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AIR POLLUTION ASPECTS
OF
CHLORINE GAS
Prepared for the
National Air Pollution Control Administration
Consumer Protection & Environmental Health Service
Department of Health, Education, and Welfare
(Contract No. PH-22-68-25)
Compiled by Quade R. Stahl, Ph.D,
Litton Systems, Inc.
Environmental Systems Division
7300 Pearl Street
Bethesda, Maryland 20014
September 1969
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FOREWORD
As the concern for air quality grows, so does the con-
cern over the less ubiquitous but potentially harmful contami-
nants that are in our atmosphere. Thirty such pollutants have
been identified, and available information has been summarized
in a series of reports describing their sources, distribution,
effects, and control technology for their abatement.
A total of 27 reports have been prepared covering the
30 pollutants. These reports were developed under contract
for the National Air Pollution Control Administration (NAPCA) by
Litton Systems, Inc. The complete listing is as follows:
Aeroallergens (pollens) Ethylene
Aldehydes (includes acrolein Hydrochloric Acid
and formaldehyde) Hydrogen Sulfide
Ammonia Iron and Its Compounds
Arsenic and Its Compounds Manganese and Its Compounds
Asbestos Mercury and Its Compounds
Barium and Its Compounds Niclcel and Its Compounds
Beryllium and Its Compounds Odorous Compounds
Biological Aerosols Organic Carcinogens
(microorganisms) Pesticides
Boron and Its Compounds Phosphorus and Its Compounds
Cadmium ^and. Its Compounds Radioactive Substances
^Chlorine Gas"1 Selenium and Its Compounds
Chromium and Its Compounds Vanadium and Its Compounds
(includes chromic acid) Zinc and Its Compounds
These reports represent current state-of-the-art
literature reviews supplemented by discussions with selected
knowledgeable individuals both within and outside the Federal
Government. They do not however presume to be a synthesis of
available information but rather a summary without an attempt
to interpret or reconcile conflicting data. The reports are
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necessarily limited in their discussion of health effects for
some pollutants to descriptions of occupational health expo-
sures and animal laboratory studies since only a few epidemio-
logic studies were available.
Initially these reports were generally intended as
internal documents within NAPCA to provide a basis for sound
decision-making on program guidance for future research
activities and to allow ranking of future activities relating
to the development of criteria and control technology docu-
ments. However, it is apparent that these reports may also
be of significant value to many others in air pollution control,
such as State or local air pollution control officials, as a
library of information on which to base informed decisions on
pollutants to be controlled in their geographic areas. Addi-
tionally, these reports may stimulate scientific investigators
to pursue research in needed areas. They also provide for the
interested citizen readily available information about a given
pollutant. Therefore, they are being given wide distribution
with the assumption that they will be used with full knowledge
of their value and limitations.
This series of reports was compiled and prepared by the
Litton personnel listed below:
Ralph J. Sullivan
Quade R. Stahl, Ph.D.
Norman L. Durocher
Yanis C. Athanassiadis
Sydney Miner
Harold Finkelstein, Ph.D.
Douglas A. Olsen, Ph0D.
James L. Haynes
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The NAPCA project officer for the contract was Ronald C.
Campbell, assisted by Dr. Emanuel Landau and Gerald Chapman.
Appreciation is expressed to the many individuals both
outside and within NAPCA who provided information and reviewed
draft copies of these reports. Appreciation is also expressed
to the NAPCA Office of Technical Information and Publications
for their support in providing a significant portion of the
technical literature.
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ABSTRACT
Low concentrations of chlorine gas in the atmosphere,
e.g. 3,000 ug/m3 (1 ppm), can cause irritation of the eyes,
nose, and throat; larger doses can cause damage to the lungs
and produce pulmonary "edema, pneumonitis, emphysema, or
bronchitis. Chlorine gas is known to have caused injury
and death to humans and animals as well as to have damaged
plant life. Its highly corrosive nature suggests the possi-
bility of material damage; however, no instances of damage
by atmospheric chlorine have been reported in the literature.
Possible sources of chlorine in the atmosphere are
industrial liquefication processing, other industrial uses
of chlorine, and accidental leakage during storage or trans-
portation. Production of chlorine has doubled in the past
10 years and is expected to continue at this rate of in-
crease for several years. No information is currently availa-
ble on the concentrations of chlorine gas in ambient air.
Effective methods are available for control of chlo-
rine emissions. No information has been found on the eco-
nomic costs of chlorine air pollution or on the costs of its
abatement.
Methods of analysis are available; however, they are
not sufficiently sensitive or selective for determining
atmospheric concentrations of chlorine.
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CONTENTS
FOREW3RD
ABSTRACT
1. INTRODUCTION 1
2. EFFECTS ' 2
2.1 Effects on Humans 2
2.1.1 Acute Effects-7 2
2.1.2 Chronic Effects-'' 5
2.1.3 Sensory Thresholds 9
2.1.4 Synergistic Effects 10
2.1.5 Chlorine Gas Exposure to Communities-
Through Accidents 11
2.2 Effects on Animals1/ 14
2.2.1 Commercial and Domestic Animals-7 ... 14
2.2.2 Experimental Animals*' 14
2.3 Effects on Plants/ 15
2.3.1 Phytotoxicity 15
2.3.2 Sensitivity of Plants 16
2.3.3 Effect of Moisture 17
2.3.4 Effect of Light 18
2.3.5 Effect of Water Stress 19
2.3.6 Plant Accumulations 19
2.3.7 Episodes of Plant Damage 22
2.4 Effects on Materials 23
2.4 Environmental Air Standards^ 24
3, SOURCES'' 25
I
3.1 Natural Occurrence" 25
3.2 Production Sources- 25
3.2.1 Electrolytic Diaphragm Cells 26
3.2.2 Electrolytic Mercury Cells 28
3.2.3 Fusion Electrolysis of Chloride Salts. 28
3.2.4 Other Processes 28
3.3 Product Sources 29
3.3.1 Chlorinated Organic Chemicals .... 29
3.3.2 Other Organic Chemicals 30
3.3.3 Inorganic Chemicals 30
3.3.4 Other Uses 30
3.4 Environmental Air Concentrations 31
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4. ABATEMENT^ 32
4.1 Water Scrubbers 33
4.2 Alkali Scrubbers 34
4.3 Carbon Tetrachloride Scrubbers 34
5. ECONOMICS 35
6. METHODS OF ANALYSIS _ 36
6.1 Sampling Methods 36
6.2 Qualitative and Seiniquantitative Methods . . 37
6.3 Quantitative Methods 38
7. SUMMARY AND CONCLUSIONS 41
REFERENCES
APPENDIX
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LIST OF TABLES
1. Reactivity of Chlorine ............... 61
\s
2. Physical Properties of Chlorine .......... 62
3. Summary of Reported Human Health Effects of Inhalation
of Chlorine .................... 63^
4. Summary of Reported Toxic Effects of Inhalation of ,
Chlorine on Animals ................ 65 ^
5. Typical Gross Findings at Autopsy of Rats and Mice
Which Died During Exposure to Chlorine (C12 ) or Were
Sacrificed Immediately after Gas Treatment ..... 69
6. Summary of Reported Effects of Chlorine Gas Exposure ,
on Plant Life ................... 70 ^'
7. Chlorine Production in the United States
8. Major Producers of Chlorine Gas and Liquid in the
U.S ......................... 81
9. Consumption of Chlorine by Uses, 1963-64 ...... 82
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1. INTRODUCTION
Chlorine is a dense, greenish-yellow gas with a
distinctive, irritating odor. It is noted for its very
strong oxidizing and bleaching properties. Because of
these properties, chlorine can be extremely hazardous to all
life forms, as well as corrosive to metals and other mate-
rials. Although chlorine is not flammable, it can support
combustion, and many materials (such as hydrogen) and many
metals can burn in a chlorine atmosphere—sometimes with
explosive violence (see Tables 1 and 2 in the Appendix for
the reactivity and the physical properties of chlorine).
Several incidents of accidental chlorine leakage have
led to injury and death of humans and animals, and damaged
many species of plants.
The production of chlorine in the United States has
doubled in the past 10 years and is projected to continue to
increase at a rate of approximately 7 percent per year. The
largest users of chlorine are the chemical industry and the
pulp and paper industry. The major commercial source of
chlorine is the electrolysis of alkali chloride solutions-
The chlorine is usually liquefied before use or storage.
The liquefication process can be an important source of chlo-
rine atmospheric emissions if not carefully controlled.
Effective methods are available for control of chlorine
emissions.
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2. EFFECTS
Chlorine gas is a very strong oxidizing agent, capable
of reacting with organic as well as inorganic materials. This
property makes it dangerous to humans, animals, plants, and
numerous materials. Furthermore, in the presence of moisture
chlorine reacts to form hypochlorite, another strong oxidiz-
ing agent (the active ingredient in liquid household bleach),
and hydrochloric acid, one of the common strong acids. If
these compounds are formed in the mucous membranes of the
body from chlorine present in the atmosphere, damage to the
tissues could result.
2.1 Effects on Humans
The sensitivity of humans to chlorine gas varies great-
er o
ly among individuals. The main effect which has been noted
is the irritating and corrosive action on the mucosa of the
eyes, nose, throat, and respiratory tract. Exposure to high
concentrations of chlorine can damage the lungs and has resulted
in pulmonary edema, ' ' ' pneumonitis, ' ' emphysema,
52,81 and bronchitis. '4/1° In extreme cases, the damage to
the lungs may be severe enough to result in death by suffoca-
1ft 94
tion. Available evidence suggests that humans can develop
some tolerance to low concentrations of chlorine.
2.1.1 Acute Effects
At chlorine gas concentrations of 3,000 |ag/m3 of air
(1 ppm) or less, persons, particularly those not accustomed to
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chlorine become disturbed and exhibit noticeable symptoms
of irritation.^'^ Depending on the individual's sensi-
tivity, irritation may first be noted in the eyes, nose,
or throat. (The more recent studies indicate that the
odor threshold is also below 3,000 ug/m3; see Section 2.1.3).
Irritation of these areas will increase during the first
hours of exposure. However, men may work without inter-
ruption in an environment at concentrations of chlorine of
3 R O
3,000 to 6,000 |jg/m . Many reports indicate that persons
habitually exposed to chlorine develop some degree of toler-
ance. Dixon and Drew, however.- reported that there is
no tolerance in men, but rather, that workers seem to be
able to voluntarily reduce their respiratory tidal volume
64
in the presence of chlorine. At any rate, Kramer reports
that workers who are continually exposed to chlorine are
able to tolerate 15,000 to 25,000 |ag/m? (5-8 ppm) for
significantly long periods.
