Acute Exposure Guideline Levels (AEGLS) for Tear Gas (cs) (CAS Reg. No. 2698-41-1) C10h5cln2 Interim


Interim: September 2009

ACUTE EXPOSURE GUIDELINE LEVELS (AEGLs)

FOR
TEAR GAS (CS)

(CAS Reg. No. 2698-41-1)

C10H5C1N2

INTERIM

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Interim: September 2009

ACUTE EXPOSURE GUIDELINE LEVELS (AEGLs)

FOR
TEAR GAS
(CAS Reg. No. 2698-41-1)

INTERIM

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PREFACE

Under the authority of the Federal Advisory Committee Act (FACA) P. L. 92-463 of
1972, the National Advisory Committee for Acute Exposure Guideline Levels for Hazardous
Substances (NAC/AEGL Committee) has been established to identify, review and interpret
relevant toxicologic and other scientific data and develop AEGLs for high priority, acutely toxic
chemicals.

AEGLs represent threshold exposure limits for the general public and are applicable to
emergency exposure periods ranging from 10 minutes to 8 hours. Three levels - AEGL-1,
AEGL-2 and AEGL-3 — are developed for each of five exposure periods (10 and 30 minutes, 1
hour, 4 hours, and 8 hours) and are distinguished by varying degrees of severity of toxic effects.
The three AEGLs are defined as follows:

AEGL-1 is the airborne concentration (expressed as parts per million or milligrams per
cubic meter [ppm or mg/m3]) of a substance above which it is predicted that the general
population, including susceptible individuals, could experience notable discomfort, irritation, or
certain asymptomatic, non-sensory effects. However, the effects are not disabling and are
transient and reversible upon cessation of exposure.

AEGL-2 is the airborne concentration (expressed as ppm or mg/m3) of a substance above
which it is predicted that the general population, including susceptible individuals, could
experience irreversible or other serious, long-lasting adverse health effects or an impaired ability
to escape.

AEGL-3 is the airborne concentration (expressed as ppm or mg/m3) of a substance above
which it is predicted that the general population, including susceptible individuals, could
experience life-threatening health effects or death.

Airborne concentrations below the AEGL-1 represent exposure levels that could produce
mild and progressively increasing but transient and nondisabling odor, taste, and sensory
irritation or certain asymptomatic, non-sensory effects. With increasing airborne concentrations
above each AEGL, there is a progressive increase in the likelihood of occurrence and the
severity of effects described for each corresponding AEGL. Although the AEGL values
represent threshold levels for the general public, including susceptible subpopulations, such as
infants, children, the elderly, persons with asthma, and those with other illnesses, it is recognized
that individuals, subject to unique or idiosyncratic responses, could experience the effects
described at concentrations below the corresponding AEGL.

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1	TABLE OF CONTENTS

2	PREFACE	3

3	TABLE OF CONTENTS	4

4	LIST OF TABLES	6

5	SUMMARY	7

6	1. INTRODUCTION	9

7	2. HUMAN TOXICITY DATA	10

8	2.1. Acute lethality	10

9	2.2 Nonlethal acute toxicity	10

10	2.2.1. Experimental studies	10

11	2.2.2. Case reports	17

12	2.3. Developmental/Reproductive Toxicity	18

13	2.4. Genotoxicity	19

14	2.5. Summary	19

15	3. ANIMAL TOXICITY DATA	20

16	3.1. Acute Lethality	20

17	3.1.1. Monkeys	20

18	3.1.2. Rats	22

19	3.1.3. Mice	25

20	3.1.4. Guinea Pigs	25

21	3.1.5. Rabbits	26

22	3.1.6. Hamsters	27

23	3.1.7. Dogs	27

24	3.2. Nonlethal Acute Toxicity	31

25	3.2.1. Mice	31

26	3.2.2. Rabbits	31

27	3.3. Repeat Dose Studies	32

28	3.3.1. Rats	32

29	3.3.2. Mice	33

30	3.3.3 Rats, Mice, Guinea Pigs, Rabbits	33

31	3.4. Developmental/Reproductive Toxicity	34

32	3.5. Genotoxicity	35

33	3.6. Chronic Toxicity/Carcinogenicity	36

34	3.7. Summary	37

35	4. SPECIAL CONSIDERATIONS	38

36	4.1. Metabolism and Disposition	38

37	Absorption	38

38	T oxico kinetics	38

39	Metabolism	38

40	Distribution and Elimination	40

41	4.2. Mechanism of Toxicity	41

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1	4.3. Other Relevant Information	41

