ASSESSMENT OF ARSENICAL PESTICIDE PLANTS
TO DETERMINE SOURCES, LEVELS AND
CONTROL TECHNOLOGY. £OR
POTENTIAL ARSENIC EMISSIONS
Draft Final Report
GCA/TECHNOLOGY DIVISION

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950R75060
GCA-TR-75-20-G
Prepared for
U.S. ENVIRONMENTAL PROTECTION AGENCY
Research Triangle Park, North Carolina
Contract No. 68-02-1337
Task Order No. 9
EPA Project Officer
J. S. Cooper
*
July 1975
ASSESSMENT 0? ARSENICAL PESTICIDE PLANTS
TO DETERMINE SOURCES, LEVELS AND
CONTROL TECHNOLOGY. 3j$R.
POTENTIAL ARSENIC-MISSIONS
Draft Final Report
by
Mark I. Bornstein
_ . ,	.	Property of U.S. Environmen a
Project Director
protection Agency Library MD-108
Norman P. Surprenant
AUG 2 31983
1200 Sixth Avenue/Seattle, WA 98101
GCA CORPORATION
GCA/TECHNOLOGY DIVISION
Bedford, Massachusetts
U.S. EPA LIBRARY REGION 10 MATERIALS
RXDD
0050S1

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ABSTRACT
This report is a study of arsenic air emissions resulting from the
manufacture of 25 pesticides. The arsenical pesticide industry is
characterized with respect to size, production, trends, control equip-
ment, usage, and the potential for fugitive air emissions. The emis-
sions resulting from the operations of the approximately 200 formula-
tors who manufacture end products from the basic arsenical compounds
are not considered in this report.
ii
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CONTENTS
Page
Abstract	ii
List of Figures	iv
List of Tables	v
Sections
I	SUMMARY	1
II	INTRODUCTION	2
III	PRODUCTION ESTIMATES OF PESTICIDES	5
IV	MANUFACTURING PROCESSES AND EMISSIONS	12
V	CONTROL EQUIPMENT	16
VI	ARSENICAL PESTICIDE DESCRIPTIONS	18
VII	REFERENCES	61
ill
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No.
1
2
3
4
5
6
7
8
9
10
11
12
FIGURES
Page
Major Inorganic Insecticides - Production	6
Production Estimate of Methanearsonic salts	8
Arsenic Trioxide	9
General Flow Diagram of a Pesticide Manufacturing Plant	14
Arsenic Acid Production	21
Flow Diagram for the Manufacturing of Arsenic Trioxide
From a Copper Smelter	31
Arsenic Trioxide Production	32
Process Flow Diagram for Manufacture of MSMA,	DSMA and
Cacodylic Acid	35
Flow Diagram for Production of Calcium Arsenate	41
Domestic Production of Calcium Arsenate	42
Flow Diagram for Production of Lead Arsenate	50
Lead Arsenate Production	51
GCA/TECHNOLOGY DIVISION QOA

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TABLES
No.	Page
1	Arsenical Compounds and Their Use	4
2	Production Statistics for MSMA, DSMA,	and Cacodylic Acid	7
3	Producers of Arsenical Pesticides	11
v
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SECTION I
SUMMARY
The pesticide industry is relatively small in production volume when com-
pared to other industries. The production volume was only about 1.3 bil-
lion pounds in 1973. Of this total a very small percentage (6 percent) is
attributed to the arsenical pesticide industry (75 million pounds).
Emissions resulting from the manufacture of arsenical pesticides are esti-
mated to be between 4 and 151 tons for the entire industry. The exact
figure is dependent upon the amount and type of control equipment used by
the industry, a factor which is not currently known.
Arsenical pesticides are being produced by approximately twenty-four firms
and it is believed that in almost all cases control equipment is already In
use. Therefore, the 151 tons of arsenic emissions is an upper limit. The
value of 151 tons emitted is still small-in comparison to emissions re-
sulting from the application of the pesticides (12,750 tons).
The arsenic emissions are generated from four major unit operations:
1.	Raw material handling equipment
2.	Reactor
3.	Product purification equipment
4.	Final Product packaging equipment
The types of control equipment suitable for these operations are baghouses
and scrubbers.
1
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SECTION II
INTRODUCTION
PURPOSE OF STUDY
Recently, a great deal of attention has been aimed at identifying and con-
trolling pollution associated with the manufacture of pesticides. Several
studies have been performed to characterize the wastewaters from this
1 2
industry, » but very little has been done to identify sources of air
pollution. The work summarized in this report represents an initial at-
tempt to identify and quantify arsenic air emissions associated from the
manufacturing of arsenical pesticides.
SCOPE OF WORK
The main objective of this study is to characterize the arsenical pesticide
industry with respect to size, production, trends, control equipment,
usage and, to evaluate the potential for fugitive air emissions. The air
emissions resulting from the operations of the approximately 200 formulators
who manufacture end products from the basic arsenical compounds are not
considered in this report.
The primary sources of information utilized to achieve the above program
objective were the published literature, and information obtained from
state air pollution personnel and representatives of the pesticide in-
dustry. Due to the limited scope of this study no independent sampling
studies or field visits were undertaken.
2
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In order to estimate arsenic emissions from pesticide manufacturing, cur-
rent data on production volumes is required. Unfortunately, very little
data is available. While the U.S. Traiff Commission publishes production
data for various chemicals, information on pesticide production is not
reported in a meaningful manner and production data is available for only
a very limited number of arsenic based pesticide compounds. The estimates
of production in this report for the remainder of the 25 arsenical com-
pounds (see Table 1) used as pesticides are based on conversations with
representatives of the pesticide industry and upon previously published
literature.
Estimates of fugitive emissions are based on the best available information.
Although it was necessary to generalize many of the manufacturing opera-
tions, it is felt that the overall estimate of arsenic emissions from the
manufacturing of arsenical pesticide is reliable.
3
GCA/TECHNOLOGY DIVISION ~