Normally, chlorine exposures of 9,000 to 18,000 |ag/m3
(3 to 6 ppm) cause a stinging or burning sensation to eyes,
50
nose, and throat. This is in contrast to earlier data of
Fieldner et ajl. , ' ^4 still generally used, which give the
threshold concentration for throat irritation as approximately
45,000 |ag/m3 (15.1 ppm) and for coughing as approximately
90,000 |ag/m3 (30.2 ppm). Furthermore, a headache may develop,
C 0
caused by irritation of the accessory nasal sinuses. ^
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Exposure of sufficient duration may cause redness and watering
of eyes, sneezing, coughing, and huskiness or loss of voice.
Moreover, bleeding from the nose may result, and sputum from
the pharynx and trachea may contain blood. Muscular soreness,
other than from extensive coughing, is absent. Bronchospasm
of a relatively transient nature occurs in almost all chlorine
exposures, including the minor exposures.
Exposure to environments containing chlorine concentra-
tions of 40,000 to 60,000 ^ig/nr3 (14 to 21 ppm) for 30 to 60
minutes is dangerous, while concentrations of 290,000 |_tg/m
(100 ppm) cannot be tolerated for more than one minute. ^
Symptoms observed in persons following a heavy exposure
to chlorine include choking, nausea, vomiting, retching, dyspnea,
17 ^i ft
burning eyes, headache, dizziness, anxiety, and syncope. '
Examinations after exposures reveal an increase in body tempera-
ture, anorexia, diffuse cracking rales, and acute conjunctival
infection with profuse tearing and photophobia; muscular weak-
ness and a decrease in stamina are also noted. Heavy exposure
to chlorine may also lead to respiratory disorders (see Section
2.1.2).
Inhalation of massive doses of chlorine gas will result
in destruction of tissues. If damage to lung tissue is exten-
sive, death by suffocation soon occurs.15 Moreover, with
sudden extreme exposures, shock may occur, with a spontaneous
constriction of the trachea or bronchi to a degree which causes
suffocation. Deaths from chlorine inhalation will usually
occur within minutes, or, at most, within several days.
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Chlorine is very reactive with mucosa; therefore, the
effects on the body are normally encountered only in a localized
area. Hence, entrance of chlorine or its reaction products
into the blood circulation occurs only from massive exposures
(such as 2 g/m3 of chlorine or 2,000 ppm, which is rapidly
fatal).
A summary of the reported effects on man due to inhala-
tion of chlorine gas is given in Table 3 in the Appendix.
2.1.2 Chronic Effects
Generally, it is reported that low concentrations of
chlorine gas do not cause chronic effects. A common state-
ment is that, based on examination of workers exposed daily
to detectable concentrations of chlorine, there are no chronic
18 24
systemic effects. ' However, there is a paucity of data
available on exposures to low concentrations over long periods
of time. Recent studies indicate that some of the early data
may be invalid, e.g., the odor threshold value has decreased by
a factor of ten with recent data (see Section 2.1.3). Further-
more, some of the other physiological response data discussed
in Section 2.1.1 suggest that the stated absence of chronic
effects at low concentrations of chlorine needs further verifi-
cation .
90
Patil et al. studied 332 diaphragm cell workers ex-
posed to chlorine. Time-weighted average (TWA) exposures to
chlorine ranged from 18 to 4,260 M-g/m3 with a mean of 450+ 870
|-ig/m3 . Significant correlations* were found between
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exposure to chlorine and various effects, i.e., tooth decay,
anxiety and dizziness, and leukocytosis. Hematocrit readings
showed a significant inverse correlation with exposure. These
investigators also noted that workers were in good health, and
not affected in any clinically duplicable way by the years of
continual exposure to low concentrations of chlorine. Acute
exposure did cause temporary illness, but without evidence of
94
permanent damage. In 1964, Pendergrass reported that a
study was in progress to determine the effect of long term
exposure (several years) to low concentrations of chlorine
(< 3,000 ng/m3).
100
Ronzani in 1909 studied men working in bleaching
rooms, exposed to chlorine concentrations of approximately
15,000 ug/m3 of chlorine (5 ppm) in air. He found that these
men aged prematurely, suffered from disease of the bronchi, and
were predisposed to tuberculosis. In addition, he noted that
their teeth were corroded from the hydrochloric acid produced
by reaction of chlorine with the moisture in the mouth, and
also observed inflammation or ulceration of the mucous
membrane of the nose.
Recognition of the danger of continuous exposure to
low concentrations is further supported by the results described
by Skjanskaja and Rappoport. These investigators exposed
rabbits to concentrations of chlorine ranging from 2,000 to
5,000 |-ig/m3 (0.7 to 1.7 ppm) over periods lasting up to 9
months. This produced a loss of weight and an increased
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incidence of respiratory disease among the rabbits. Further-
more, other investigators have reported that in experiments
with guinea pigs, small concentrations of chlorine accelerate
the course of experimental tuberculosis. These studies tend
to disprove the earlier belief of Baskerville8'9'10 that small
amounts of chlorine in a working environment decrease the
incidence of respiratory diseases among workers, possibly by
sterilizing the air.
As a consequence of a heavy exposure to chlorine, a
person may develop lung ailments, including pulmonary edema,
17,58,63,81 pneumonitis,17'63'64 emphysema,52'81 and bron-
chitis. 52,64,107 rjr^g cominon opinion in the literature is
that complete recovery will generally occur rapidly with no
further complications if the illness is not too severe. In
addition, pulmonary damage may be incurred as a result of the
exposure. Whether or not there is permanent pulmonary damage
has been debated for many years in the literature. A summary
of some of the reported studies and views are presented in
the following paragraphs.
Berghoff,12 after reviewing in 1919 the record of
2,000 men exposed to war gases, concluded that half of these
men had evidence of emphysema or bronchitis, but he felt that
they would regain normal respiratory functions. In contrast,
Sandall,1^5 who studied 83 gassed British pensioners, and
Hankin and Klotz,49 who studied 166 American veterans hospita-
lized from gassing, concluded in 1922 that the lung damage
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8
would result in permanent disability. Pearce91 found in 1920
that a person exposed to chlorine gas showed clinical evidence
of obstructed airways and emphysema, 12 months after exposure.
Gilchrist and Matz in 1933 found that some veterans with a
history of chlorine expo.sure had bronchitis and emphysema,
or both; five had coexistent tuberculosis, which these authors
felt was related to the chlorine gas exposure. However, the
general attitude prevailing today is similar to that expressed
by Penington in 1954.93 He concluded, citing the earlier
7ft
study (1938) of Price for support, that comparatively few
victims of war gas suffered permanent pulmonary injury.
Jones^ in 1952 conducted follow-up studies of 820
industrial cases of chlorine poisoning and concluded that
there was no clinical or radiological evidence of permanent
lung damage. In earlier studies (1923), Haggard48 suggested
that permanent pulmonary damage and disability resulting from
toxic gas inhalation might be undetectable by routine clinical
and radiological studies.
f. -3
Kowitz et al. in 1967 studied 59 persons exposed to
chlorine gas from a 1961 accident (see Section 2.1.5).
These people were examined for 2 to 3 years after the accident.
It was found that a decrease in diffusing capacity of the
lungs had resulted from the exposure. Several of the subjects
had mean respiratory function changes comparable to alveolo-
capillary injury. Even after 2 to 3 years, a decrease in lung
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volume and diffusing capacity remained. It was concluded by
the authors that the chronic effects of chlorine poisoning are
not clearly understood and, on the basis of cited animal
studies, they suggested that clinically undetectable damage
may result from exposures to chlorine gas or other gases.
Wells et al. examined 12 persons exposed to chlorine
as a result of the 1961 tank car accident described by Joyner
58
and Durel in 1962 (see Section 2.1.5). These persons were
examined for pulmonary function 3 years and/or 7 years after
the acute exposure. Measurements included tests of residual
volume, total lung capacity, pulmonary diffusing capacity,
and vital capacity. The authors concluded that "No appreciable
physiologic disorders were detected that could not be explained
by associated clinical studies."
2.1.3 Sensory Thresholds
A frequently cited reference gives approximately 10,000
39
|ag/m3 as the odor threshold for chlorine. However, more
recent studies indicate the threshold to be much lower. These
results indicate that the odor threshold is below 1,000 |jg/m3 ,
as shown by a summary of some of the published data which pro-
11 119 120 114
pose values of 150, 750, 800, and 940 (_ig/m3 .
11 94
Beck, as cited in another paper, found that odor threshold
values are higher if the emission of the gas takes place very
gradually.
120
Takhirov studied sensory thresholds for the eye re-
flex and "respiratory movement." The results indicate that
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10
the threshold for chlorine effect on eye sensitivity to
light was the same as for the odor threshold: namely, 800
iag/m3 . However, in optical chronaxy studies, a concentration
level of 1,500 |jg/m3 of chlorine was necessary to elicit a
reflex response. This was also found to be the case with
reflex activity changes in the rhythm and amplitude of
"respiratory movements."
2.1.4 Synergistic Effects
112
Stayzhkin in 1962 cited the study of Shtessel, who
investigated the combined effect on animals of chlorine and
sulfur anhydride as well as of chlorine and nitrogen oxides.
He initially established the lethal dose for cats and mice
for each of these gases separately, and then the lethal dose
for certain combinations of these gases. The results indicated
that inhalation of chlorine and nitrogen oxides in lethal doses
produces similar effects as found when administered separately.
However, when concentrations of chlorine and of sulfur anhydride that
usually produce lethal effects were combined, the results were
weaker than when either concentration was given alone; this
suggested a slight antagonistic action of the combination.
112
Stayzhkin investigated the effect of chlorine and
hydrogen chloride gas mixtures on man. In his study of the
odor threshold, the effect on reflex reactions of eye sensi-
tivity to light and of optical chronaxy were examined. His
results indicated that the two gases acted in combination
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11
(in an additive manner) to produce a perceivable odor when
neither gas could be detected alone. The effect is expressed
by the following relationship where X must equal one or
greater to have a perceivable odor:
_ Concentration Cl» Concentration HC1
Odor threshold C19 Odor threshold HC1
^
Furthermore, the physiological and neurological effects of
the mixtures were also additive.
2.1.5 Chlorine Gas Exposure to Communities Through Accidents
In March 1961, while a freighter was unloading supposedly
empty liquid chlorine cylinders in the harbor of Baltimore,
the main valve of a cylinder that was being hoisted from the
ship's hold snapped off.63 No data were given regarding the
amount of chlorine that was in the cylinder before it ruptured.
