treatment plants, using the basic oxides or acid compounds
available. Many of the materials were handled in bags or drums.
Currently, CCA is made almost exclusively for the treating
industry as concentrate solutions. Consequently, some of the
previous potential employee exposures to the arsenicals,
chromates, or copper compounds are no longer likely as the
materials are premixed. With the exception of ACA, the waterborne
treatment chemicals are always used at ambient temperature.
Therefore, airborne exposures are unlikely unless the process
results in aerosol formation.

20


Currently 98% of wood treating done commercially in the United
States is by the pressure process (Cirilli, 1978). All pressure
treatment processes are now conducted with basically similar
equipment and techniques. The wood to be treated is loaded onto
small rail cars (trams). These are connected in series to fit
the length of the cylinder. They are pushed into the cylinder
using locomotives, forklifts,or other vehicles depending upon
the size of the plant. The dimensions of the cylinder can vary
from 48-120 inches in diameter with total lengths of 24-180 feet
(AWPA Statistics, 1978). The cylinder is sealed via a pressure-
tight door, either manually (with bolts) or hydraulically,and
the treatment cycle is initiated. The total length of time for
treatment varies with the specific type of wood preservative
solution, process, end-product use, and other factors such as
wood moisture content. At the end of the cycle, the treating
solution is pumped to storage tanks for later re-use, the

door is opened,and a steel cable in the cylinder,which extends
the full length of the tram units,is hooked to the locomotive,
winch, or other power equipment which pulls the treated material
on tram cars from the cylinder. The tram cars are moved to a
transfer point and the wood is off-loaded and stacked for storage
and/or shipment. The length of time between withdrawal from the
cylinder and off-loading can vary from a few minutes to a day

or more.

Most of the wood products utilized for the pressure processes
must undergo some form of pretreatment to reduce moisture to a
predetermined percentage. This improves the service life of the
preservative chemicals and permits the wood to accept the treat-
ment solutions in sufficient concentration to meet performance
specifications (Hunt and Garrett, 1967).

Methods of pre-treatment currently in use include:

Air seasoning - conditioning of wood for waterborne arsenical
or creosote treating of railroad ties.

Kiln drying - heat treating of wood for the same uses as air
seasoning.

Steam and vacuum treating - steam conditioning followed by

a vacuum to remove the excess moisture. It is commonly used
for pretreating southern pine. It is also done during either
the creosote or PCP oilborne preservative systems.

Boultonizing - this method was developed in the late 1800's
and consists of heating wood under vacuum in creosote or other
oil solutions to just above 212°F. This permits a rapid
removal of water. It is commonly used prior to creosote or
pentachlorophenol heating of soft wood such as Douglas Fir

and other western pines.


METHODS OF SURVEY
IDENTIFICATION AND SELECTION OF FACILITIES FOR STUDY

The purpose of the field studies was to evaluate occupational
exposures to wood preservative chemicals used in both pressure
and non-pressure treatment facilities throughout the United
States. The initial major source of informational statistics
on wood treating plants, sizes, locations, types of treatment
chemicals in use, etc, came from the industry-wide surveys
conducted by the American Wood Preservers' Association (AWPA),
(Gill and Phelps, 1974; Ernst and Ernst, 1977). From these,
prospective plant sites were identified from the preliminary
survey phase of the study. The producers of the wood
preservatives were also identified and,initially, one
manufacturer of pentachlorophenol and one of creosote were
considered for field evaluations. The arsenical and other salt
solutions were assumed to be formulated at each treatment plant
site in this stage of planning.

INITIAL SELECTION OF TREATMENT FACILITIES

Of the 440 wood preserving operations delineated in the AWPA
sponsored industry surveys, 35 were chosen as possible sites
for preliminary industrial hygiene surveys. The selection
criteria considered included:

e treatment process (pressure vs. non-pressure)
e preservative chemicals in use

® nature of materials being treated
(poles, ties, lumber)

e size of operation
e geographical location

These plants were contacted by phone for further specific
information on number of treatment tanks or vessels, production
schedules, number of plant personnel, and other data which would
be useful in choosing the plants for field investigations.