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Table 1. ARSENICAL COMPOUNDS AND THEIR USE
Compound
Use
0	- Arsanlllc acid (sodium arsanllace)
1	- Arsenic add (arsenic pentoxide, arsenic
oxide)
I - Arsenic disulfide (trl and penta)
1 - Arsenic iodide (arsenous iodide)
I - Arsenic pencafluoride
Feed additive
Cotton defoliant
Textile printing, tanners
paint pigment, medicinals
Antiseptic
Laboratory research
I - Arsenic thioarsenate
I - Arsenic tribromide (arsenous bromide)
I - Arsenic Trichloride (arsenous chloride,
arsenic butter)
I - Arsenic rrifluoride (arsenous fluoride)
I - Arsenic trioxide (arsenous oxide,
arsenous acid)
Scavenger
Medicinals
Herbicide
Laboratory research
Precursor in production of
other arsenical compounds
I - Arslne (arsenous hydride)
0	- Cacodylic acid (dimethylarsinic acid)
1	- Calcium arsenate
I - Calcium arsenlte
I - Copper arsenate
Semiconductor industry
Herbicide
Insecticide
Insecticide
Insecticide - wood pre-
servative
I - Copper arsenlte
0	- Fluor chrome arsenate phenol
1	- Lead arsenate
0 - Methanearsonic acid (mono- and
disodium salts) (MSMA and DSMA)
0 - Methanearsonic acid (calcium salt)
Insecticide
Wood preservative
Insecticide
Herbicide
Herbicide
0 - Methanearsonic acid (ammonium salts)
0	- Paris green (copper acetoarsenlte)
1	- Sodium arsenate
I - Sodium arsenlte (arsenous add,
sodium salt)
I - Zinc arsenate
Herbicide
Insecticide
Uood preservative
Herbicide
Tree debarking
Herbicide
Insecticide
0	- Organic
1	- Inorganic
4
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SECTION III
PRODUCTION ESTIMATES OF PESTICIDES
Pesticides are classified eithe'r on the basis of their chemical nature
(inorganic, organic, organophosphorous, etc.) of according to their use.
Table 1 is a listing of the 25 arsenical compounds studied and their
use. In recent years, inorganic compounds have been displaced by organic
pesticides. The inorganic pesticide industry currently only represents
approximately 5 percent (60 million pounds)of the total pesticide
industry's output (1,349 million pounds). Prior to 1940, the industry
had produced essentially only inorganic pesticides.
The U.S. production of organic pesticides and related products in 1973
amounted to 1,289 million pounds. This represents an 11.3 percent in-
crease over the reported 1972 figure of 1,158 million pounds.^ The U.S.
production of all inorganic pesticides for 1972 is estimated to be only
i
60 million pounds. The inorganic arsenical compounds are dominated
by chromated copper arsenate, lead arsenate and calcium arsenate. They
account for approximately 30 percent (18 million pounds) of total inor-
ganic sales. Production statistics for the past several years are
presented in Figure 1.^ Lead arsenate and calcium arsenate represent
essentially all of the inorganic insecticide market (8 million pounds).
Chromated copper arsenate represents only 0.7 percent (12 million
pounds - 1973) of the total wood preservative industry.
As shown in Figure 1, the use of arsenic as an insecticide has steadily
dropped. However, the use of chromated copper arsenate, a wood pre-
servative, has increased. The use of arsenic in the organic pesticide
5
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Figure
I—CHROMATED COPPER
ARSENATE
•4-LEAD ARSENATE
(ACID AND BASIC)
CALCIUM ARSENATE
COMMERCIAL OR 70 %
Co 3 CAs04](2)
J	I	1_
I960 1965 I97C
ACTUAL YEARS
1975 I960
1985
1990
Major inorganic insecticides - production

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industry for manufacturing MSMA, DSMA, and cacodylic acid has steadily
increased offsetting the losses from the inorganic industry (see
Figure 2). Estimates of their most recent production statistics are
presented in Table 2.
Table 2. PRODUCTION STATISTICS FOR MSMA, DSMA,
AND CACODYLIC ACID

Production,

Compound
million lb
Year
MSMA
36
19 746
DSMA
9
19746
Cacodylic acid
1.5
19737
ARSENIC CONSUMPTION
Because of the limited amount of data available for the production of
individual arsenical compounds, it is impossible to accuractely estimate
the total production of all arsenical pesticides. However, an important
indicator that can be used to determine the trends in the arsenical
pesticide industry is the amount of arsenic trioxide (white arsenic or
arsenic oxide) used in the production of other arsenical compounds.
Arsenic trioxide is produced commercially in the United States by only
one company. It is produced as a by-product from the smelting of copper.
A process diagram and related emissions from the production of arsenic
trioxide are presented in Section V.
The domestic production of arsenic trioxide for 1974 is estimated to be
g
13,000 tons. Imports of arsenic trioxide are estimated to be 11,000
tons. 5 Therefore, the total consumption of arsenic trioxide in 1974 is
estimated at 24,000 tons (see Figure 3). The main uses of arsenic tri-
oxide are for agricultural chemicals (70 percent), for glass manufactur-
ing (20 percent) and for industrial chemicals, and pharmaceuticals (10
7
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50
~

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EXPORTS
1940 1945 1950 1955
Figure 3.
IMPORTS

,,A*-production
	I	I	I	I	I	I	
I960 1965 1970 1975 1980 1985 1990
ACTUAL YEARS
Arsenic trioxide production

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percent). Based on the 70-percent agricultural use of arsenic trioxide,
25.5 million pounds of arsenic are used for pesticide manufacturing.
This figure is in close agreement with the estimated usage of arsenic
for the manufacturing of lead arsenate, calcium arsenate, chromated
copper arsenate, MSMA, DSMA, and Cacodylic acid. These six compounds
are the major users of arsenic with a combined total of 24 million
pounds; Therefore, the remaining 1.5 million pounds of arsenic are used
by the industry for the manufacturing of other miscellaneous compounds.
A listing of the manufacturers of arsenical compounds and their products
are shown in Table 3. This listing was obtained from the Stanford Re-
search Institute "Directory of Chemical Producers" (1975). No attempt
was made to confirm this information, but in conversations with several
of the companies, they stated that certain information was erroneous.
10
GCA/TECHNOLOGY DIVISION ©OA

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Table 3. PRODUCERS OF ARSENICAL PESTICIDES
O
O
>
n
n:
Z
o
5
9
g
<
C/}
o
z
Abbot Labs
Allied Chemical
American Smelting t Bafining
Anaal Chemical
Apacha Chemical
Blua Spruce Co.
Cheaper Chemical
Chevron
City Chemical
Diamond Shamrock
Dimensional Plgaenta
FMC
G.D. Searle Co.
Los Angelea Chenlcal
Halllnckrodt
Osmoro Wood Preserving
Pennvalt
Rohm and Haaa
Salisbury Labs
Triangle Chemical
Vlneland Chemical
U.A. Cleary
Uhlttaker Corp
Uoolfolk
:
a
a
« S
i x
u d
o o
9 W
as
2
I
*Ho longer baing produced