As a result of this accident, 156 persons were examined at
three hospitals and 37 were given further treatment. Several
men returned to the hospital within 48 hours and were sub-
sequently admitted for treatment. Of the 17 persons admitted
at one hospital, 11 had respiratory distress: four, hemoptysis;
eight, rales; six, wheezes or rhonchi, or both; and four,
edema or infiltrate. One of these patients developed bacterial
pneumonia. A follow-up examination of these 17 patients was
given at 30 to 60 days, 6 months, and 14 months, as well as 2
to 3 years after the accident. It was found that 19 to 35
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12
months after the exposure, the victims generally complained
of shortness of breath and fatigue on exertion. Other symp-
toms noted, in order of descending frequency, were: cough,
nonspecific chest pain, frequent headaches, dryness of the
oropharyngeal membranes,-decreased stamina, and muscular
weakness. Eleven of the 17 victims had mean respiratory
function changes comparable with those resulting from an
alveolocapillary injury. During the 2 to 3 years of the
survey, continuing repair with increased airway resistance
was noted. A decrease in lung volume and diffusion capacity
remained after the completion of the survey. An additional
study of 59 of the 156 persons exposed to the chlorine, in-
cluding the 11 mentioned above, was made 11 to 20 months after
the accident. The conclusion from this follow-up study was
that a decrease in vital capacity, decreased pulmonary elas-
ticity, and a decrease in diffusion capacity resulted from
the exposure to chlorine.
In January 1961, a tank car was derailed at the rural
community of La Barre, La., spilling 6,000 gallons (36 tons)
of liquid chlorine. The cloud of chlorine gas that formed
covered approximately 6 square miles, necessitating the evac-
uation of some 1,000 people. Air samples taken in the area
7 hours later showed that chlorine concentration ranged from
1,200,000 fag/m3 (400 ppm) 75 yards from the site of the acci-
dent to 30,000 |ag/m3 (10 ppm) in the fringe areas of the cloud.
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13
Approximately 100 people were treated for varying degrees of
chlorine exposure, and an 11-month-old infant died as a result
of the exposure to chlorine. Of the 65 persons checked at
one hospital, 15 were admitted for further treatment. Patients
complained of burning eyes and evidenced acute conJunetival
infection with lacrimation and photophobia. Those persons
heavily exposed experienced severe dyspnea, coughing, retch-
ing, and vomiting. Increased body temperatures (reaching
101°F), anorexia, and moist rales were common. Of the origi-
nal 15 persons admitted to the hospital, 10 developed unmistak-
able pulmonary edema. By the 16th day after admittance, all
the patients had been discharged. In addition to the humans
affected, many domestic and commercial animals located within
1^ miles downwind of the accident were killed.
In 1947 in Brooklyn, N.Y., gas escaped near a subway
ventilator grating after a 100-pound tank of liquid chlorine
developed a 1/8-inch hole. The people in the area were ex-
posed for approximately 17 minutes before the chlorine emissions
could be stopped. Those exposed were overcome by choking,
nausea, vomiting, anxiety, and syncope. Some were lying pros-
trate in the street, while many others demonstrated distress
and weakness. People with mild exposures mainly exhibited
burning of eyes and nose, lacrimation, and rhinorrhea. Of
the 418 people examined, 208 were admitted to hospitals for
treatment. At one hospital all of the 33 patients treated had
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14
varying degrees of tracheobronchitis; 14 developed pneumonia,
and 23 developed pulmonary edema. After hospitalization,
further observations were made of 29 of the patients. Six-
teen of these showed anxiety reactions with phobias, hys-
terical phenomena, and psychosomatic dysfunction for periods
lasting from 1 to 16 months. However, none of the 29 patients
developed permanent pulmonary disease.
2.2 Effects on Animals
2.2.1 Commercial and Domestic Animals
No information has been found in the literature per-
taining to injury of domestic, commercial, or wild animals
as a result of exposure to chlorine gas either in ambient
air or near plants that produce or use chlorine. Several
animals including dogs, cats, horses, mules, chickens, hogs,
cows, and ducks died as a result of an accidental spillage
58
of chlorine in La Barre, La. (see discussion in Section
2.1.5).
2.2.2 Experimental Animals
Numerous animal studies on the effects of chlorine have
been reported and are summarized in Table 4 in the Appendix.
The results of several reports have been discussed in Section
2.1. Autopsy data on mice and rats exposed to chlorine con-
centrations of approximately 3,000,000, 750,000, and 189,000
|jg/m3 are given in Table 5 in the Appendix. These autopsies
1 indicate that the rats showed much edema and slight to
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15
moderate hemorrhage of the lungs, after exposure, whereas
the mice showed somewhat less edema and more hemorrhage.
Furthermore, chlorine appears to produce greater amounts of
lung hemorrhage and edema than the same concentrations of
ammonia, hydrogen cyanide, sulfur dioxide, and hydrogen sul-
fide.
2.3 Effects on Plants
2.3.1 Phytotoxicity
13
Brennan, Leone, and Daines studied the effects of
various concentrations, 300 to 4,500 ng/m3 (0.1 to 1.5 ppm)
of chlorine gas on 26 different species of plants. The most
common symptoms of chlorine poisoning were necrosis and
bleaching of the foliage, which occurred within a day or two
after the chlorine exposure. Bleaching of the leaves was a
typical symptom which developed from exposure to low concen-
trations of chlorine. Such species as spinach and cucumber
had a bleaching pattern similar to that produced by ozone.
In respect to necrotic tissue, the leaf color ranged from
white to tan to brown. Generally, the necrotic area was
marginal and ihterveinal. However, there are many exceptions:
for example, tomato, tobacco, radish, and cucumber had necrotic
areas scattered over the leaf blade, while alfalfa in some
cases had necrosis only of the veins. The oldest and the
middle-aged leaves appeared to be more susceptible to chlo-
rine injuries than the younger leaves. Furthermore, the
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16
cotyledons showed greater resistance to injury than the mature
primary leaves. The upper leaf surface appeared more sensi-
tive to chlorine gas than the bottom, although injury occurred
on both sides.
1 "57 1 "38
Zimmerman ' found similar responses in 16 species
of plants exposed to chlorine concentrations of 1,380 to
14,010 |_ig/m3 (0.46 to 4.67 ppm). The most characteristic
symptom was spotting of the leaves similar to that observed
with sulfur dioxide. The spots initially appeared as cooked
areas that turned straw-yellow or brown within a few days.
Leaf fall was associated with moderate to severe injury.
Other symptoms also found include epinasty of tomato
leaves at chlorine concentrations insufficient to produce
1 "3
spots, and "cupping" of the younger leaves of squash. In
some species, e.g. sugar beets, the upper epidermis may be
121
injured, giving it a detached "silver-leaf" appearance.
It was reported that leaf fall may occur without the
113
evidence of symptoms.
39
Heck et al. exposed plants to 62 ppm of chlorine, and
noted that squash, soybean, and cowpea plants showed a loss of
turgor in addition to the necrosis. After exposing tomato,
buckwheat, and tobacco to chlorine concentrations of 3,000
TOO
ug/m3 (1,000 ppm), Thornton and Setterstron observed that
the stem tissue was bleached and had a cooked appearance.
2.3.2 Sensitivity of Plants
The sensitivity to chlorine gas varies greatly among
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17
TO 1 Op
different species of plants. ' Some of the most suscep-
tible to injury from chlorine gas include radish, alfalfa,
peach, coleus, cosmos, buckwheat, and tea rose. Species that
have a high resistance include Chinese holly, eggplant,
tobacco, Werech enopodium, polygonum, oxalis, begonia, and
pepper. Table 6 in the Appendix summarizes the effects of
chlorine gas on various plants as reported in the literature.
123
Thornton and Setterstrom compared the toxicity of
five gases and concluded the relative toxicity to green plants
137
as C10>SO >NH,i>HCN>H0S. Zimmerman arrived at a similar
2. 2 ^" ^
13
conclusion, namely: HF>Cl2>SO2>NH3>H2S. Brennan et al.
agree that chlorine is a stronger phytotoxicant than sulfur
79
dioxide. McCallan and Setterstrom reported the same re-
123
suits as Thornton and Setterstrom. Moreover, they compared
the overall effect of chlorine on other organisms and concluded
that the order of toxicity susceptibility was as follows:
leaves>fungi, bacteria, stems, animals>seeds and sclerotia.
2.3.3 Effect of Moisture
Tomato plants were exposed to chlorine concentrations
of 930, 1,830, and 4,140 |ag/m3 for 2 hours. During the ex-
posure some plants were periodically sprayed with water, whereas
others were not. When the plants sprayed with water and those
left unsprayed were compared, no difference was found in the
degree of injury resulting from the exposure to chlorine.
Barton investigated the effects of chlorine gas at
concentrations of 750,000 and 3,000,000 |jg/m3 (250 ppm and
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18
1,000 ppm) on the germination of dry and soaked radish and
rye seeds. Dry radish seeds did not appear to be affected
by a-960-miriute exposure at either concentration level.
However, after 960 minutes of exposure to 3,000 [jg/m3 (1,000
ppm) chlorine, the soaked seeds showed approximately 90 per-
cent less germination, and approximately 16 percent less at
750,000 |jg/m3 (250 ppm) chlorine. Germination of the dry rye
seeds showed a reduction of approximately 50 percent at the
higher chlorine concentration for 960 minutes, while only
slight reduction (approximately 10 percent) at the lower con-
centration. The soaked rye seeds started to show a reduction
in germination at 240 minutes when exposed to 750,000 |jg/m3
(250 ppm) chlorine, and at 60 minutes with 3,000,000 |-ig/m3
(1,000 ppm). When exposed for 960 minutes, there was a 68
percent reduction at the lower concentration, whereas at the
higher concentration there was no germination at all.
2.3.4 Effect of Light
Experiments were performed to determine the effect of
light on the response of tomato plants to chlorine gas.
Plants kept in the dark for 20 hours prior to fumigation with
1,800 |ag/m3 (0.60 ppm) of chlorine for 2 hours were injured
to the same extent as plants kept under the usual greenhouse
conditions prior to similar exposure. However, plants kept
in the dark for 20 hours after the exposure to chlorine had
50 percent less damage than those plants treated under similar
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19
conditions, but kept in the daylight in a greenhouse after
exposure.
1 p*3
Thornton and Setterstrom compared the effect of
clear as compared to cloudy weather. Tomato plants were
exposed to chlorine concentrations ranging from 1,200 to
3,000,000 |_ig/m3 (4 to 1,000 ppm) for periods of as long as
2 hours. The results indicated that the injury to the leaf
tissue occurs in a shorter period of time on a clear day than
on a cloudy day, particularly at low concentrations of chlo-
rine.
