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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

-------
                                                         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

-------
                                                         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

-------
                                                         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

-------
                                                        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.

-------
                                                        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).

-------
                                                        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.

-------
                                                            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.

-------
                                                             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.

-------
                                                            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.

-------
                                                             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.

-------
                                                        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

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                                                         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

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                                                        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.

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                                                        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

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                                                          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.

-------
                                                            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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-------
                                                        54
120.  Takhirov, M. T., Determination of Limits of Allowable
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-------
                                                        55
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-------
                                                        56
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                                                        57
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-------
                                                         58
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                                                        59
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-------
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

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                                                       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)

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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)

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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

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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)

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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)

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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)

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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)

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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)

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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.

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                                                        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.

-------