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SECTION IV
MANUFACTURING PROCESSES AND EMISSIONS
The manufacturing processes for pesticides vary considerably from product
to product. A generalized flow diagram that can be applied to all pesti-
cide manufacturers is shown in Figure 4. The major process operations
that have the potential of emitting arsenic emissions are the raw mate-
rial handling equipment, the reactor, the product purification equipment,
and the final product packaging equipment.
RAW MATERIAL HANDLING EQUIPMENT
Depending on the pesticide being produced, the arsenical raw materials
can be either in liquid form or in solid form. Emissions from the
handling of liquid raw materials are negligible. However, emissions
from handling of solid materials do exist. The usual method of handling
the raw material, which in most cases is arsenic trioxide, is by indi-
vidually opening and dumping the steel drums into either a temporary
storage bin or into the reactor. This method of handling necessitates
the emission of fugitive dust.
One company has recently reported emissions from the handling of arsenic
trioxide. Controlled emissions (with a 99.2 percent efficient scrubber)
are 31.5 pounds of arsenic per year. A controlled emission factor based
on an estimate of this firm's production capacity, results in 0.0064
pounds of arsenic being emitted for each ton of arsenic trioxide used.
If emissions from the handling of arsenic trioxide were not controlled,
total arsenic discharge from this firm would be approximately 2 tons
12
GCA/TECHNOLOGY DIVISION CPA

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per year from raw material handling. This results in an uncontrolled
emission factor of 0.8 pounds of arsenic per ton of arsenic trioxide
used.
Using the uncontrolled emission factor of 0.8 pounds and knowing the
national consumption of arsenic trioxide for agricultural pesticide
manufacturing 16,800 tons (70 percent of 24,000 tons), total uncontrolled
emissions from raw material handling is estimated to be 7 tons/year.
Assuming all manufacturing firms have control equipment, then controlled
arsenic emissions from raw material handling are less than 1 ton per
year from all firms.
REACTOR
Numerous types of reactor vessels are used by the industry. They may
range from a simple mixing tank to the more complicated pressurized re-
actor. Emissions from the reactor occur during charging of the reactor,
venting of the reactor and unloading of the reactor. Very little inform-
ation is available about the rate of emissions from these operations.
One firm, however, has reported uncontrolled emissions of 0.21 pounds
per day. Using this factor and the numb.er of firms manufacturing ar-
senical pesticides (24), total estimated arsenic emissions from reactors
are 1 ton per year.
PRODUCT PURIFICATION EQUIPMENT
The purification of the final product may involve many steps. Examples
of these processes are evaporators, grinding mills, dryers, and washers.
Only a limited amount of emissions data is available for these opera-
tions. Data has been reported for a spray dryer using a cyclone dust
collector. Controlled emissions (99.2 percent efficiency) are reported
13
GCA/TECHNOLOGY DIVISION OPA

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LIQUID
RAW
MATERIAL
(NEGLIGIBLE
LOSSES)
(7 TONS)
( )-EMISSIONS UNCONTROLLED
( 136 TONS)
FINAL PRODUCT
PACKAGING
EQUIPMENT
FINAL
PRODUCT
(7 TONS)
Figure 4. General flow diagram of a pesticide manufacturing plant

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as 91 pounds of arsenic per year. Based on this reported emission data,
an estimate of the controlled emissions for the entire industry is 1 ton
per year. If no controls are used, total industry emissions would be
136 tons per year.
FINAL PRODUCT PACKAGING EQUIPMENT
The packaging of the final product will also result in emissions of
arsenic compounds. It is assumed that the emission rate will be the
same as for the handling of the raw materials. This will result in
approximately 7 tons per year being emitted from the handling of the
final product if it is uncontrolled and less than 1 ton per year if it
is controlled.
Total emissions from all manufacturing operations producing arsenical
compounds, assuming the worst case, no control, are 151 tons of arsenic
per year. Emissions with complete control are 4 tons of arsenic per
year.
Overall, the environmental impact from arsenical pesticide manufacturing
(4 to 151 tons) appears to be small compared to emissions resulting from
the application of the pesticides (12,750 .tons). Many of the large pro-
ducers of pesticides have already installed control equipment so that
emissions in fact are lower than the estimated 151 tons per year.
The next section will describe the types of equipment available for the
control of arsenic emissions.
15
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SECTION V
CONTROL EQUIPMENT
Arsenical pollutants generated by the pesticide industry are essentially
in the form of dust. Because of the toxicity of the dusts used in the
manufacturing of pesticides, it is important that all sources of dust
be enclosed or tightly hooded to prevent escape of the material. These
sources should be ventilated to an air pollution control device.
Some of the sources emitting dust, which are mentioned in the previous
section, are not conducive to complete enclosure, and hoods should be
employed. Indraft velocities through openings in hoods around high
sources of emissions (grinding mills, raw material handling) should be
400 feet per minute or higher. Velocities through hood openings for
other operations, where dust is released with low velocity, should be
200 to 300 feet per minute.*®
The most common means of controlling emissions from the pesticide manu-
facturing industry are baghouses employing cotton sateen bags. Effi-
ciencies of 99.9 percent or better can be expected from this type of
control equipment.*®
In some applications, water scrubbers (of both the spray chamber and
the packed tower types) can be used to control dust emissions. Inertial
separators such as cyclones and mechanical centrifugal separators are
not recommended because collection efficiencies are not high enough to
prevent the smaller size particles from being emitted into the atmosphere.
16
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In the manufacturing of liquid pesticides, air pollution control prob-
lems usually entail collection of dusts in a wet airstream. For these
casesy baghouses cannot be used and wet scrubbers should be employed.
17
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SECTION VI
ARSENICAL PESTICIDE DESCRIPTIONS
This section describes the manufacturing processes for 25 arsenical
pesticides. Process descriptions for these manufacturing operations
are very limited and in several cases are not available. A brief de-
scription of the compound, its uses and past production data, if avail-
able, are presented with the process description.
18
GCA/TECHNOLOGY DIVISION C A.