An additional twenty-one companies were contacted throughtout
the preliminary phase of the study in order to identify a
sufficient cross-section of plants representative of the
processes, chemicals, and products common to the treatment
industry. This included plants, using atypical materials or
processes, which were deliberately contacted for information
and possible follow-up field work.

25


REFERENCES

American Wood Preserver's Association 1978a. "Glossary of Terms
Used in Wood Preservation." American Wood Preserver's
Association Standard M5-78.

American Petroleum Institute 1959. API Toxicological Review,
Copper Naphthenate, Second Edition. American Petroleum
Institute, New York.

American Wood Preservers Association 1978b. "Standards for
Waterborne Preservatives." American Wood Preservers Associa-
tion Standard P5-78.

American Wood Preservers Association. AWPA Book of Standards.
Washington, D.C. 1976.

American Wood Preservers Association. Wood Preservation
Statistics 1977. Proc. American Wood Preservers Association:
pp. 74. 1978.

Armstrong, R.W., E.R. Eichner, D.E. Klein, W.F. Barthel,
J.V. Barnett, V. Johnson, H. Bruce and I.E. Loveless 1969.
Pentachlorophenol poisoning in a nursery for newborne infants.
II Epidemiologic and toxicologic studies. J. Pediatrics
75 (2): 317-325.

Arsenault, R.D. and Committee P3. 1977. "Report of Committee P3
Organic Solvent Systems." Proceedings of the American Wood
Preservers Association 73, 38-39.

Baader, H.C.E.W. and J.J. Bauer, 1951. Industrial Toxication due
to pentachlorophenol. Ind. Med. Surg. 20 (6): 286-290.

Bingham, E. 1978. Occupational Exposure to Inorganic Arsenic.
Fed. Reg. 43 (88) 19584-19631

Boutwell, R.D. and Bosch, D.K. 1959. The tumor-promoting action
of phenol and related compounds for mouse skin. Cancer Res.
19: 413-424,

Bureau of Mines, 1976. Coke Producers in the United States in

1976. Bureau of Mines Mineral Industrial Surveys. United
States Department of the Interior, Washington, D.C.

87


Solvent Vapor drying - this process is carried out using
petroleum naphtha at elevated temperatures of 270-350°F. The
vaporizing of the naphtha extracts the moisture from the wood
which is later separated by distillation. A vacuum is applied
to remove excess naphtha and additional wood sap and water.
Although in limited commercial use, when used it is usually
associated with creosote treatment of crossties and timbers
for the railroad industry (Fuller, et al 1977).

The full-cell treatment process is only used with the aqueous
preservative chemicals and creosote when maximum preservative
retention is required, such as for marine pilings, timbers, and
associated uses. The empty cell processes control the quantity
of preservative retained in the wood and provide a better pene-
tration depth with a cleaner surface (Fuller, et al 1977).

More recently developed pressure treatment methods utilize volatile
solvent-carriers. The CellonR process is done with liquified
petroleum gas (LPG) extraction followed by pressure application

of PCP in Diisopropyl ether. The DowR process uses methylene
chloride as the solvent-carrier for pentachlorophenol. Both
provide a cleaner non-oily surface lighter in color and more
aesthetically acceptable.

NON-PRESSURE TREATMENT

Several types of non-pressure processes have been used to treat
wood. These include: 1. brushing and spraying of woods which
are typically already a part of a structure; 2. atmospheric
Pressure immersion processes, such as dipping, steeping, cold
soaking, and thermal (hot and cold) and diffusion methods;

3. vacuum process (Hunt and Garrett, 1967). Some of these, such
as the spraying and dipping processes for sap stain control with
the sodium salt of PCP, were only meant to be temporary surface
treatments.

Brushing and spraying were typically done with creosote, either
heated or cold. Preservative chemicals in a paste form can also
be brush applied. The latter was widely used for groundline
treatment of poles or posts on site (Hunt and Garrett, 1967).