2	4.3.1. Species Variability	41

3	4.3.2. Susceptible Populations	42

4	4.3.3. Concentration-Exposure Duration Relationship	42

5	5. DATA ANALYSIS FOR AEGL-1	42

6	5.1. Summary of Human Data Relevant to AEGL-1	42

7	5.2. Summary of Animal Data Relevant to AEGL-1	42

8	5.3. Derivation of AEGL-1	43

9	6. DATA ANALYSIS FOR AEGL-2	43

10	6.1. Summary of Human Data Relevant to AEGL-2	43

11	6.2. Summary of Animal Data Relevant to AEGL-2	43

12	6.3. Derivation of AEGL-2	44

13	7. DATA ANALYSIS FOR AEGL-3	44

14	7.1. Summary of Human Data Relevant to AEGL-3	44

15	7.2. Summary of Animal Data Relevant to AEGL-3	44

16	7.3. Derivation of AEGL-3	45

17	8. SUMMARY OF AEGLs	46

18	8.1. AEGL Values and Toxicity Endpoints	46

19	8.2. Comparison with Other Standards and Guidelines	46

20	9. REFERENCES	47

21	APPENDIX A: DERIVATION OF TEAR GAS AEGLS	53

22	APPENDIX B: TIME SCALING CALCULATIONS	57

23	APPENDIX C: DERIVATION SUMMARY FOR TEAR GAS	61

24	APPENDIX D: CATEGORY PLOT FOR TEAR GAS	64

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LIST OF TABLES

S 1. SUMMARY OF AEGL VALUES FOR TEAR GAS	8

TABLE 1. CHEMICAL AND PHYSICAL PROPERTIES	10

TABLE 2. RESULTS OF HUMAN EXPOSURE TO ONE OR SIXTY MICRON CS AEROSOLS: TOLERANCE

AND RECOVERY TIME	11

TABLE 3. SYMPTOMS OF 34 VOLUNTEERS EXPOSED TO CS AEROSOL FOR 60 MINUTES	15

TABLE 4. SUMMARY OF EXPOSURE TIME OF VOLUNTEERS: SUBJECTS EXPOSED TO CS UNTIL

THEY COULD NO LONGER TOLERATE THE EXPOSURE OR FOR A MAXIMUM OF 10 MINUTES. 16
TABLE 5. SUMMARY OF EXPOSURE TIME OF VOLUNTEERS: SUBJECTS EXPOSED TO CS UNTIL

THEY COULD NO LONGER TOLERATE THE EXPOSURE	16

TABLE 6. SUMMARY OF SELECTED HUMAN ACUTE INHALATION TOXICITY/INTOLERANCE DATA20
TABLE 7. MORTALITY DATA IN RATS, MICE, GUINEA PIGS, RABBITS, DOGS, AND MONKEYS