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Arsanilic Acid
Synonyms:	Antoxylic acid, aminophenylarsine acid
Formula:	C, H. NH0 • As 0 (0H)_
04/	2
Properties: White, crystalline powder, practically odorless, soluble
in hot water, slightly soluble in cold water, alcohol,
and acetic acid; insoluble in acetone, benzene, chloro-
form, and ether.
Molecular
Weight:
Melting
Point:
217.0
232°C
Uses:
Starting point for the manufacture of arsenical medi-
cinal compounds; veterinary medicines.
Manufacturing
Process:
Arsanilic acid is produced by refluxing the products of
the reaction between arsenic acid and aniline. The
excess aniline is removed by steam distillation in the
presence of an alkaline solution (sodium hydroxide).
Finally, the sodium hydroxide solution is neutralized
with hydrochloric acid, causing the arsanilic acid to
precipitate out of solution.
Production
statistics:
No data available.
19
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Arsenic Acid
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Orthoarsenic acid, arsenic pentoxide
H3 As °4
White translucent crystals; soluble in water, alcohol,
alkali, glycerin
142
35.5°C
Boiling
Point:
160 C loses water
Uses:
Manufacture of other arsenical compounds, insecticides;
glass making; cotton defoliant
Manufacturing
Process:
Arsenic acid is produced by reacting nitric acid with
arsenic trioxide
As2°3
arsenic
trioxide
2H N03
nitric
acid
As2°5
arsenic
pentoxide
h2o
water
N2°3
nitrogen
trioxide
Production
Statistics:
Vs
arsenic
pentoxide
+ 3H20
water
2H. As 0.
3 4
arsenic
acid
A flow
diagram of the process is shown in Figure 5.
Farmers used 8 million pounds in 1965 and 6 million
pounds in 1971 as a cotton defoliant.
20
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FRESH
NITRIC
ACID
(POSSIBLE ARSENIC EMISSIONS)
N>
o
o
>
—I
rn
n
ZL
§
5
3
o
<
o?
O
z
NITRIC

ACID

STORAGE
TANK
hno3




(RAW MATERIAL
I LOSSES)
TRIOXIDE
VENT
5	jr
ARSENIC
ACIO
REACTOR
COUNTER CURRENT
WATER FLOW
MAKE-UP
WATER
PACKED
RASCHIG
RING
TOWER
WATER
STORAGE
TANK
N0X
SCRUBBER WATER
WATER USED IN
PROCESSING
RECOVERED NITRIC
ACID
FINAL PRODUCT
Figure 5. Arsenic acid production
~

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Arsenic Disulfide
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Boiling
Point:
Uses:
Manufacturing
Process:
Production
Statistics:
Arsenic bisulfide, arsenic monosulfide, ruby arsenic,
red arsenic glass, red arsenic sulfide, red arsenic
As2s2
Orange-red powder, soluble in acids and alkalies, in-
soluble in water
214
307°C
565°C
Leather industry, depilatory agent; paint pigments,
shot manufacture, pyrotechnics; rodenticide
Arsenic disulfide is manufactured by the roasting of
arsenopyrite and iron pyrites.
No data available
22
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Arsenic Iodide
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Manufacturing
Process:
Production
Statistics:
Arsenic triiodide, arsenous iodide, arsenious iodide
Orange-red shining crystalline scales or powder, un-
stable in sunlight or moisture, sublimes when heated
slowly, soluble in alcohol, ether, carbon disulfide,
chloroform and benzene; soluble in water with hydrolysis
455.7
146°C
Medicine, analytical chemistry
Direct union of arsenic and iodine.
No data available
23
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Arsenic Penta£luorlde
Synonym:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Boiling
Point:
Uses:
Manufacturing
Process:
Production
Statistics:
Arsenic fluoride
As ?5
Colorless gas
169.9
-80°C
-53°C
Analytical chemistry
Unknown
1974 less than 10 pounds
24
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Arsenic Thioarsenate
Synonyms:
Formula:
Properties:
Molecular
Weight:
Uses:
Production
Statistics:
None
As (As S4)
Dry, free-flowing yellow powder, stable; high-melting
Insoluble in water and organic solvents but soluble
in aqueous caustics.
278
Scavenger for certain oxidation catalysts and thermal
protectant for metal-bonded adhesives and coating
resins.
No data available
25
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Arsenic Tribromide
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Boiling
Point:
Uses:
Manufacturing
Process:
Production
Statistics:
Arsenic bromide, arsenious bromide, arsenous bromide
As Br^
Yellowish-white hygroscopic crystals; decomposed by
water
314.7
32.8°C
220°C
Analytical chemistry, medicine
Direct union of arsenic and bromine.
No data available
26
GCA/TECHNOLOGY DIVISION O A

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Arsenic Trichloride
Synonyms:
Arsenic chloride, arsenious chloride, arsenous chloride,
arsenic butter, caustic arsenic chloride, fuming liquid
arsenic.
Formula:	As Cl^
Properties: Colorless or pale yellow, oily liquid, soluble in con-
centrated hydrochloric acid and most organic liquids,
decomposed by water, fumes in moist air
Molecular
Weight:
181.3
Melting
Point:
-18°C
Boiling
Point:
130.5°C
Uses:
Intermediate for organic arsenicals (pharmaceuticals,
insecticides); ceramics
Manufacturing
Process:
By distillation of arsenic trioxide with concentrated
hydrochloric acid
^s2^3 +
6H CI
2As CI.
3H20
arsenic hydrochloric arsenic
trioxide acid	trichloride
water
Production
Statistics:
No data available
27
GCA/TECHNOLOGY DIVISION A

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Synonym:
Formula:
Properties:
Molecular
Weight:
Boiling
Point:
Uses:
Manufacturing
Process:
Production
Statistics:
Arsenic Trifluoride
Arsenic fluoride
As F3
Oily liquid
-5.9°C
57°C
Analytical chemistry
Unknown
1974 less than 100 pounds
28
GCA/TECHNOLOGY DIVISION ©@A

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Arsenic Trioxide
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Manufacturing
Process:
Arsenious acid, white arsenic, arsenious oxide, "arsenic,"
arsenous anhydride
4s2 Oj
White amorphous, odorless, tasteless powder; slightly
soluble in water, soluble in acids and alkalies; freely
soluble in glycerin
197.8
193°C (sublimes)
Manufacture of pigments, glass, shot and bullets; insec-
ticides; rat poison, feed additive, weed killer, hide
preservative, medicine, manufacture of other arsenic
compounds; ceramic enamels, aniline colors, mixed with
soda ash for boiler compounds, wood preservative
Arsenic trioxide is produced in the United States solely
as a by-product of a copper smelter at the Tacoma,
Washington plant of the American Smelting and Refining
Company.
The following is a description from the Encyclopedia of
Chemical Technology^ describing the manufacturing of
arsenic trioxide.
"Because arsenic trioxide is readily volatilized during
the smelting of copper and lead concentrates, it is.
concentrated with the flue dust. Crude flue dust may
contain up to 30% arsenic trioxide, the balance being
oxides of copper or lead, and perhaps of other metals
such as antimony and zinc. This crude flue dust is
further upgraded by mixing with a small amount of pyrite
or galena concentrate and roasting. The pyrite or galena
is added to prevent arsenites from forming during roast-
ing and to obtain a clinkered residue which can be re-
turned for additional processing. The gases and vapors
are passed through a cooling flue which consists of a
series of brick chambers or rooms called kitchens. The
temperature of the gas and vapor is controlled so that
they enter the first kitchen at 220°C and by the time
the gas and vapor reach the last kitchen they are cooled
29
GCA/TECHNOLOGY DIVISION ©©A