The thermal process is the only remaining commercial non-pressure
method still in use. Pentachlorophenol in a light petroleum oil

(kerosene boiling fraction) is the major preservative. Creosote

has been used in the past, but now is limited to a single plant.

The non-pressure treatment vessel can be a square or rectangular

tank used for butt or full-length treatment of poles, or a fifty-
five gallon drum or series of drums for treating fenceposts (Hunt
and Garrett, 1967).

The vessel is loaded with the wood products and weights are placed
on top of those materials receiving reaming full-length treatment
to keep them submerged.


e Wipe sample analyses of residual salts present on the
surface of dry ACA and CCA treated wood indicated
possible skin contamination problems if the treated wood
is handled directly without appropriate water impervious
gloves.

CRITERIA FOR THE COMPREHENSIVE SURVEY PHASE

Based on the data and sampling methods developed in the
preliminary survey phase, the monitoring parameters and
limitations of prospective comprehensive surveys were defined.
Candidate plant sites based on size, process method, and
geographical distribution were tentatively identified for
telephone contact and follow-up discussion. The analytical
methods evaluated indicated sufficient sensitivity for
personal sampling to monitor treatment chemical exposures even
during short-term tasks, such as cylinder door opening which
occurs for periods of approximately 15-30 minutes, once or more
during the work shift.

The plants contacted represented the complete spectrum of
process methods, products treated, and age of facilities.
Additional attempts were made to include those processes which
are conducted only at a limited number of United States plants
such as PCP treatment by the Cellon and Dow processes and dual
treatment of marine piling with arsenicals and creosote.

Plants selected were primarily those which use more than one
treatment chemical. They were chosen on the basis of the
number of personnel potentially exposed so that sufficient

air sampling could be conducted in a reasonable time period to
provide an indication of health risk. Sampling was subdivided
by job classification, task performed, treatment material
utilized, and processing method. Work practices, engineering
and other factors affecting exposure were also to be evaluated
in more detail.

Time-weighted average (TWA) full shift sampling was done where
possible. This was limited, however, to plants or job
classifications where only single treatment chemical is in use
throughout the shift. In all instances, short-term sampling was
planned for the critical tasks such as opening and recharging
the cylinders and other tasks,both routine and unique, which
might result in significant peak exposures.

Sampling and Analytical Methods

Creosote--

The sampling and analytical procedure for creosote was to be

a modification of the NIOSH P & CAM 217 procedure for coal tar

pitch volatiles. The gravimetric determination of cyclohexane
extractables was to be followed with analysis by ultraviolet

61


Table 15.

PCP Non-Pressure Treatment Facility (Plant CC)
Employee Exposure Levels

Job Classification

Task Evaluated

Sampling Time

Air Concentrations

(Min. ) (ug/m*)
Treater Operator Filling butt dip tank 23 4.9
with hot PCP oil
Filling full-length 9 53.9
tank with hot PCP oil 17 275.0
Second Shift 470 13.0
Operations
Draining full-length 70 8.6
tank of PCP oil
Yardman Unloading full-length 162 15.2
tank 118 80.4
117 43.
Pole Inspector Inspection and
Quality Control Assay 14 170.1

67


Creosote solutions are usually applied alone. However, they may
be used as part of a dual treatment system where specific
additional preservative properties are needed. In a few
geographical locations including the Gulf Coast and southern
California areas, salt water piling requires dual treatment to
prevent damage by crustacean borers. An arsenical treatment,
either CCA or ACA with complete air drying, is followed by a
second pressure treatment with creosote. Mixtures of creosote
and other preservatives have been used in the past, but are not
currently used in commercial operations. Creosote containing 2%
PCP has increased toxicity to soil and marine organisms, and
creates corrosion problems with treating equipment. As a result,
its use is very limited (Fuller, et al, 1977).