2.3.5 Effect of Water Stress
13
Brennan, Leone, and Daines investigated the effect
of water stress on tomato plants exposed to a chlorine con-
centration of 1,800 t-ig/m3 (0.60 ppm) for 2 hours. The turgid
plants had necrotic injury on both the oldest and the middle-
aged leaves, while only 25 percent of the wilted plants that
were tested developed injury, which was slight. Spraying of
the plants with N-dimethylamine to close the stomata also
reduced the injury from chlorine, but not as effectively as
the reduction produced by wilting.
1 OQ
Zimmerman similarly showed that wilted plants have
a pronounced resistance to chlorine as compared with turgid
plants.
2.3.6 Plant Accumulations
Brennan et al. investigated the relationship between
degree of tomato plant injury and the chloride content of the
leaves. Tomato plants were fumigated with 1,200 |-ig/m3 of
-------
20
chlorine (0.40ppm) for 6 hours, which caused no visible foliage
injury; chlorine concentration of 1,800 M.g/m3 (0.60 ppm) for
4 hours, which caused moderate injury; and concentrations of
5,200 |jg/m3 (1.40 ppm), which caused severe injury. Analy-
sis of the leaves indicated that the chloride content of the
tissue did not correlate either with the level of chlorine
exposure nor with the amount of injury to the plant. To sub-
stantiate these results the chloride content of the leaves
(top and lower), stems (top and lower), and petioles (top
and lower) were analyzed before and after exposure to 1,800
M.g/m3 (0.60 ppm) of chlorine for 3 hours. The chloride dis-
tribution of these six fractions did not appear to significantly
change from an analysis made immediately after exposure to an
analysis made 1 day later. Hence, it was concluded that chlo-
ride analysis of plants cannot be used as a method of diagnosing
injury that results from chlorine gas exposure.
72
However, Liegel and Oelschlager observed an increase
in the chlorine content of lettuce and spinach plants after
fumigation with chlorine gas. Sufficient data were not given
(e.g., the chlorine concentration used) to compare their results
with those of other studies.
An incident occurred in which silver maple trees were
damaged as a result of emissions (from a glass manufacturing
company) containing both hydrogen chloride and some chlorine.
Analysis indicated a slight increase in chloride in exposed
-------
21
maples as compared to uninjured maples.
A study of the effects of gases on the pH of the
leaves and stems of tomato plants was reported by Thornton
123
and Setterstrom. Chlorine was found to be more effective
in lowering the pH of the leaves than was ammonia, sulfur
dioxide, hydrogen cyanide, or hydrogen sulfide. Plants ex-
posed for 15 minutes to chlorine concentrations of 12,000
|-ig/m3 (4 ppm) reduced the pH by 0.3 units, while 960 minutes
at the same concentration reduced the pH by 1.0. After 960
minutes at 3,000 |ag/m3 (1 ppm) chlorine, the pH was lowered
by 0.2; at 48,000 |jg/m3 (16 ppm), by 1.6; at 189,000 fag/m3
(63 ppm), by 4.7; at 750,000 |_ig/m3 (250 ppm), by 4.5; and at
3,000,000 iag/m3 (1,000 ppm), by 5.5. In contrast, the pH of
the stem exhibited little change; at 3,000,000 (ag/m3 (1,000
ppm) of chlorine for 960 minutes, the pH was lower by only
1.0 unit. Additional tests indicated that the older and lower-
most leaves showed the greatest pH change, while pH change
of the stems was uniform from top to bottom. Furthermore,
it was also found that the effectiveness of chlorine in
lowering the pH was much greater in sunlight than in darkness.
Thus, exposure to 3,000,000 (-ig/rn3 (1,000 ppm) of chlorine
for 4 minutes decreased the pH in the leaf tissues by approxi-
mately 2.8 units in sunlight, but only approximately 0.3 units
in darkness. Under the same conditions, the pH of the stems
was reduced by approximately 0.2 units in sunlight and approxi-
mately 0.05 units in darkness.
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22
The results of these studies suggest that the amount
of plant injury was positively correlated with the effective-
ness of chlorine (as well as of sulfur dioxide, ammonia, and
hydrogen sulfide) in causing a change in pH.
2.3.7 Episodes of Plant Damage
Several cases have been reported in the literature in
which plants have been injured as a result of accidental chlo-
rine leaks around sewage treatment plants, factories, and even
. . . 53,86,106,116,137,138 „ .. .
swimming pools. However, no chlorine
air measurements were given in these reports.
116
Stout in 1932 reported an instance in which lettuce
and weeds growing near a sewage treatment site in California
were injured as a result of a chlorine leak from the sewage
chlorinating apparatus.
138
Zimmerman ' later reported two such incidents in
the vicinity of Yonkers, N.Y. One occurred near a swimming
podl as a result of a leak from a cylinder of chlorine which
was used to purify the water. The other involved the acci-
dental emission of chlorine gas from a factory. As a conse-
quence of these two episodes, some 30 species of plants were
injured, including Ailanthus sp. , apply (Malus) , cherry
(Prunus sp.), maple (Acer sp.), smartweed (Polygonum sp.),
Weigela sp., basswood (Tilia americana L.), dogwood (Cornus
sp.), elm (Ulmus sp.), ash ( Fraximus sp.), sweet gum (Liquid-
ambar sp.), hemlock (Tsuga sp.), oak (Quercus sp.), and white
pine (Pinus alba).
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23
106
Schmidt reported that an accident with chlorine
caused defoliation of peach, apple, and quince trees.
53
Hindawi mentioned an accidental chlorine release
from an industrial plant in a residential area in Cincinnati,
Ohio. One day after the accident, leaves began to fall from
tomato plants and trees in the area, and the silver maple
trees showed marks similar to those caused by sulfur dioxide.
Furthermore, privet hedges in the area were nearly bare.
Emissions from a glass manufacturing factory in another
region injured shrubs, trees, and ornamental plants in the
surrounding area. Specimens which were severely injured
included maple, cherry, rose (both bud and bush), and begonia.
Factory stack emissions analyzed after the episode contained
119 to 473 ppm of hydrochloric acid and 0.52 to 0.92 ppm of
chlorine. Analysis of injured silver maples showed 4,700
ppm chloride compared to 3,800 ppm for the uninjured trees.
2.4 Effects on Materials
Examples in which chlorine gas has caused economic
damage to material have not been discussed in the literature
reviewed. However, the high reactiveness of chlorine with
almost all metals (including iron, zinc, tin, silver, and
copper) as well as with nonmetals (including most organic
compounds) suggests that chlorine in sufficiently high con-
centrations would corrode metals, discolor and damage painted
materials, and damage textile fibers.
-------
24
20
Chiarenzelli and Joba studied the corrosion of
different metals in areas which have significant levels
of atmospheric pollution. At one site, a heavy and unique
tarnish film that was noted on silver was thought to be a
result of the high chlorine concentrations in that area.
2.5 Environmental Air Standards
The American Conference of Governmental Industrial
Hygienists (ACGIH) has adopted an 8-hour threshold limit value
124
(TLV) for chlorine of 3,000 ng/m3 (1 ppm). This TLV is
based on data which indicate that men can work at this concen-
tration of chlorine without interruption from eye, nose, and
throat irritation.
West Germany has established the same TLV for working
conditions as the United States (3,000 ug/m3 or 1 ppm).94 The
West Germany Verein Deutscher Ingineure (VDI) Committee on
Air Purification in 1960 established a chlorine "continuous
exposure value" of 300 [ag/m3 (0.1 ppm) as a mean value for
94
30 minutes. It is permissible to exceed this value, but
for no more than three times in one day and by no higher than
a 30-minute mean chlorine value of 1,500 |ag/m3 (0.5 ppm).
Russia has established a 24-hour average maximum
allowable concentration of 30 |jg/m3 (0.01 ppm) of air for
Vft
chlorine. A single measurement should not exceed 100 |ag/m3
(0.033 ppm). Russia's maximum 8-hour occupational exposure
for chlorine is 1,000 |ag/m3 (0.33 ppm), or one-third that
adopted by the ACGIH.
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25
3. SOURCES
3.1 Natural Occurrence
Natural occurrences of free chlorine gas are extremely
rare, due to the high reactivity of chlorine with many sub-
stances. Volcanic gases- contain very small amounts of chlorine
22
gas. Low concentrations of chlorine may, however, Jbe formed
y
by atmospheric reactions. For example, chloride compounds
and nitrogen dioxide may react to form nitrosyl chloride,
which can decompose photochemically to yield free chlorine.
Also, chlorides in the presence of strong oxidants (such as
ozone) may be oxidized to chlorine.
3.2 Production Sources
The ever-increasing demand for chlorine has resulted
in a doubling of production in the last 10 years (see Table 7
in the Appendix)- In 1967, the production was approximately
29
7.65 million short tons. The projected production for 1971
is 10 million short tons, assuming a rate of increase in pro-
duction of 7 percent per year, which is simil.i?r to the rate of
23
the past 10 years.
The major processes for the production of chlorine in
the United States are the electrolysis of aqueous alkali
chloride via the diaphragm cell or mercury cell, and to a
lesser extent, fusion electrolysis of alkali chlorides (Down
Process), and the nitric acid process. Diaphragm - and
- cell processes accounted for over 95 percent of
-------
26
the chlorine produced in 1964. A more detailed description
of these processes can tie found in several reference
5,22,75,108,115
sources.
There were 69 plants producing chlorine in the United
21
States in 1964. A list of the major producers is given in
Table 8 in the Appendix. A more detailed list is to be published
of producers in the United States, giving the type of process
used, nominal capacity, and location.
The major sources of atmospheric emissions of chlorine
from the production processes are the following: liquefication
processes, the filling of containers or transfer of liquid
chlorine from one container to another, the cleaning of re-
turned tank cars containing residual chlorine, the improper
treating of spent brine solution and of "sniff" or "blow"
gas (the gas remaining after the final liquefication step),
and occasional equipment failure (for example, a chlorine
.11,15
compressor breakdown).
3.2.1 Electrolytic Diaphragm Cells
Electrolytic diaphragm cells account for over two-thirds
of the chlorine production. In this process, a saturated
aqueous solution of sodium chloride or potassium chloride is
electrolyzed. Chlorine gas (98 percent chlorine) is liberated
at the anode, while alkali solution, as well as some by-product
5, 75
hydrogen gas, is liberated at the cathode. ' The chlorine
gas leaves the cell and is passed through coolers. The chlorine-
-------
27
saturated water that condenses in the coolers passes to the
sewer through a limestone pit and is not considered to be a
source of air pollution. The partly dried chlorine gas
from the coolers is further dried by contact with sulfuric
acid. The spent sulfuric acid is either reclaimed or dis-
charged to the sewer after neutralization.
The dried chlorine gas can be used directly, but it is
more common to liquefy the gas by compression and cooling.