-------
to 100°C or less. The arsenic trioxide vapor which con-
denses in these chambers is of varying purity. The
condensed product is referred to as crude trioxide and
analyzes 90-95%. A higher-purity product is obtained by
resubliming the crude trioxide. The resubliming opera-
tion is normally carried out in a reverberatory furnace.
The vapors pass first through a settling chamber and
then through approximately 39 kitchens that cover a
length of about 225 ft. The temperature of the settling
chamber is kept at approximately 295°C, which is above
the condensation temperature of the trioxide. A black,
amorphous mass containing about 95% AS2O3 condenses in
the kitchens nearest the furnace and is reprocessed. The
bulk of the trioxide is condensed in the kitchens with
temperature ranges of 180-120°C. The purity of the
arsenic obtained from these kitchens is from 99 to 99.9%.
The dust which exits from the kitchens at a temperature
of 90-100°C is caught in the baghouse. It assays about
90% AS2O3 and may be sold as a crude arsenic or repro-
cessed."
A flow diagram for the production of arsenic trioxide is
presented in Figure 6.
Production
Statistics: The quantity of arsenic trioxide produced, imported and
exported are presented from 1940 through 1974 in Figure
7. Since the beginning of 1970 the production of arsenic
trioxide has steadily decreased. However, imports have
slightly increased during the same period of time.
Emissions:	The only emission directly related to the manufacture of
arsenic trioxide and not to the copper smelter are from
the handling of the flue dust and from the kitchens.
Reported emissions from the flue dust handling system
are 20 tons of arsenic trioxide per year. Emissions
from the kitchens are not known because they are vented
to a common price of control equipment.
30
GCA/TECHNOLOGY DIVISION QOA

-------
llo fee convened 1o HjSQ,)	White orientc
and	(or
wotte qoirt lo dock	market
Figure 6. Flow diagram for the manufacturing of arsenic trioxide
from a copper smelter^
31
GCA/TECHNOLOGY DIVISION A

-------
200
100
90
00
70
60
30
w
to
O
o
>
n
x
z
o
5
Q
g
<

O
z
o
to
z
o
cc
o
X
CO
b.
O
to
Q
Z
<
to
o
IMPORTS
PRODUCTION
1940 1945
I9S0
I9S5
I960
1965
1970
1975 I960
1985
1990
ACTUAL YEARS
Figure 7. Arsenic trioxide production

-------
Arsine
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Boiling
Point:
Uses:
Manufacturing
Process:
Production
Statistics:
Arsenic hydride, arseniuretted hydrogen
AsH3
Colorless gas, soluble in water, slightly soluble in
alcohol, alkalies
77.93
-116.3°C
-55°C
Doping agent for solid-state electronic components,
semiconductor industry
Produced by the action of sulfuric acid or metallic
zinc mixed with arsenic compounds
1974 - 8 to 10,000 pounds
33
GCA/TECHNOLOGY DIVISION OOA

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Cacodylic Acid
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Manufacturing
Process:
Dimethylarsinic acid, alkargen
(CH3)2 As 0 OH
Colorless, odorless, deliquescent crystals; soluble in
water, alcohol, and acetic acid, insoluble in ether
Contact herbicide capable of defoliating or desiccating
a wide variety of plants. Fifty percent used for non-
selective weed control, AO percent used for cotton de-
foliation, 1 percent for forest management uses (control
of bark beetles), 9 percent for other purposes including
lawn rennovation.
A process developed byL.R. Schanhals; U.S. Patent
3,322,805; May 30, 1967; assigned to O.M. Scott & Sons
Company yields an improved means of manufacturing
cacodylic acid. As shown in Figure 8, solid arsenic
trioxide is mixed with solid sodium hydroxide and water.
The materials react to produce sodium arsenite as shown
in the equation below.
Reaction 1
Sodium hydroxide in excess of the stoichiometric amount
required for reaction is added. This is done because
yields in Reaction 2 (shown below) are increased by the
presence of sodium hydroxide. Excess sodium hydroxide
must be also provided to compensate for that depleted by
hydrolysis reaction of the sodium hydroxide with the
methyl chloride which competes with Reaction 2 below.
This hydrolysis reaction proceeds as follows:
As203 + 6Na0H
2As(ONa)3 + 3H20
CH^Cl + NaOH
NaCl + CH30H
34
GCA/TECHNOLOGY DIVISION ®@A

-------
CHlCl
froeoi of
tCHj)jA»00M
CH^AtOlOHlj
0*1 (ON),
Ht0
(CHj^AtOOH
r *«Ci
m«zso4
CHJk>0(0H)
troces^oA.iOHi,
fr HjO Sol*

	
N09SO4
Stun. — ..
i
QONCENTRATt
STORAGE

0RY1N0
(OPTIONAL)
Al (OHVj
CMMO (OHIj
No CI
CMjOH
io H20 Sola
ch3oh
trocoi
(CHV2 AtOOH
- N«CI
>•0 (OH).
(OH)
f ""
N,
JCHjA
\o»« I
2
i-J
T
WojSO« |
CMjOH
in MjO Sola
CHjOH
H,0
PRECIPITA-
TION
(cnyAsOOH
DRYING