PENTACHLOROPHENOL (PCP)

Pentachlorophenol is the second most commonly used wood preserva-
tive in the United States today. The latest figures available
indicate that 39,730,000 pounds of dry PCP were used in 1979
(AWPA Wood Preservation Statistics). This does not include the
sodium salt form used for dip and spray applications to green
lumber. It is used primarily as a 5% solution in petroleum
solvent carriers to treat poles, crossarms, lumber, timbers,
fence posts, and other applications where a clean paintable
surface is not required. The petroleum carriers most commonly
used for these purposes are the P-9 Type A or Type C oils. Type
A is a light oil similar to diesel fuel. Type C solvent is a
petroleum fraction with a boiling range comparable to mineral
spirits (Fuller et al, 1977).

Treating is usually done with 5% PCP solutions; however, a few
plants use higher concentrations to reduce solvent consumption
which has no preservative value per se. In a few specialized
applications, a wax water-repellent is added with PCP in a
solvent carrier, such as Type C oil.

Recent use of PCP with more volatile solvents, which quickly
evaporate from the wood after impregnation, gives a cleaner, less
colored, and paintable treated surface. The most common of these
is a combination of LPG and ether licensed by the Koppers Company
as the Cellon process. Another volatile solvent system P-9

Type D uses methylene chloride by the Dow process. Both of these
processes, while providing excellent results for ground contact
applications uses, presently account for only a very small
fraction of the total PCP treatment done in this country

(Fuller, et al, 1977).

Only three companies manufacture PCP at the present time in the
United States. They are Dow, Reichhold, and Vulcan Chemical.
PCP is produced in flake form or as 1,000- and 2,000-pound
(cylinder shaped) blocks. Some commercial sources also supply
PCP already dissolved in oil solutions delivered by tank truck
to treating plants.

12


In commercial wood treatment plants, the distillate material can
be used solely but, in most treating operations, creosote is
blended with coal tar, tar bottoms, and/or heavy oils; these may
be of coal or petroleum origin. Although all are referred to as
creosote, there are significant compositional variations between
plants. The coal utilized in the coking process can also affect
both the composition of the coal tar and creosote derived. No
specific details are available through the literature or industry
sources.

There is a substantial body of compositional and general
information available on creosote distillates and commercial
blends used in wood treatment processes (Lorenz and Gjovik, 1972
as cited in EPA PD-2/3, 1981). It is known that they contain
some of the aromatic amines and nitrogen compounds of occupational
concern for latent health effects, such as skin, lung, or bladder
carcinomas. Sulfur compounds are also present, but little data
is available on concentrations in creosote. These have been
shown by some investigations to act as accelerators or promoters
of the carcinogenic process in laboratory animal studies (Horton,
1961; Lijinsky, 1957).

Data on the composition and distribution of aromatic and

polynuclear hydrocarbons indicates a significant percentage of

the 3 to 5-ring fused compounds (Lorenz and Gjovik, 1972; Combes,
1954). While many have been specifically identified, there is a
paucity of quantitative data on the two most potent carcinogens

of these chemical groups; i.e., benz (a) pyrene and dibenzanthracene.

The variety of blended materials used for creosote treating
would realistically preclude quantifying the range of these
specific known carcinogenic compounds in the commercial mixtures.
More importantly, this type of specific PNA analysis in the past
has not provided a reliable index of potential skin contact or
inhalation hazard than total benzene extractable organics

because individual compounds in the creosote mixtures, independ-
ently or in combination, can act as carcinogens directly, or as
accelerators, promoters, and carcinogenic inhibitors.

Direct skin contact with creosote, if not properly removed,
results in chemical skin burns (NIOSH, 1977a). The Pesticide
Exposure Response System of EPA contains a number of reports of
skin erythema and frequent chemical burns in personnel handling
creosote-treated wood products. Skin burns and allergic reactions
from creosote contact have also been reported in a survey of the
accident history of fifty pressure treating plants (Johnson, 1978a
and McMillian 1976).