The gas residue after the final liquefication process, called
"sniff gas," "blow gas," "vent gas," or "tail gas," consists
of air and chlorine. This mixture normally consists of about
20 to 50 percent chlorine, or as much as 8 percent of the
119
plant's total chlorine production. Thus, if the sniff gas
were allowed to be directly vented to the atmosphere, 1 to
6 tons of chlorine would be emitted for every 125 tons produced.
The filling of tank cars, barges, and other containers
with liquid chlorine can result in a loss of 2 percent of the
42
chlorine production. In many plants, this vent gas is col-
lected and piped either for direct use without further purifi-
cation, or to recovery systems. The sniff gas is used by
other in-plant processes (such as preparation of bleaching
solution and chlorination of organic compounds), or is treated
further by either scrubbing or absorption methods to remove
the chlorine (see Section 4). In most cases, the chlorine can
be recovered economically by means of these purification methods,
-------
28
3.2.2 Electrolytic Mercury Cells
Electrolytic mercury cells account for about one-
fourth of the total chlorine production. To produce these
cells, solution of sodium or potassium chloride is electro-
lyzed. Chlorine gas collects at the anode, while at the
mercury cathode sodium or potassium metal is produced, which
forms an amalgam with the mercury- The amalgam is then
reacted with water in another section to yield alkali hydrox-
ide and hydrogen gas. The advantage of this process over
the other electrolytic processes is the high purity of alkali
hydroxide which is produced.
The drying, liquefication, and collection of the chlo-
rine gas is similar to that discussed for the diaphragm-cell
process.
3.2.3 Fusion Electrolysis of Chloride Salts
The fusion electrolysis of chloride salt accounts for
less than 5 percent of the total chlorine production. This
method is primarily used to prepare pure metals, namely mag-
nesium and sodium metal, from their chloride salts. The
co-product—chlorine gas—is collected at the anode and
further processed by a method similar to that described for
the diaphragm-cell process.
3.2.4 Other Processes
Other processes that have been used for making chlorine
gas include (1) treatment of sodium chloride with nitric acid,
-------
29
(2) electrolysis of hydrochloric acid, and (3) oxidation of
hydrochloric acid with catalyzers.75'" Of these, only the
first is of importance in the United States, but even so, this
process accounts for less than 1 percent of the present United
States production.
3.3 Product Sources
The largest consumer of chlorine is the chemical
industry* which uses this substance for the manufacture or
preparation of chemical compounds—both organic and inorganic.
Nearly 80 percent of the total chlorine production of this
country is consumed in this way, with the organic compounds
accounting for the greater part—approximately 70 percent
of the total production. The second largest user is the
pulp and paper industry (which consumes .approximately 16
percent of total production), followed by water and sewage
treatment (approximately 4 percent of total production).
Table 9 in the Appendix gives the consumption of chlorine by
uses for 1963 and 1964.
3.3.1 Chlorinated Organic Chemicals
The manufacturing of chlorinated organic chemicals
constitutes the largest use of chlorine by the chemical
industry. Uses include the preparation of:
Solvents; trichloroethylene, perchloroethylene,
methylene chloride, and carbon tetrachloride;
Plastics and fibers; vinyl chloride and vinylidene
chloride;
-------
30
Pesticides and herbicides: DDT (dichloro-diphenyl-
trichloro-ethane), benzene hexachloride, and toxaphene;
Refrigerants and propellants: freons and genetrons.
3.3.2 Other Organic Chemicals
Several chemicals are prepared via chlorination (dry
or in the presence of water), followed by dehalogenation,
to yield compounds that contain no chlorine, even though
chlorine is used in their manufacture. These chemicals in-
clude ethylene glycols, glycerine, ethylene oxide tetraethyl
and tetramethyl, lead additives, cellophane, Pharmaceuticals,
and detergents.
3.3.3 Inorganic Chemicals
A large variety of inorganic chemicals are made by
using chlorine, including chloride salts (ammonium, calcium,
and ferric chlorides, etc.), metals (e.g., aluminum), and other
compounds (bromine, boric acid, paint coatings, silicates,
phosphates, etc. ).
3.3.4 Other Uses
A large amount of chlorine is being used by the pulp
and paper industry, particularly for the oxidation of the
odorous sulfur compounds present in the black liquor and in
25 133
the bleaching operation. ' The amount of chlorine needed
to oxidize the sulfur compounds depends on the pH of the
solution and the amount and type of sulfur compounds present.
For example, to completely oxidize a mole of mercaptan in
-------
31
neutral or acid conditions requires between 2.4 to 3.3 moles
of chlorine, While under basic conditions, only 1.5 to 2.6
moles of chlorine are required. Sulfides require 2 to 3.4
moles of chlorine per mole of sulfide, depending on the con-
ditions of the oxidation, while a mole of disulfide requires
about 5.2 moles of chlorine.
Other uses include the production of compounds for
household bleaches as well as for textile bleaching and
finishing, water and sewage treatment, petroleum production
and refining, rubber reclaiming, and food processes.
3.4 Environmental Air Concentrations
No information has been found on the environmental
air concentrations of chlorine gas.
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32
4. ABATEMENT
In plants producing chlorine gas, the electrolytic
cells, the chlorine coolers, and the drying systems are
operated at a slight vacuum, which normally prevents the
emission of chlorine from these systems. In spite of this
precaution, an upset or malfunction of the pumps or a large
leak in the system may cause a temporary discharge of chlorine
to the atmosphere.
The major source of chlorine emissions, however, is
the presence of residual gases remaining after the liquefi-
cation of the chlorine cell gas. These residual gases may
contain from 20 to 50 percent chlorine by volume, depending on
the conditions of liquefication. Other sources of emission
include the loading and cleaning of tank cars, barges, or
cylinders; dechlorination of spent brine solutions; and power
5,75,115
or equipment failures. To prevent air pollution from
these sources, the emissions from these systems can often be
piped to the sniff gas system or tied in directly either to
a scrubber system or a high stack for dispersion. When scrub-
bers are used, the effluent from the scrubber is vented to a
tall stack.
Several efficient methods have been developed to con-
5 99 115
trol chlorine emissions. ' ' The most common of these
methods include the use of liquid scrubbers which employ either
water,14'42'55 alkali solutions, ' carbon tetrachloride,
-------
33
87,119,42 . . . 4_. 51 , t , _ ^
or brine solution, as well as solid absorbents
134
such as silica gel. With the exception of the alkali
solution technique, all these methods can be used to recover
the chlorine. Other control methods which have been reported
use sulfur dichloride, hexachlorobutadiene, and stannic
chloride.
Some producers send the untreated emission gases con-
taining chlorine to other in-plant operations, where they are
used directly, for such operations as chlorination of hydro-
carbons .
4.1 Water Scrubbers
When controlled by water scrubbers, the chlorine-
containing vent gas is passed countercurrently to a water
stream in a tower filled with ceramic packing. Upon treatment
with a water scrubber, a vent gas initially containing 15 per-
cent chlorine by volume yields an effluent gas containing
15,000,000 to 30,000,000 iag/m3 (5,000 to 10,000 ppm) of chlo-
14
rine. It is common practice to pass gases from the water
scrubber through the more efficient alkali scrubbers, or to
tall stacks for dispersion. The chlorine-rich scrubber solu-
tion is heated so that the chlorine may be stripped and re-
covered . An alternate method of treatment of the chlorine-
rich water is to pass the water over activated charcoal or
iron filings. The result is an oxidation-reduction reaction
that converts the chlorine to the noninjurious chloride ion.
-------
34
4.2 Alkali Scrubbers
Contact of chlorine with alkali solutions (usually
caustic or lime solutions) produces an effluent gas with a
lower residual chlorine concentration (often below the odor
threshold of about 1 ppm) than can readily be attained by
5
water scrubbing. The reaction products are bleach, salt, and
water. The main disadvantage of this method is the cost as
well as the difficulty of disposing of the bleach solution
(hypochlorite). This bleach solution is sometimes reused by
local plants (such as pulp and paper industries), or can be
treated with carbon to reduce the chlorine to chloride ion.
However, some producers dispose of the solution by dumping
it in rivers and streams.
4.3 Carbon Tetrachloride Scrubbers
The advantage of using carbon tetrachloride as an ab-
sorbent is that its absorbing capacity for chlorine gas is 10
to 12 times greater than water, and the recovery of the chlo-
rine much more complete. However, losses of carbon tetra-
chloride have been reported as high as 30 pounds per ton of
87
recovered chlorine.
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35
5. ECONOMICS
No information has been found on the economic costs
of chlorine air pollution. Localized accidental emissions
of chlorine could have an economic impact due to injury or
death of humans, animals,- and plants. Several instances of
such episodes have been reported.
No information was found on the costs for abatement
of chlorine air pollution. However, many companies recover
the chlorine from gas streams for reuse or sale.
The production and consumption of chlorine have been
discussed in Section 3. The production is expected to con-
tinue to increase for the next few years at the current rate
of 7 percent. If this rate continues for 10 years, the pro-
duction will double by 1978.
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36
6. METHODS OF ANALYSIS
There appears to be no specific method for the analysis
of chlorine. Most of the methods used rely on the oxidizing
property of chlorine , and thus the presence of other oxidizing
agents—such as ozone, bromine, nitrogen oxides, sulfur oxides,
etc.—can sometimes seriously interfere with the analysis.
6.1 Sampling Methods
Chlorine gas samples are collected either in impingers
containing a reactive liquid solution or on a solid which is
impregnated with a reactive substance.
The common liquid solution used in the United States
is dilute sodium hydroxide solution (approximately 0.01 to
0.1 N). ' This basic solution converts the chlorine gas
to equal amounts of chloride ions and hypochlorite ions.
When the solution is made acidic, the reaction is reversed
and the chlorine gas is regenerated. However, the hypochlorite
ion can further slowly decompose (under basic conditions) to
give more chloride ions and oxygen. The amount of hypochlorite
ion that decomposes will result in a corresponding loss in
chlorine gas when the solution is acidified.
Other common absorber solutions react with chlorine
gas to directly or indirectly produce a color change in the
solution, which is taken as an indication of the amount of
chlorine in the sampled air or gas. A variety of solutions
are used, which are discussed in the following sections.
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37
The chlorine gas can also be absorbed on solids con-
taining reactive substances similar to those used with the
absorber solutions. A color change results which indicates
the amount of chlorine that is present. The solid support
is usually either paper or silica gel. The former is generally
used for both qualitative and quantitative measurements, while
the latter—found in the commercially available "detector
tubes"—is usually reserved for quantitative measurement.
Some of the reactive substances are discussed in the following
section.