•neot of

CNjAsO
-------
After Reaction 1 is complete, the aqueous sodium arsenite
solution containing excess sodium hydroxide is fed into
a pressure reactor. The solution is brought to the de-
sited temperature, which is between 125° and 235°P (155°
to 185°F being preferred), and reacted under pressure
with superheated methyl chloride to form disodiutn methyl
arsenate (DSMA), the reaction proceeding as follows:
Reaction 2
h2o
As(ONa)3 + CH3C1	CH3AsO(ONa>2 + NaCl
The DSMA solution produced by methylating the sodium
arsenite is reacted with sulfur dioxide gas in the same
pressure reactor to produce methyl arsineoxide. By
using S02 gas, substantially better results are achieved
than is possible by using sulfurous acid. This third
reaction proceeds as follows:
Reaction 3
h2°
CH3AsO(ONa)2 + S02	KIH^sO + Na^O^
The reaction is very rapid at temperatures below 200°F
and at any pressure. After the reaction is complete 5
to 15 minutes), the excess SO2 is outgassed using an inert
gas, preferably nitrogen. The outgassing and subsequent
blanketing with inert gas is of great importance in ob-
taining high yields of cacodylic acid. This is because
air oxidation of mechyl arsineoxide and its salts occurs
very readily and must be prevent to avoid the loss of
methyl arsineoxide. This oxidation reaction is as
follows:
2CH3AsO + 02 + 2R20 	*-2CH3AsO(OH)2
If an inert atmosphere is not maintained over the solu-
tion, high losses of yield will result. Other inert
gases such as C02, helium, and the like may be used, but
nitrogen is preferred.
With the inert atmosphere still blanketing the solution,
sodium hydroxide is added to the reaction mixture in
the pressure reactor. This reacts with the methyl
arsineoxide to form disodium methyl arsenite as follows:
36
GCA / TECHNOLOGY DIVI5ION ©@A
-------
Reaction 4
»2°
CH3AsO + 2NaOH 	CH3As DSMA (ONa)2 + H2>
An excess of sodium hydroxide over the stoichiometric
amount is added in this step to increase the yield of
disodium methyl arsenite from Reaction 4. As was the
case with Reaction 1 above, other caustic materials,
such as potassium and lithium hydroxide and the like,
may be used.
After Reaction 4 is complete, the disodium methyl arsenite
solution is brought to reaction temperature and reacted
with superheated methyl chloride to form sodium dimethyl
arsenate, the reaction proceeding as follows:
Reaction 5
h2o
CH3As(ONa)2 + CH-jCl	(CH^AsO MSMA (ONa) + NaCl
The products of Reactions 2 through 5 (all of which are
carried out in the same pressure reactor) are present in
a slurry which is pumped out of the reactor. The solids
are then removed by conventional methods, preferably
by pumping the reaction products to a settling tank and
cooling them. Most of the Na2SO^, some NaCl, and some
reaction by-products have precipitated in the pressure
reactor. Residual amounts remaining in solution precipi-
tate out in the settling tank as the solution cools.
The sodium dimethyl arsinate solution from the settling
tank is acidified to produce dimethyl arsinic (cacodylic)
acid from its sodium salt. Suitable acids including
sulfuric, nitric, phosphoric, and the like may be used
in the acidification step, but hydrochloric is preferred.
The typical acidification reaction involved is shown be-
low with HC1.
Reaction 6. „ _
h2o
(CH3)2AsO(ONa) + HC1 -~	AsO Cacodylic Acid (OH) + NaCl
The temperature and pressure at which this reaction is
carried out are not critical, and ambient conditions are
preferably used for economy.
37
GCA TECHNOLOGY DIVISION ©©A
-------
The preferred method utilizes an additional optional
oxidation step to reduce the toxicity, odor, etc. of
the reaction mass. Either the solution containing the
arsinic acid or its salt may be oxidized by a suitable
oxidizing agent. Examples of appropriate agents are:
sodium hypochlorite, iodine, potassium permanganate,
bromic acid, calcium hypochlorite, hypochlorous acid,
hydrogen peroxide, and the like. A preferred oxidizing
agent is sodium hypochlorite. Typical reactions which
occur in this oxidation step are as follows:
Reaction 7
CH^AsO + H20 + NaOCl	CH3AsO(OH>2 + NaCl
As(ONa)3 + NaOCl	^OAs(ONa)3 + NaCl
As(OH)3 + NaOCl	OAs (OH)3 + NaCl
As203 + NaOCl	+ 2NaC1
The temperature and pressure at which the oxidation re-
action is carried out are not critical. Again, ambient
conditions are preferred for economic reasons. The se-
quence of the acidification (Reaction 6) and oxidation
steps can be reversed, if desired, with no change in the
resulting end product.
The arsinic acid or salt solution is pumped to an evapor-
ator or similar device and water and methanol there re-
moved, precipitating additional quantities of NaCl and
Na2SO^. The solids may be removed from the solution by
any conventional means. In the preferred process, the
hot concentrate is first cooled in a settling tank and
the insoluble impurities then removed. Additional solu-
tion is then removed from the solids by conventional de-
vices such as filters or centrifuges and the mother
liquor added to the solution removed in the settling tank.
The concentrated dimethyl arsinic acid or arsinic acid
salt solution may be used as such as an intermediate or
as a raw material in herbicides, defoliants and the like
or may be additionally processed. For example, the
solution may be further evaporated and dried to give
solid dimethyl arsinic acid or salt product.
38
GCA/TECHNOLOGY DIVISION ®©A
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This process description was obtained from Agricultural
Chemicals Manufacture.^
Emissions:	Emissions of arsinic from this manufacturing process
will occur from the handling of arsenic trioxide from
the venting of the reactor, and from the purification
of the final product. Emission rates are similar to
those from the manufacturing of MSMA. See process
description for MSMA.
39
GCA/TECHNOLOGY DIVISION ©@A
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Calcium Arsenate
Synonyms:
Formula:
Properties:
Tricalcium ortho-arsenate
White powder, slightly soluble in water, soluble In
dilute acids, decomposes on beating
Molecular