While it can be scientifically argued that the wood preservative
solutions are not identical to the airborne mixtures present in
the coking oven industry, specific biological or other data have
not been presented indicating that more liberal occupational
limits are justified.

17


which produce a variety of wood products handle most of the
preparation on-site; i.e., peeling, incising, cutting to
dimension, shaping, framing, etc. Others purchase or receive
from customers only peeled logs or pre-cut materials which they
further process to the desired end-product specifications.

Plants often handle TSO requests - Treatment Surface Only -
meaning that no cutting or other processing is needed and the
wood is ready for treatment. The nature of the wood processing
done is determined by end-product use and customer specifications.
Poles and heavy bridge structure are typically full-length
incised to increase the rate and quantity of pentachlorophenol

or creosote penetration, particularly when these materials are
treated green. Some customers require that railroad ties be

air dried to industry specifications prior to creosote treatment,
while others accept or specify pre-treatment by boultonizing or
vapor drying followed by creosote pressure treatment. The framing
specifications for utility or power poles will vary by company
requirements and geographical location.

The transfer and handling of untreated and treated wood are
almost exclusively done with forklift or front-end loader
vehicles. In some instances, usually at the smaller plants,
limited manual handling may occur. Plants that utilize tram
cars with rounded side frames often place additional pieces
around bound bundles of dimensional lumber to fill the cars to
capacity. During unloading of the treated wood, these separate
pieces must be removed by hand. It is generally done by the
yard crew employees rather than treater operators.

All wood products treated in pressure cylinders are bound with
chain or metal straps to keep the material from floating off
the tram car when the cylinder is flooded with preservative
solution. This minimizes the likelihood of materials becoming
misaligned and jamming the cylinder when the tram cars are
withdrawn at the end of the treatment cycle. In spite of
precautions, a chain or strap will occasionally break which
may or may not cause problems during unloading. Poles tend to
be more likely to misalign in cylinders than dimension lumber
and shorter length products.

Cylinder loading and unloading operations vary considerably

in sophistication and effectiveness. Forklift vehicles or
locomotives are typically used to push or pull the tram cars
into or out of the cylinder. Some tram cars have wheels while
others have only a slotted metal frame which slide along the
track. Bridge rails between the cylinder and track end in
front of the cylinder are placed and removed manually. Others
are designed to be hydraulically operated in conjunction with
the cylinder door.

Most treatment facilities surveyed during the preliminary study

phase had dual tracks for switching loads of treated and
untreated wood. This reduces the time of door openings and

46


REFERENCES

Rapp, D.E. Industrial hygiene study: Pentachlorophenol users
plants. Industrial Hygiene Laboratory, Health and Environ-
mental Research, Dow Chemical U.S.A., Midland, Michigan 48640,
13 pp. 1978.

Robson, A.M., J.M. Kissane, N.H. Elvick and L. Pundavela, 1969.
Pentachlorophenol poisoning in a nursery for newborn infants,
I. Clinical features and treatments. J. Pediatrics 85(2):
309-316.

Rose, A. and E. Rose 1961. The Condensed Chemical Dictionary,
Sixth Edition, Reinhold, New York.

Rosenberg, M.J., Landrigan, P.J. and Ss. Crowley. "Low-level
Arsenic Exposure in Wood Processing Plants", American
Journal of Industrial Medicine 1: 99-107 (1980)

Saffiotti, V. and P. Shubik. 1963. Studies on promoting action
in skin carcinogenesis. Nat. Cancer Inst. Monogr. 10: 489-507

Schwetz, B.A., J.M. Norris, G.L. Sparschu, V.K. Rowe, R.J. Gehring,
J.L. Emerson and C.G. Gerbig. 1973. Toxicology of chlorinated
dibenzo-p-dioxins. Environ. Health Perspect. 5: 87-99.

Schwetz, B.A., P.A. Keeler and P.J. Gehring, 1974a. Effect of
purified and commercial grade tetrachlorophenol on rat
embryonal and fetal development. Toxicol. Appl. Pharmacol. 28:
146-150.