6.2 Qualitative and Semiquantitative Methods
Many types of chlorine-indicator papers have been
described in the literature. Among the most common are the
Af> fi^ Q4 1 99
starch-iodide papers. ''' The basic reaction of
chlorine gas with the potassium iodide of the paper yields
free iodine, which then reacts with the starch to produce a
blue color. (However, other oxidants can also turn the paper
blue.) The limit of detection is approximately 2 to 6 ppm.
A starch-iodide paper also coated with glycerin and sulfurous
acid is reported to turn brown or black and to have a sensi-
tivity of 0.25 to 12 ppm. A buffered cadmium-iodide-starch
paper is reported to be free of interference from nitric oxide.
Other common papers used include bromide-fluorescein
papers,46'67'69'13 which change from yellow to red or rose,
with a sensitivity of approximately 10 ppm; and o-tolidine
-------
38
papers, ' ' ' which turn yellow or bluish green (de-
pending on other reagents present), with a sensitivity of
approximately 2 ppm. Other indicator papers that have
been reported include dimethylaniline,129 aniline,27'46'71'135
, ^.,. 88 , , . ,. 102
o-phenetidine, and benzidine.
Rapid semi-quantitative determination of chlorine
gas can be made with commercially available gas-detecting
tubes. ' ' These tubes contain a solid-coated reactive
material which changes colorimetrically when exposed to a
specific gas or to certain types of gases. A given volume
of the gas sample is passed over the absorbent, and the
amount of absorbent that changes color (measured by the
length that is affected) is used to determine the amount of
particular gas being tested (in this case, chlorine gas).
Reactive substances that have been used as indicators for
62 30 37
chlorine are o-tolidine, bromide-fluorescein, ' and
80
tetraphenyIbenzidine.
Continuous sampling instruments for detection of chlo-
rine gas have been developed, based on the reflectance from a
chlorine-sensitive coated paper. ' ' An alarm system can
be used with the instruments to warn when a certain limit has
been reached. Sensitivity ranges from 300 to 9,000 |-ig/m3
(0.1 to 3 ppm) of chlorine.
6.3 Quantitative Methods
Most quantitative methods of analysis for chlorine gas
are based on colorimetric reactions. A sensitive reagent
-------
39
commonly used is o-tolidine.44'84'92'97'114'128 The air
sample can either be passed directly into an acid solution
of o-tolidine or collected in dilute sodium hydroxide, which
can later be acidified and the o-tolidine then added. The
latter method has the advantage that the time allowed for
the development of color can be controlled and maximized.
Acidification yields a more stable yellow-to-orange color.
Color comparisons can be made with standardized color solu-
tions by visual methods or in a spectrophotometer at 435 and
490 mu- Approximately 3 liters of air must be sampled to
detect chlorine concentrations of 3,000 |jg/m3 . This method
is reported to be better than 99 percent efficient. How-
ever, the presence of other oxidants—such as chlorine dioxide,
ozone, ferric and manganic compounds, and nitrates—may
interfere with this method.
85
In a new method used in England, the reagent 3,3'-
dimethylnaphthidine turns mauve in the presence of chlorine
gas. This reagent is about eight times more sensitive than
o-tolidine. Other oxidizing agents, such as bromine, chlorine
dioxide, nitrogen dioxide, etc., interfere with the test.
One reagent is reported to be specific for chlorine
gas, with a sensitivity of 1,000 fag/m3 , even in the presence
of such oxidants as bromine, ozone, and nitrogen oxide.
The method is based on the oxidation of arsenious anhydride
in an alkaline solution in the presence of potassium iodide
and starch. The solution turns blue in the presence of chlo-
rine.
-------
40
Other reagents used for determination of chlorine gas
that have been reported in the literature include: dimethyl-
p-phenylenediamine, ' methyl orange, ' ' iodide-starch,
3 iodide-starch-arsenic oxide, ' benzidine acetate,
30 34
bromide-fluorescein, resorufin, 4,4'-tetramethyldramino-
"7 *D
diphenylmethane, and rosaniline hydrochloride.
Recently an air analyzer for chlorine gas was reported,
based on polarographic measurements with a special galvanic
cell.35
-------
41
7. SUMMARY AND CONCLUSIONS
Low concentrations of chlorine gas cause irritation
of the eyes, nose, and throat of humans (approximately 3,000
[ig/m or 1 ppm is the threshold value). Excessively pro-
longed exposures to low concentrations, or exposure to
higher chlorine concentrations, may lead to lung diseases
such as pulmonary edema, pneumonitis, emphysema, or
bronchitis. Recent studies indicate that other residual
effects may occur, such as a decrease in the diffusing
capacity of the lungs. Furthermore, there is evidence
which suggests that continuous exposure to low concentra-
tions may cause premature ageing and increased suscepti-
bility to lung diseases.
Chlorine is also a phytotoxicant which is stronger
than sulfur dioxide but not as strong as hydrogen fluoride.
Several episodes have been reported in which chlorine emissions
from accidental leaks or spillages have resulted in injury
and death to humans, animals, and plants. Material damage
from chlorine is possible, since chlorine has strong corrosive
properties.
From 1958 to 1967 the production of chlorine doubled.
In 1964 there were 69 industrial plants producing chlorine.
The major production processes involve the electrolysis of
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42
alkali chloride solution. Possible sources of chlorine pollu-
tion from these processes include the liquefication process,
the filling of containers or transfer of liquid chlorine, and
the emission of residual gas from the liquefication process.
No information is currently available on the concentra-
tions of chlorine gas in ambient air. However, chlorine has
been classified and is presently analyzed as one of the
"oxidants" of the air.
Effective methods are available for controlling chlo-
rine emissions. In some cases the chlorine or its by-products
can be recovered for further use.
No information has been found on the economic costs
of chlorine air pollution or on the costs of its abatement.
Methods of analysis are are available; however they are
not sufficiently sensitive or selective for determining
atmospheric concentrations of chlorine.
Based on the material presented in this report, further
studies in the following areas are suggested:
(1) Determination of the present-day concentration of
chlorine gas in ambient air in large metropolitan areas and
near large production sources. This will involve development
of better methods of analysis for chlorine gas than those
presently available.
(2) Determination of whether chronic effects develop
from chlorine gas exposures at low concentrations on humans
and animals.
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43
(3) Determination of the effect of atmospheric chlorine
gas on plants and materials
(4) Determination of the products that result from
the reaction of chlorine gas with other substances present in
the atmosphere.
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44
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of Volatile Mineral Acids (Hydrochloric and Nitric) in the
Atmosphere, Hyq. Sanitation 31(9):440 (1966).
Gross, P., W. E. Rinehart, and R. T. P. deTreville, The
Pulmonary Reactions to Toxic Gases, Am. Ind. Hyq. Assoc. J.
18:315 (1967).
Gubar1, M. A., and N. D. Kozlova, The Determination of
Maximum Permissible Concentrations of Residual Chlorine and
Chloramine in Drinking Water, Hyg. Sanitation 31:19 (1966).
Harris, L. S., Fume Scrubbing with the Ejector Venturi System,
Chem. Eng. Progr. 62.(4):55 (1966).
Hausberg, G., and U. Kleeberg, Installations for Purification
of Waste Gases Generated During Chlorine Treatment of Light
Metal Foundry Melts, Giesserei (Dusseldorf) J53_(5):137 (1966).
Health Hazards of Military Chemicals, Army Chemical Warfare
Laboratory, Army Chemical Center, Md. (Reports published to
1 April 1959).
Hetzel, K. W., Poisonous Action and Detection of Injurious
Gases and Vapors in Mining Operations, Brennstoff-Chem. 40 ;115
(1959).
-------
58
Hitch, J. M., Acneform Eruptions Induced by Drugs and Chemicals,
Am. Med. Assoc. J. 200;879 (1967)
Jones, A. T., The Treatment of Casualties from Lung Irritant
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Knott, K. H., and S. Turkolmez, Krupp Rotary Brush Scrubber
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Konig, W., Chemical Warfare Agents (Berlin: German Military
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Koski, T. A., L. S. Stuart, and L. F. Ortenzio, Comparison of
Chlorine, Bromine, and Iodine as Disinfectants for Swimming
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-------
59
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Viola, P. L., Influence of Chlorine on the Poisoning by Mercury
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Occupational Diseases JL:98 (1960).
-------
APPENDIX
-------
61
APPENDIX
TABLE 1
REACTIVITY OF CHLORINE18'24
Flainmability:
Reaction with water:
Reaction with metals:
Reaction with non-
metallic elements:
Reaction with
compounds :
Chlorine is nonflammable; however,
like oxygen gas, it is capable of
supporting combustion of many materials
including hydrogen, reactive metals,
and many organic compounds.
Chlorine reacts with water to produce
hydrochloric acid and hypochlorous
acid (see Equation 1); the latter will
decompose (slowly at normal tempera-
tures) to form hydrochloric acid and
oxygen (see Equation 2). A basic
solution will tend to drive the first
reaction to the right (Equation 1),
whereas acid tends to drive the reac-
tion to the left or produce free
chlorine gas. The second reaction is
irreversible. Chlorine may also form
a hydrate (C12-8HSO) below 49.3°F.
(Equation 1) C12 + HSO £ HC1 + HC10
(Equation 2) 2HC10 -» 2HC1 + O2
Dry chlorine reacts with many metals—
including aluminum, gold, mercury,
selenium, and tin—but is unreactive
to copper, iron, lead, nickel, and
steel at normal temperatures.
Moist chlorine reacts with almost
all metals except gold, platinum,
and titanium.
Chlorine reacts with most other
elements, sometimes very rapidly. It
is unreactive to oxygen and nitrogen
at normal temperatures.
Chlorine reacts with basic materials
to form chlorides and hypochlorites
(e.g., see Equation 3 for reaction
with sodium hydroxide). Chlorine has
a great affinity for a compound con-
taining hydrogen to yield hydrogen
chloride. Many organic compounds are
extremely reactive, yielding organic
chlorinated derivatives and hydro-
chloric acid.