Weight:
Uses:
Manufacturing
Process:
398.06
Insecticide, germicide
Commercially calcium arsenate is made for arsenic acid
and calcium hydroxide. The raw materials are arsenic
trioxide, which is oxidized with nitric acid to form
arsenic acid.
As2 03 + 2HN03
arsenic nitric
trioxide acid
As. CL + H_0 + N„0
2 5
2 3
arsenic water nitrogen
pentoxide	trioxide
As205 + 3H20
arsenic water
pentoxide
2HAs0,
3 4
arsenic acid
3Ca (0H)2 + 2H3As04
calcium
hydroxide
arsenic
acid
Ca3(As04)2
calcium
arsenate
6fl20
water
When the reaction is complete, the precipitated calcium
arsenate is separated by filtration, dried, milled and
packaged. See Figure 9.
Production
Statistics:
The production of calcium arsenate has	steadily dropped
over the past several years. The most	recent figure
for the production of calcium arsenate	is 940,000
pounds in 1971. See Figure 10.
40
GCA/TECHNOLOGY DIVISION ©OA
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ARSENIC ACID
Figure 9.
EMISSION POINTS
Flow diagram for production of calcium arsenate
-------
200
(S)
o
o
>
m
n
x
Z
o
5
Q
g
<
c/>
O
Z
CO
Q
z
3
O
a
CO
z
o
J
¦J
CALCIUM ARSENATE
COMMERCIAL OR 70 %
Ca3 [As04](2)
1940
1950
I960 1965
ACTUAL YEARS
1975 1980
1985
1990
Figure 10. Domestic production of calcium arsenate
©
~
-------
Calcium Arsenite
Synonyms:
Formula:
Properties:
Molecular
Weight:
Uses:
Manufacturing
Process:
Production
Statistics:
None.
CaAsO^H
White granular powder, insoluble in water, soluble in
acids
164
Insecticide, germicide
Precipitation out of a mixture of a solution of an
alkaline arsenite and a solution of a calcium salt.
No data available.
A3
GCA/TECHNOLOGY DIVISION ©QA
-------
Copper Arsenate
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Manufacturing
Process:
Cuprous arsenate, basic copper arsenate
Cu (CuOH) AsO^
Light blue or bluish-green powder, variable composi-
tion contains 33 percent (approximately) copper,
and 29 percent (approximately) arsenic, soluble in
dilute acids and ammonium hydroxide, insoluble in
alcohols and water
Decomposes
Insecticide, fungicides, wood preservatives as chromated
copper arsenate
Prepared from arsenic acid, copper sulfate and lime.
The calcium sulfate produced in the reaction is not re-
moved and the final product contains between 41 and
46 percent of the basic copper arsenate.
Six formulations of chromated copper arsenate are pre-
sented below*^
1. K2CR0? - 45%
2. Na2CR207 - 39%
CUSO4 - 22.4%
As205 • 2H20 - 33.4%
Na^As207 - 5.2%
As202 * 2^0 - 20%
CuS04 • 5H20 - 35%
4. K2CR207 - 40%
CuS04 • 5H20 - 32%
As205 • 2H20 - 21%
Na4As207 - 7%
3. Na2CR207 - 31.7%
CuS04 - 29.7%
As2°5 • 2H2) - 26.3%
Na4As207 - 12.3%
5. Na2CR207 • 2H20 - 32%
CUSO4 - 30%
As205 • 2H20 - 28.5%
Na4As207 - 9.5%
6. CRO3 - 26.6%
CuO - 14.8%
As205 - 34%
H20 - 24.6%
44
GCA/TECHNOLOGY DIVISION 0®A
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Production
Statistics: The following usage figures are of chromated calcium
arsenate used as a wood preservative.^
1968
3,168,000
lb
1969
4,668,000
lb
1970
6,033,000
lb
1971
8,572,000
lb
1972
9,748,000
lb
1973
11,667,000
lb
45
GCA/TECHNOLOGY DIVISION
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Copper Arsenite
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Manufacturing
Process:
Production
Statistics:
Cupric arsenite, copper orthoarsenite, Sheel's green
Variable, CuH AsO^ or Cu^AsO^^ *
Fine light-gre^n powder, soluble in acids, insoluble
in water and alcohol
187.5 or 490.6
Decomposes
Insecticide, pigments
Reacting copper sulfate and sodium arsenite
No data available.
46
GCA/TECHNOLOGY DIVISION ©©A
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Fluor Chrome Arsenite Phenol
This pesticide is a formulation and will not be looked at in this re-
port. Reported usage for 1968 through 1972, however, is presented
below.*"*
1968
3,971,000
lb
1969
4,539,000
lb
1970
2,687,000
lb
1971
2,169,000
lb
1972
1,914,000
lb
1973
1,683,000
lb
47
GCA/TECHNOLOGY DIVISION Q®A
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Lead Arsenate
Synonym:
Formula:
Properties:
Lead orthoarsenate
Pb3(As04)2
White crystals, soluble in nitric acid, insoluble
in water
MolecuLar
Weight:
899.57
Melting
Point:
Uses:
1042 C decomposes
Insecticide, herbicide
Manufacturing
Process:
Lead arsenate is made from arsenic acid and lead
hydroxide. The raw materials are arsenic trioxide,
which is oxidized with nitric acid to form arsenic
acid.
ASjOj +
2HN0-
arsenic nitric
trioxide acid
As2 0^ +
arsenic
pentoxide
h2o
water
+ N2°3
nitrogen
trioxide
As205 + 3H20
arsenic water
pentoxide
2H,AsO.
3 4
arsenic
acid
3Pb(0H) + 2H,AsO,
2	3 4
Pb3(As04)2 + 6H20
lead
hydroxide
arsenic
acid
lead
arsenate
water
Similar to the calcium arsenate process, when the re-
action is complete the precipitated lead arsenate
is separated by filtration, dried, milled, and packaged.
See Figure 11.
48
GCA/TECHNOLOGY DIVISION 6GA
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Production
Statistics: The production of lead arsenate, like other inorganic
arsenical, has dropped over the past several years.
The latest production figure is 6,582,000 pounds in
1972. See Figure 12.
49
GCA/TECHNOLOGY DIVISION © A
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ARSENIC ACID
¦ EMISSION POINTS
Figure 11. Flow diagram for production of lead arsenate
-------
200
wi
o
o
n
x
z
o
5
g
<
C£
o
z
V)
a
z
3
O
a
u.
o
tn
z
o
-LEAD ARSENATE
(ACIO AND BASIC)
1940 1945
1950
1955
I960
1965
1970
1975 1980
1985
1990
ACTUAL YEARS
Figure 12. Lead arsenate production
£
-------
Monosodium Methylarsonate (MSMA)
Synonym:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Monosodium methanearsonate
CH^AsO (ONa) OH
White to faint yellow liquid aqueous solution
161.94
Anhydrous form decomposes, hydrated form 115 to 119 C
Contact herbicide to control weeds, used on lawns and
certain noncrop areas.
Manufacturing
Process:
MSMA is manufactured from DSMA by treatment with
sulfuric acid.
/
ONa
2CH AsO(ONa) + HoS0,
3	2 2 4
2CH, As	+ Na SO
3 i.Nm 2 4
DMSA
sulfuric
acid
0
MSMA
sodium
sulfate
See description of cacodylic acid reactions 1 through 5.
Production
Statistics:
Emissions:
Very limited data is available on the production of
MSMA
1972	estimate
1973	estimate
24 million pounds
32 million pounds
14
6,14
Very limited data exists for emissions from the manu-
facturing of MSMA. One firm has, however, reported
the data from tests performed at its plant. The follow-
ing are the results of these tests.
1. Arsenic trioxide drum handling.
Controlled (99.2%) emission of 0.090 lb
of arsenic/day.
52
GCA/TECHNOLOGY DIVISION ©@A
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Methylation reactor venting
Uncontrolled emissions of 0.210 pounds of
arsenic/day.
Evaporator
Uncontrolled emissions of 0.0061 pounds of
arsenic/day.
Spray dryer
Controlled (99.2 percent) emission of 0.260
pounds of arsenic/day.
53
GCA/TECHNOLOGY DIVISION OCA
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Disodium Methylarsonate (DSMA)
Synonym:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Manufacturing
Process:
Disodium methanearsonate
CH3 As 0(0Na)2
White fine crystalline powder, odorless
183.93
132 to 139°C slowly decomposes at elevated temperatures
Contact herbicide to control weeds
DSMA is manufactured from arsenic trioxide, sodium
hydroxide, and methyl chloride
As2 03 + 6Na OH
2Na3 As03 + 3H20
arsenic sodium	sodium
trioxide hydroxide arsenite
water
Na-jAsO-j + CH3 CI
sodium	methyl
arsenite chloride
CH3AsO(ONa)2 + NaCl
DSMA
sodium
chloride
Production
Statistics:
See description of cacodylic acid reactions 1 through 4.
1972	estimate
1973	estimate
6 million pounds
8 million pounds
14
6,14
54
GCA/TECHNOLOGY DIVISION « A
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Mcthanearsonic Acid (Calcium Salt)
This compound is no longer being produced.
55
GCA/TECHNOLOGY DIVISION ®A
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Methanearsonic Acid (Ammonium Salt)
15,16
This compound is no longer being produced.
56
GCA/TECHNOLOGY DIVISION ®QA
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Copper Acetoarsenite
Synonyms:
Formula:
Properties:
Molecular
Weight:
Uses:
Manufacturing
Process:
Production
Statistics:
Paris green, cupric acetoarsenite, Schweinfort green,
imperial green, kings green, moss green
(CuO)3 As203 * Cu (C2H302)2
Emerald green powder, soluble in acids, insoluble in
alcohol and water
618.15
Insecticide, pigments, wood preserving preparations
Manufactured by reacting sodium arsenite with copper
sulfate and acetic acid
No data available.
57
GCA/TECHNOLOGY DIVISION ®A
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Sodium Arsenate
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Manufacturing
Process:
Production
Statistics:
Sodium O-arsenate
Na AsO. • 12H 0
3 4	2
Clear colorless crystals, soluble in water, slightly
soluble in alcohol and glyceral, insoluble in ether -
424.10
86.3°C
Herbicide, insecticide, medicine, dry colors, textiles,
manufacturing other arsenates
Manufactured by heating arsenic trioxide with sodium
nitrate, dissolving in water and then crystallized
No data available.
58
GCA/TECHNOLOGY DIVISION©® A
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Sodium Arsenite
Synonyms:	Sodium orthoarsenite, sodium metarsenite
Formula:	Na^AsO^ - ortho
NaAsC^ - meta
Properties: Grayish white powder, which absorbs carbon dioxide
from the air, soluble in water, slightly soluble in
alcohol
Molecular
Weight:
Ortho - 192
Meta - 129.91
Uses:
Insecticides, hide preservative, herbicide, antiseptic,
dyeing
Manufacturing
Process:
Manufactured from reacting arsenic trioxide with
sodium hydroxide
As203 + 2NaOH -~
arsenic sodium
trioxide hydroxide
2NaAs02 + H20
sodium	water
metarsenite
AS2°3 +
6NaOH
arsenic sodium
trioxide hydroxide
2Na3As03 + 3H20
sodium	water
orthoarsenite
Production
Statistics:
8 million pounds used in 1965. No other data avail-
able.
59
GCA/TECHNOLOGY DIVISION ®@A
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Zinc Arsenate
Synonyms:
Formula:
Properties:
Molecular
Weight:
Melting
Point:
Uses:
Manufacturing
Process:
Zinc orthoarsenate
2N3(As04)2 • 8H20
White odorless powder, insoluble in water, soluble
in acids and alkalies
618.09
Decomposes at 100°C
Insecticide
Produced by reacting a solution of sodium arsenate
and a soluble zinc salt
Production
Statistics:
No data available.
60
GCA/TECHNOLOGY DIVISION @®A
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SECTION VII
REFERENCES
1.	U.S. EPA. State of the art for the Inorganic Chemicals Industry:
Inorganic Pesticides. March 1975. EPA-600/2-74-009a.
2.	Production Distribution, Use and Environmental Impact Potential
of Selected Pesticides 1974. Office of Pesticide Programs.
EPA 540/1-74-001.
3.	Synthetic Organic Chemicals. 1973.
4.	The Pesticide Review 1973. U.S.D.A. Bulletin No. M-75-10.
5.	CEH. Stanford Research Institute.
6.	Screening Study to Develop Background Information and Determine
the Significance of Air Contaminant Emissions From Pesticide
Plants. Battelle. March 5, 1975.
7.	Initial Scientific Minieconomic Review of Cacodylic Acid. Midwest
Research Institute. Jan. 1975. (draft copy)
8.	Conversation with Puget Sound Air Pollution Control Agency.
June 1975.
9.	National Inventory of Sources and Emissions; Arsenic, Beryllium,
Manganese, Mercury, and Vanadium 1968. W.E. Davis and Assoicates.
May 1971. APTO 1507.
D
10.	Sittig, M. Agricultural Chemicals Manufacture. Noyes Data Corp.
New Jersey. 1971.
11.	KirC« and Othmer. Encyclopedia of Chemical Technology, Vol. 2,
2nd edition. John Wiley and Sons, New York. 1963.
12.	McQuire, A.J. American Wood Preservers Association. Ground
Contact Retentions for Copper-Chrome-Arsenate Preservatives.
1972.
61
GCA/TECHNOLOGY DIVISION 6 ~
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13.	Gill, t. and Phelps, R. Wood Preservation Statistics 1973.
American Wood Preservers Association, 1974.
14.	Initial Scientific and Minieconomic Review of MSMA/DSMA. Midwest
Research Institute. October 1974. (draft copy)
15.	Personal Communication with Vineland Chemical Co. Mr. Bob Neso.
June 1975.
16.	Personal Communication with W.A. Cleary Co. July 1975.
62
GCA/TECHNOLOGY DIVISION O A
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