Schwetz, B.A., P.A. Keeler and P.J. Gehring. 1974b. The effect
of purified and commercial grade pentachlorophenol on rat
embryonal and fetal development. Toxicol. Appl. Pharmacol. 28:
151-161.

Shambaugh, P. Tar Cancer of the lip in fisherman. J. of the Amer.
Med. Assoc., 104: 2326-2329: 1935.

Sirover, M.A. and L.A. Loeb, 1976. Infidelity of DNA synthesis in
vitro: Screening for potential metal mutagens or carcinogens.
Science 194 (4272): 1434-1436.

Thompson, W.S. 1975. Status of Pollution Control in the Wood

Preserving Industry in 1974. Proceedings of the American Wood
Preservers' Association, 71: 97-104.

91


FIELD SURVEY PROCEDURES

Area air samples were taken at sites of potential exposure, such
as adjacent to the treatment vessel equipment or the treated
wood -- in order to evaluate different air sampling methods,
define analytical limitations,and obtain an index of exposures
possible during critical short-term tasks. Air monitoring for
creosote, pentachlorophenol, copper, chromium, and arsenic was
done during the preliminary plant site visits. Ina few
instances, wipe (touch) samples were taken to evaluate the
presence of residual salts on the surface of the wood to determine
if skin contamination problems were likely from handling freshly
treated or dried wood. Bulk samples of creosote solutions were
taken at each plant where it was air monitored for preparation
of analytical standards.

SURVEY EQUIPMENT AND CALIBRATION

Air sampling was conducted with portable, battery-operated
Bendix BDX-41, C-115s or MSA Model S air sampling pumps. The
pump flow rate through the sampling trains were determined with
a Universal Pump Calibrator, Model 301 before and after each
field survey. Pre- and post-flow rates were averaged for the
air volume calculations. Precision rotometers were used in the
field to check calibration before and after the sampling period.

General area sampling was done at sites of probable exposure
adjacent or downwind of operating equipment and where maximum
peak concentrations were anticipated to occur during short-term
tasks. In most instances, the samples were taken in the latter
locations; i. e. adjacent to cylinder doors during opening,to
assure that a sufficient quantity of material was collected for
analytical purposes and to permit method comparisons where
more than one was being evaluated.

AIR SAMPLING METHODOLOGY
Pentachlorophenol --

The NIOSH recommended midget bubbler sampling method (S-297) and
a silica gel adsorption tube procedure developed by Dow Chemical
were used for monitoring airborne pentachlorophenol. Side-by-side
areas samples were collected using both methods in order to
compare them for sensitivity and reproducibility. The sampling
train for the NIOSH method included a 0.8 micron mixed cellulose
acetate (MCE) prefilter supported by a stainless steel screen in
a three-piece cassette connected in series with a midget bubbler
containing 15 milliliter of ethylene glycol. This was followed
by a second empty midget bubbler used as a trap to protect the
sampling pump from solvent losses. At the completion of sampling,
the prefilter was removed from the cassette and added to the
ethylene glycol solution to preclude sublimation of any airborne
pentachlorophenol collected.

29


At larger plants,the block PCP is typically dissolved in oil or
solvent in the treating cylinder or tank, diluted to the final use
concentration,and then pumped to storage. Automated feed hopper
silo systems are available for flaked PCP. It is fed from bulk
storage mechanically to the mix tank, oil is added ,and the

mixture heated to dissolve the PCP. After Quality Control checks,
it is pumped to storage for use as needed. Manual dumping and
mixing of flake PCP from bags only occurs at smaller treatment
operations or for limited additions to solutions to bring PCP
concentration up to the required minimum strength.

Commercial PCP manufacturing results in the formation of

secondary reaction contaminants such as the tri- and tetra-
chlorophenol isomers, chlorinated dibenzodioxins, dibenzofurans,
and phenoxyphenols. To a lesser extent,this is also true of the
Dow Chemical, Dowicide EC-7. This has been specifically processed
to remove most of the side reaction dioxin compounds of environ-
mental and occupational concern. Compositional data on PCP and
the Dowicide EC-7 are shown below in Table 2.