(Equation 3) Cls + 2NaOH TNaCl + NaOCl + H3O
-------
62
APPENDIX
TABLE 2
PHYSICAL PROPERTIES OF CHLORINE18'83
Molecular formula:
Atomic number:
Molecular weight:
Atomic weight:
Isotopes (abundance):
Boiling point:
Melting point:
Color, gas:
Color, liquid:
Odor:
Density, gas, dry, O°C:
Density, gas, saturated, O°C:
Density, liquid (-33.6°C):
Density, liquid (0°C):
Solubility, 10°C:
Solubility, 20°C:
Solubility, 30°C:
Vapor pressure, -10 F:
Vapor pressure, 0 F
Vapor pressure, 20 F:
Vapor pressure, 60 F:
Vapor pressure, 80 F:
C13 (diatomic molecule)
17
70.914
35.457
35 (75.53%)
37 (24.47%)
-34.05°C (-29.29°F)
-100.98°C (-149.76°P)
Greenish yellow
Clear amber
Characteristic: penetrating
and irritating
3.209 g/liter (0.2003 Ib/ft3)
12.07 g/liter (0.7537 Ib/ft3)
1.557 g/liter
1,468 g/liter (91.67 Ib/ft3)
1 vol H2O dissolves
2.7 vol C12 (0.8% by wt)
1 vol H2O dissolves
2.3 vol C18 (0.7% by wt)
1 vol H20 dissolves
1.8 vol C12 (0.5% by wt)
8.29 psig*
13.81 psig*
27.84 psig*
70.91 psig*
101.76 psig*
*psig: pounds per square inch gauge.
-------
APPENDIX
TABLE 3
SUMMARY OF REPORTED HUMAN HEALTH EFFECTS OF INHALATION OF CHLORINE
Concentra-
tion (ppm)
<1.0
1
1-2
1
3.3
3-5
3-6
4
4
Exposure
Time
Several
hours
Effects or Comments
Disturbances and objective symptoms of irritation
created at this concentration
None
Work without interruption possible
Least amount required to produce slight symptoms
after several hours' exposure
Risk to health or life; impossible working
conditions
Tolerable for short periods of time without
objective evidence of injury
Stinging or burning sensation present in the
eyes, nose, and throat; sometimes headache due
to irritation of the accessory nasal sinuses
Maximum amount that can be inhaled for 1 hour
without serious disturbances
Slight smarting of the eyes and irritation of
the nose and throat
Reference
94
85
52, 77
39
94
64
41, 52
39
85
(continued
-------
APPENDIX
TABLE 3 (Continued)
SUMMARY OF REPORTED HUMAN HEALTH EFFECTS OF INHALATION OF CHLORINE
Concentra-
tion (ppm)
~5
5
5
10
>10
14-21
15.1
20
30.2
40-60
50
100
Exposure
Time
Working
condi-
tions
30-60
min
<1 min
0.5-1.0
hr
<30 min
30-60
min
<1 min
Effects or Comments
Premature aging; those exposed suffer from di-
sease of bronchi and become predisposed to
tuberculosis; teeth corrode from hydrochloric
acid produced in mouth; inflammation or ulcera-
tion of the mucous membrane of nose.
Does not endanger life
Noxious effect; impossible to breathe several
minutes
Severe coughing and eye irritation
Immediate and delayed effects; may be serious
Dangerous
Least amount required to cause irritation of
throat
Endangers life
Least amount required to cause coughing
Amount dangerous in 30 minutes to 1 hour
Fatal immediately or eventually
Cannot be tolerated for longer than 1 minute
i
Reference
52, 100
94
39
85
85
52, 126
39
94
39
18
94
52
-------
APPENDIX
TABLE 4
SUMMARY OF REPORTED TOXIC EFFECTS OF INHALATION OF CHLORINE ON ANIMALS
Species
Animals
Animals
Animals
Animals
Animals
Animals
Cat
Cat
Cat
Concentra-
tion (ppm)
-1.5
20.7
-60
200-1,000
-600
1,000
10-100
280-630
300
Exposure
Time
Contin-
uous
60 min
Effects or Comments
Generally still tolerable for animals
No damage when repeatedly exposed
Exposure causes sickness
Respiratory rate increases during
exposure
Death occurs
Brief exposure kills even large animals
Threshold values injurious to health
depending on duration of exposure
Death after 60 minutes of exposure
May cause death after a period during
which conjunctiva is inflamed and there
is coughing and dyspnea
Reference
40, 94
52, 94
43, 94
47, 52
43, 94
41, 52
68, 94
68, 111
52
( continued)
-------
APPENDIX
TABLE 4 (Continued)
SUMMARY OF REPORTED TOXIC EFFECTS OF INHALATION OF CHLORINE ON ANIMALS
Species
Dog
Dog
Dog
Dog
Dog
Dog
Guinea
pigs
Guinea
pigs
Concentra-
tion (ppm)
50-2,000
180-200
(or more)
<280
<650
800
800-900
280-630
Exposure
Time
30 min
30 min
30 min
2.7 hr
30 min
Contin-
uous
Effects or Comments
Decrease, followed by increase, of pulse
rate; increase in respiratory frequency;
initial decrease in temperature;
respiratory acidosis
Pulse rate is retarded during exposure
Death never occurs
Death rarely occurs
Rapidly increasing acidosis
Death occurred sometime after exposure.
Rapid and acute death of 50% of dogs.
Autopsy indicated edema in the lungs
and necrosis of the bronchial epithe-
lium
Small quantities accelerate the course
of experimental tuberculosis
Death after 64 minutes of exposure
Reference
3, 125
6, 52
52
52
52, 54
6, 82
111, 130
4, 52
68, 111
(continued)
-------
APPENDIX
TABLE 4 (Continued)
SUMMARY OF REPORTED TOXIC EFFECTS OF INHALATION OF CHLORINE ON ANIMALS
Species
House
flies
louse
flies
House
flies
House
flies
Souse
flies
House
flies
^ice
Vlice
Concentra-
tion (ppm)
16
63
250
1,000
1,000
1,000
63
250
Exposure
Time
>960 min
840 min
240 min
45 min
10 min
1 hr
>960 min
440 min
Effects or Comments
Approximately 50% died
Approximately 50% died
Approximately 50% died
Approximately 50% died
Approximately 35% died
I
Approximately 76% to 91% died
Approximately 50% died
Approximately 50% died
Reference
130
130
130
130
130
130
130
130
(continued)
-------
APPENDIX
TABLE 4 (Continued)
SUMMARY OF REPORTED TOXIC EFFECTS OF INHALATION OF CHLORINE ON ANIMALS
Species
tfice*
Rabbit
! Excised
trachea)
Rabbits
Rats*
Rats*
Rats*
Concentra-
tion (ppm)
1,000
20-200
-0.7 -
1.7
63
250
1,000
Exposure
Time
28 min
0.5 to
2 min
Up to
9 mos
>960
min
440 min.
53 min
Effects or Comments
Approximately 50% died
Arrest of ciliary activity
Caused loss of weight and an increased
incidence of respiratory disease.
Catarrh-like changes observed in upper
respiratory tract, as well as lung
hemorrhages and emphysema.
Approximately 50% died
Approximately 50% died
Approximately 50% died
Reference
130
130
3, 28
130
130
130
*Autopsy data on exposed rats and mice are given in Table 5.
CD
-------
APPENDIX
Table 5
TYPICAL GROSS FINDINGS AT AUTOPSY OF RATS AND MICE WHICH DIED DURING EXPOSURE
TO CHLORINE (C1P) OR WERE SACRIFICED IMMEDIATELY AFTER GAS TREATMENT130
Organs
Brain
Trachea
Lungs
Heart
Liver
Gall
bladder
Stomach
Intes-
tines
Adrenals
Kidneys
Concentration of Chlorine Gas
3,000,000 uq/m3 (1,000 ppm)
Rats
Slightly congested
Not reddened
Distended, filling
cavity; pale,
waxy cut sur-
faces; foamy
Greatly distended
on right side,
atria distended
Congested
Not distended
Moderately to
greatly distend-
ed, few small
hemorrhages
Large and small,
partly distended
Pink
Congested
Mice
Not congested
Not reddened
Partly col-
lapsed and
hemorrhagic
In systole or
moderately
distended
Congested
Not distended
Same as rats
Natural
Pink
Congested
750,000 uq/m3 (250 ppm)
Rats
Slightly congested
Not reddened
Distended; pale
and waxy, with
scattered hemor-
rhages; wet
Right side slight-
ly dilated
Moderately con-
gested
Not distended
Greatly distended,
very rare small
hemorrhages
Large and small,
moderately
distended
Pale
Congested
Mice
Slightly congested
Not reddened
Deep black-red,
cut surfaces
dripping blood
In systole
Twice natural
size; waxy pale,
nutmeg color
Not distended
Moderately
distended
Slightly
distended
Pale
Pale
189,000 ng/m3
(63 ppm)
Rats*
Slightly congested
Not reddened
Distended; pink,
very rare punc-
tate hemmor
rhages; cut
surfaces wet
and foamy
Right side
distended
Pale to dark red
in color
Not distended
Distended, very
rare punctate
hemorrhages
Small intestine,
moderately dis-
tended; colon
moderately dis-
tended .
Pale to natural
pink in color
Pale to dark red
in color
*Autopsied immediately after exposure.
-------
APPENDIX
TABLE 6
SUMMARY OF REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Alfalfa
Beans
Buckwheat
Buckwheat
leaves
Buckwheat
steins
Azalea
Begonia
Chenopodium
Chinese holly
(Ilex cor-
nuta Lindl)
Concentra-
tion (ppm)
0.1
1.3
0.46
1,000
1,000
0.8
1.0
1.0
0.46 -
4.67
Exposure
Time
2 hr
30 min
60 min
<4 min
120 min
4 hr
4 hr
4 hr
3 hr
Effects or Comments
Incipient injury
Incipient injury
Incipient injury
50% injury to exposed area
50% injury to exposed area
Incipient injury
No visible injury
No visible injury
No visible damage
Reference
13
121, 138
121, 138
123
123
13
13
13
138
(continued)
-------
APPENDIX
TABLE 6 (Continued)
SUMMARY OF REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Coleus (Coleus
blumei Benth)
Corn
Corn
Corn
Cucumber
Corn
Cowpea
Cowpea
Concentra-
tion (ppm)
0.56
0.10 -
0.25
62
62
0.50
62
0.80
62
Exposure
Time
120 min
4 hr
25 min
60 min
4 hr
180 min
4 hr
13 min
Effects or Comments
Incipient injury
Incipient injury
Incipient injury: interveinal
browning of older leaves
Severe damage: all plants
(two) died
Incipient injury
Severe damage: all plants (six)
died
Incipient injury
Incipient injury: loss of
turgor and interveinal necrosis
Reference
138
13
50
50
13
50
13
50
(continued)
-------
APPEJXTDIX
TABLE 6 (Continued)
SUMMARY OF REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Cowpea
Cowpea
Cotton
Cotton
Cotton
Dahlia
Dandelion
Eggplant
Concentra-
tion (ppm)
62
62
62
62
62
0.50
0.50
0.46 -
4.67
Exposure
Time
60 min
180 min
13 min
60 min
180 min
4 hr
4 hr
180 min
Effects or Comments
Moderate damage but plants sur-
vived
Severe damage but plants sur-
vived
Incipient injury: brown ne-
crosis of cotyledons and
leaves along margins
Moderate damage but plants
survived
Severe damage but plants
survived
Incipient injury
Incipient injury
No visible damage
Reference
50
50
50
50
50
13
13
138
(continued)
-------
APPENDIX
TABLE 6 (Continued)
SUMMARY OF REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Geranium
Gomphrena
Halsea sp.