Table 2. Comparison of composition of commercial grade
and purified grade Pentachlorophenol (PCP)

Analytical Results

Component Commercial? Purified?
(Dowicide 7) (Dowicide EC-7)
Pentachlorophenol 88.4% 89.8%
Tetrachlorophenol 4.4% 10.1%
Trichlorophenol 0.1% 0.1%
Chlorinated phenoxyphenols a
Octachlorodioxins 2500 ppm 15.0 ppm
Heptachlorodioxins 125 ppm 6.5 ppm
Hexachlorodioxins 4 ppm 1.0 ppm
Octachlorodibenzofurans 80 ppm 1.0 ppm
Heptachlorodibenzofurans 80 ppm 1.8 ppm
Hexachlorodibenzofurans 30 ppm 1.0 ppm

aSample 9522 A
Technical grade PCP reduced by distillation

Source: Johnson, 1978c.

Because of increased costs for the PCP distillation, and the
disposal of hazardous by-products and the lack of consumer
acceptance,Dow Chemical has discontinued the manufacturing of
the EC-7 product line.

13


A voluntary annual medical examination program is also conducted
at this plant. No specific medical tests are included. A local
physician, medical clinic, or hospital generally handle emergency
services and accident cases. In some cases, there are employees
trained in first-aid at the plant.

Informal joint management-employee safety meetings are conducted
periodically to review problems or questions dealing with safety
experience, specific hazards, or operating procedures. New
employees typically receive an informal training session on
safety and technical aspects of their job or work areas.

No industrial hygiene monitoring has been conducted at any of
these plants either by insurance carriers or regulatory agencies.

Air Sampling Results --

Area air samples were taken in control buildings, adjacent to
treating tanks, or at other locations downwind of the process to
permit collection of sufficient material for evaluating alternate
sampling and analytical methods. With the exception of the
control room, the samples represent maximum potential short-term
peak exposures which a treating operator or yard worker might
experience when working in close proximity to the airborne
sources. The monitoring results are summarized by location and
treatment chemicals in Tables 12 and 13.

Table 12 Airborne Concentrations of Pentachlorophenol
TLV 0.5 mg/m?
Air Concentrations (mg/m?)

Treatment NIOSH DOW
Sample Location Plant S-297 Silica gel
Vacuum chamber E 0.25 <0.09+
door opening
Control building E 0.13 <0.09+
adjacent vacuum pump
Pump Room (7 0.34 <0.34+
(below ground level)
Top of Treating Tank Cc 0.36 1.33+
lid Cc 0.13 <0.27%
Adjacent treating. tank B 0.04 0.13+
prior to unloading B 0.10 0.13t

tprefilter analyzed by NIOSH Method 8-297
*no prefilter was utilized

57




REFERENCES

Goldstein, J.A., M. Friesen, R.E. Linder, P. Hickman, J.R. Haas
and H. Bergman 1977. Effects of pentachlorophenol on hepatic
drug-metabolizing enzymes and porphyria related to contamination
with chlorinated dibenzo-p-dioxins and dibenzofurans. Biochem.
Pharmacol. 26: 1549-1557.

Gordon, D. 1956. How dangerous is pentachlorophenol? Med. J.
Australia 2: 485-488.

Hinkle, D.K. 1973. Fetotoxic effects of pentachlorophenol in the
Golden Syrian Hamster. Toxicol. Appl. Pharmacol. 25 (3): 455.

Horton, W.A. An Investigation of the Carcinogenic Properties of
Various Coal Tars of Commercial Fractions Thereof. Report to
The Kettering Laboratory, Department of Preventive Medicine
and Industrial Health. Cincinnati: University of Cincinnati,
32 pages. 1961.