Mustard
Nasturtium
Oxalis
Onion
Peach
Pepper
Petunia
Concentra-
tion (ppm)
0.80
0.10-
0.25
0.56
0.10 -
0.25
0.50
1.0
0.10 -
0.25
0.56
1.0
0.80
Exposure
Time
4 hr
4 hr
120 min
4 hr
4 hr
4 hr
4 hr
180 min
4 hr
4 hr
Effects or Comments
Incipient injury
Incipient injury
Incipient injury
Incipient injury
Incipient injury
No visible damage
Incipient injury
Incipient injury
No visible injury
Incipient injury
Reference
13
13
138
13
13
13
13
121, 138
13
13
(continued)
co
-------
APPENDIX
TABLE 6 (Continued)
SUMMARY OP REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Polygonum
Pinto bean
Radish (Rapha-
nus sativus
L.)
Radish
Radish seeds,
dry
Radish seeds,
soaked
Rhodo typos
sp.
Concentra-
tion (ppnO
1.0
0.80
1.3
0.1
250 and
1,000
250 -
1,000
250
L,000
1.3
Exposure
Time
4 hr
4 hr
30 min
2 hr
1 -
960 min
1 -
240 min
960 min
960 min
30 min
Effects or Comments
No visible injury
Incipient injury
Incipient injury
Incipient injury
Germination not affected
Germination not affected
Germination reduced by about
15-20%
Germination reduced by about
90-95%
Incipient injury
Reference
13
13
121, 138
13
7
7
138
(continued)
-------
APPENDIX
TABLE 6 (Continued)
SUMMARY OF REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Roses ( Rosa)
Rye seeds, dry
Rye seeds,
soaked
Concentra-
tion (ppm)
1.5
250-
1,000
250
1,000
250
1,000
250
250
1,000
1,000
1,000
Exposure
Time
30 min
1-240
min
960 min
960 min
1-60 min
1 min
240 min
960 min
60 min
240 min
960 min
Effects or Comments
Incipient injury
Little effect on germination
Germination reduced by approxi-
mately 10%
Germination reduced by approxi-
mately 50%
Little effect on germination
ii n n
Germination reduced by approxi-
mately 26%
Germination reduced by approxi-
mately 68% and bleaching of seeds
Germination reduced by approxi-
mately 20%
70%
No germination and bleaching of
seeds
Reference
121, 138
7
7
(continued)
-------
APPENDIX
TABLE 6 (Continued)
SUMMARY OF REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Scotia bean
Squash
Squash
Soybean
Sunflower
Concentra-
tion ( ppm )
0.80
0.80
62
62
62
62
62
62
0.10-
0.25
Exposure
Time
4 hr
4 hr
13 min
60 min
180 min
13 min
60 min
180 min
4 hr
Effects or Comments
Incipient injury
Incipient injury
Incipient injury: loss of tur-
gor, interveinal necrosis of
young mature leaves
Severe damage but plants sur-
vived
All plants died (total of six)
Incipient injury: loss of
turgor
Moderate injury but plants
survived
Severe injury but plants
survived
Incipient injury
Reference
13
13
50
50
13
(continued)
-------
APPENDIX
TABLE 6 (Continued)
SUMMARY OF REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Tobacco
Tobacco leaves
Tobacco stems
Tomato
Tomato leaves
Tomato leaves
Concentra-
tion (ppm)
0.10-
0.25
1,000
1,000
0.5
0.40
0.60
0.6
1.4
1.4
L,000
1,000
250
Exposure
Time
4 hr
0 . 5 min
60 min
4 hr
6 hr
2 hr
3 hr
2 hr
1 hr
0 . 8 min
~0 . 6 min*
-0.6 min*
Effects or Comments
Incipient injury
50% injury to exposed areas
50% injury to exposed areas
Incipient injury
No visible injury to leaves
No visible injury to leaves
Moderate injury to leaves
Severe injury to leaves
Moderate injury to leaves
50% injury to exposed area
Clear weather: 50% injury to
exposed area
ii M ii
Reference
13
123
123
13
13
13, 123
(continued)
-------
APPENDIX
TABLE 6 (Continued)
SUMMARY OF REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Tomato leaves
Tomato stems
Concentra-
tion (ppm)
63
4
1,000
250
16
1,000
1,000
250
63
4
1,000
250
16
Exposure
Time
-0.8 min*
—9 . 5 min*
— 1 min*
—4 min*
-120 min*
22 min
~150 min*
-35 min*
-520 min*
-240-
600 min*
-9.5 min*
>960 min*
-520 min*
Effects or Comments
Clear weather: 50% injury to
exposed area
ii n ii
Cloudy weather: 50% injury to
exposed area
n n n
n n n
50% injury to exposed area
Clear weather: 50% injury to
exposed area
n i n
n n n
n n M
Cloudy weather: 50% injury to
exposed area
n n ii
„
Reference
13, 123
123
CO
(continued)
-------
APPENDIX
TABLE 6 (Continued)
SUMMARY OP REPORTED EFFECTS OF CHLORINE GAS EXPOSURE ON PLANT LIFE
Plant
Wheat, oat,
and barley
seeds
Zinnia
Concentra-
tion (ppm)
3,000-
9,000
0.10-
0.25
Exposure
Time
1-2 hr
4 hr
Effects or Comments
No visible injury
Incipient injury
Reference
70
13
*Data compiled from a graph.
-------
80
APPENDIX
TABLE 7
CHLORINE PRODUCTION IN THE UNITED STATES
(Short Tons per Year)
29
Year
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
Liquid
2-, 000, 318
2,233,329
2,398,031
2,478,007
2,755,162
2,920,127
3,120,201
3,484,312
3,853,628
3,950,540
Gas*
3,604,538
4,347,118
4,636,939
4,600,791
5,142,876
5,464,080
5,945,215
6,517,079
7,205,165
7.653,881
*The figure given for gas includes
the figure given for liquid.
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81
APPENDIX
TABLE 8
MAJOR PRODUCERS OF CHLORINE GAS AND LIQUID IN THE U.S.122
Company
Location
Adirondack Chemical Co.
Allied Chemical Corp.,
Industrial Chemicals Div.
American Oil & Supply Co.
Brown Co.
Calvert Chemical Co.
Diamond Alkali Co.
Dow Chemical Co.
Field Point Mfg. Corp.
FMC Corp.,
Inorganic Chemicals Div.
General Aniline & Film Corp.
General Biochemicals, Inc.
Georgia-Pacific Corp.
Globe Chemical Co., Inc.
Haviland Products Co.
Hooker Chemical Corp.,
Industrial Chemicals Div.
Hubbard-Hall Chemical Co.
Jones Chemicals Inc.
Joseph, E. R., Co., Inc.
Kingston Chemical Co., Inc.
Modern Pool Products, Inc.
Ocean Pool Supply Co^
Olin Mathieson Chemical Corp.,
Chemicals Div.
Peebles Chemical Co.
Pennsalt Chemical Corp.
Phillip Brothers Chemicals, Inc.
PPG Industries,
Chemical Div.
Precision Gas Products, Inc.
Robinson Bros. Chemicals, Inc.
Seaway Chemical Corp.
Sergeant, E. M., Pulp &
Chemical Co., Inc.
Sherwood Overseas Corp.
Stauffer Chemical Co.,
Industrial Chemical Div-
Tesco Chemicals, Inc.
Vulcan Materials Co.
Wittichen Chemical Co.
Wyandotte Chemicals Corp.,
Industrial Chemicals Group
Plattsburgh, N.Y.
Morristown, N.J.
Newark, N.J.
New York, N.Y.
Cincinnati, Ohio
Cleveland, Ohio
Midland, Mich.
Providence, R.I.
New York, N.Y.
New York, N.Y.
Chagrin Falls, Ohio
Portland, Oreg.
Cincinnati, Ohio
Grand Rapids, Mich.
Niagara Falls, N.Y.
Waterbury, Conn.
Caledonia, N.Y.
Norristown, Pa.
New York, N.Y.
Stamford, Conn.
Huntington Station,
Long Island, N.Y.
New York, N.Y.
Kenilworth, Md.
Philadelphia, Pa.
New York, N.Y.
Pittsburgh, Pa.
Linden, N.J.
Brooklyn, N.Y.
Buffalo, N.Y.
New York, N.Y.
New York, N.Y.
New York, N.Y.
Atlanta, Ga.
Birmingham, Ala.
Birmingham, Ala.
Wyandotte, Mich.
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APPENDIX
82
TABLE 9
CONSUMPTION OF CHLORINE BY USES, 1963-64
19
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.
25.
Use
Vinyl and vinylidine chloride
monomers
Other chlorinated hydrocarbons
Glycerine and glycols
Metal alkyds, including tetra-
ethyl lead or tetramethyl lead
Bleaching compounds (excludes
quantities used for pulp and
paper and textile bleaching
and finishing)
Phosphates
Silicates
Soap and synthetic detergents.
other than above
Pesticides
Other chemicals
Rubber reclaiming processes
Water and sewage treatment
Pulp and paper manufacture
Textile bleaching and
finishing
Glass
Cellophane
Rayon
Aluminum and other production
and ore-treating
Food
Pharmaceutical s
Petroleum production and
refining
Other uses
Sales to dealers
Sales to government
Exports
Total consumption (in
thousands of short tons)
Percent of
1963
-7 Ca
7 . 6
31.8
14.0
b
2.0
2.0
1.0
0
0.2
4.2
10.9<3
0.1
1.2e
15.4
0.1
0
c
c
0.3
0.4
0.1
0.2
r) -F
6.1a'£
3.6
0.3
0.5
5,576
Total
1964
8.8a
31.4
14.6
b
2.1
0.5
0
c
4.0
10. 8d
0.2
1 9e
X • Z
14.9
0.1
0
c
c
0.3
0.4
0.1
0.2
rt f
6.la/:C
3.4
0.3
0.6
6,096
aProbably greater; some chlorine intended for plastics and
chlorinated organics was reported under Item 10.
^Withheld to avoid disclosure of figures for individual companies,
GLess than 0.05 percent
^Items 10 and 22 also include such uses as for aluminum, ammonium
and calcium chlorides, boric acid, bromine, rubber chemicals, paint
coatings, ferric chloride, etc.
^Probably greater, approximately 3.5 percent; some chlorine for
water and waste treatment was included in Items 10, 22, 23.
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