Hung, George M. and Garratt, George A. 1967. Wood Preservation
3rd Ed. McGraw Hill Book Company, New York

Hunter, D., 1955. Disease of Occupation. Boston. Little, Brown
and Co. pp. 373-377.

Johnson, E. L. 1978a. Notice of rebuttable presumption against
registration of pesticide products containing coal tar,
creosote and coal tar neutral oil. Fed. Reg. 43 (202)

48154 - 48266.

Johnson, E. L. 1978b. Notice of rebuttable presumption against
registration and continued registration of pesticide products
containing inorganic arsenic. Fed. Reg. 43 (202) 48267

Johnson, E. L. 1978c. Notice of rebuttable presumption against
registration and continued registration of pesticide products
containing pentachlorophenol. Fed. Reg. 43: 48443 - 48617.

Johnson, F.A., and R.B. Stonebill, 1961. Chemical pneumonitis
from inhalation of zinc chloride. Dis. Chest 40: 619-624.

Key, M.M., A.F. Henschel, J. Butler, R.N. Ligo and I.R. Tabershaw,

eds. 1977 Occupational diseases. A guide to their recognition
DHEW (NIOSH) Publication No. 77-181.

89


Additionally, the laboratory initially utilized a soxhlet
extraction procedure rather than the ultrasonics method.
Aluminum weighing boats were also later identified in use
rather than the required teflon containers. The latter two
discrepancies in the analytical procedure could account for at
least part of the apparent inaccuracy of the method. They
could not, however, explain the highly variable blank values
observed.

Repeat analysis of additional one milliliter aliquots of

stored sample extracts showed non-reproducible results from
samples and blanks as follows:

Coal Tar Pitch Volatiles (ug/filter)

Initial
Sample Extract Re-Analysis of Additional Extracts
1 25 160 215
2 140 265 295
3) 30 120 160
4 155 260 305
5 15 150 160
6 50 160 200
Blank 60 185 200

Correction for the blank values showed four negative sample
results when the replicate values were averaged. To further
evaluate the sensitivity and validity of the NIOSH (CTPV)
gravimetric procedure for creosote, spiked samples were
prepared covering a range of 20 to 200 micrograms per filter.
The silver membrane and the glass fiber filters used were
pre-extracted with cyclohexane to remove any oil, fiber,or
other residues that might interfere with the gravimetric assay.

The eight prepared samples sent to the laboratory gave the
following results:

Results of Spiked Creosote Filters

yg cyclohexane extractable material

Sample Spiked Amount Gravimetric Assay
1 100 55
2 200 50
3 Blank 50
4 25 80
5 200 20
6 Blank 95
7 100 70
8 25 20

34


The hexavalent chromium collected by the P & CAM #169 method was
analyzed by washing the filter with an acidic diphenylcarbazide
solution and measuring the resulting color reaction by spectro-
photometry at a wavelength of 540 nm. A set of standard solutions
was used to provide an absorbance calibration curve. The lower
limit of detection by this method was 0.1 microgram hexavalent
chrome per filter with a recovery of 95%.

The sensitivity of the hexavalent chromium method is ten times
greater than the procedure for total chromium. The latter
method also allows for the analysis of two to three different
trace metals in one sample which are needed for ACA and CCA
process monitoring. This permits personal exposure sampling
without additional sampling equipment or undue burden on the
employee. The preliminary field survey data indicated that a
minimum of 20 minutes sampling would be needed to quantify and
evaluate critical exposures and tasks of concern such as
cylinder opening and unloading. 5

Analysis of Arsenic and Copper (NIOSH P & CAM #173) --

Filter samples were dissolved with nitric acid and the solution
analyzed by atomic absorption spectroscopy. A calibration curve
was prepared for each metal, plotting absorption vs concentration.
The detection limit and recovery rate for each were: arsenic

0.2 microgram/filter, with 105% recovery; copper 0.5 microgram/
filter, with recovery of 102%. Wipe/touch samples collected on
Whatman filters were also analyzed by the NIOSH P & CAM 173
method.

37