FOLLOWING INHALATION EXPOSURE TO CS AEROSOL	29

TABLE 8. SUMMARY OF ACUTE TOXICITY DATA IN RATS AND HAMSTERS	30

TABLE 9. SUMMARY OF MORTALITY OF GUINEA PIGS, RABBITS, RATS, AND MICE EXPOSED TO CS

	30

TABLE 10. SUMMARY OF MORTALITY DATA IN RATS, RABBITS, AND GUINEA PIGS FOLLOWING

INHALATION EXPOSURE TO CS	31

TABLE 11. SUMMARY OF MORTALITY OF GUINEA PIGS, RABBITS, RATS, AND MICE EXPOSED TO CS

FOR 5 I I/DAY FOR UP TO 7 DAYS	34

TABLE 12. AEGL-1 VALUES FOR TEAR GAS	43

TABLE 13. AEGL-2 VALUES FOR TEAR GAS	44

TABLE 14. AEGL-3 VALUES FOR TEAR GAS	45

TABLE 15. SUMMARY OF AEGL VALUES	46

TABLE 16. STANDARDS AND GUIDELINES FOR TEAR GAS	46

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SUMMARY

Tear Gas (o-Chlorobenzylidenemalonitrile; CAS No. 2698-41-1) is a white crystalline
powder with a pepper-like odor. It was first synthesized by Corson and Stoughton in 1928 (thus
the abbreviation "CS") (Corson and Stoughton, 1928; U.S. Army et al., 2005). It was developed
in the 1950s as a replacement for the chemical incapacitant CN (1-chloroacetophenone) used by
police because CS was a much more potent irritant than CN, but was significantly less toxic
(WHO, 1970; Hu et al., 1989; Colgrave and Creasey, 1975). It was adopted for use by the
military shortly after, and was widely used in Vietnam (Hu et al., 1989; WHO, 1970). It is
currently used as an incapacitating agent both by military and law enforcement personnel
(HSDB, 2008). It is reported that an aerosol concentration of 4 mg/m3 will disperse the majority
of rioters within 1 minute, and 10 mg/m3 will deter trained troops (Upshall, 1973). With the
exception of more severe cutaneous reactions, recovery from exposure is generally rapid upon
exposure to fresh air, generally within 30 minutes after exposure (Ballantyne, 1977). CS may be
manufactured through carbonyl condensation by combining o-chlorobenzaldehyde and
malononitrile (HSDB, 2008). Recent production data were not located.

The AEGL-1 values were based on human exposure to 1.5 mg/m3 for 90 minutes (Punte et
al., 1963). All four subjects could tolerate the exposure, but experienced eye and nose irritation
and headache. One subject developed nasal irritation within 2 minutes, three subjects developed
headache (at 45, 50, and 83 minutes), and all four experienced ocular irritation (at 20, 24, 70, and
75 minutes). A modifying factor of 10 was applied to reduce the point-of-departure from a
LOAEL to a NOAEL for AEGL-1 effects. An intraspecies uncertainty factor of 3 was applied
because contact irritation is a portal-of-entry effect and is not expected to vary widely among
individuals. The intraspecies UF of 3 is also supported by the fact that responses of volunteers
with jaundice, hepatitis, or peptic ulcer or those that were 50-60 years old were similar to those
of "normal" volunteers when exposed to a highly irritating concentration of CS for short
durations (Punte et al., 1963; Gutentag et al., 1960). An interspecies uncertainty factor of 1 was
applied because the study was conducted in humans. Time scaling was not applied in the
development of the AEGL-1 values, because the critical effect (irritation) is a function of direct
contact with the tear gas and is not likely to increase with duration of exposure at this level of
severity (NRC, 2001).

The AEGL-2 values were based on human exposure to 1.5 mg/m3 for 90 minutes (Punte et
al., 1963). All four subjects could tolerate the exposure, but experienced eye and nose irritation
and headache. One subject developed nasal irritation within 2 minutes, three subjects developed
headache (at 45, 50, and 83 minutes), and all four experienced ocular irritation (at 20, 24, 70, and
75 minutes). An intraspecies uncertainty factor of 3 was applied because contact irritation is a
portal-of-entry effect and is not expected to vary widely among individuals. The intraspecies UF
of 3 is also supported by the fact that responses of volunteers with jaundice, hepatitis, or peptic
ulcer or those that were 50-60 years old were similar to those of "normal" volunteers when
exposed to a highly irritating concentration of CS for short durations (Punte et al., 1963;

Gutentag et al., 1960). An interspecies uncertainty factor of 1 was applied because the study was
conducted in humans. Time scaling was not applied in the development of the AEGL-2 values,
because the critical effect (irritation) is a function of direct contact with the tear gas and is not
likely to increase with duration of exposure at this level of severity (NRC, 2001).

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AEGL-3 values were based on the threshold for lethality at each AEGL-3 exposure
duration calculated using the probit-analysis based dose-response program of ten Berge (2006).
Rat lethality data of McNamara et al.(1969); Ballantyne and Calloway (1972); and Ballantyne
and Swantson (1978) were used in the calculation, and the threshold for lethality was set at the
LCoi. The rat data indicated a time-scaling value of 0.704 (C°'704x t = k). The 4-hour AEGL-3
value was adopted as the 8-hour AEGL-3 value because time scaling yielded an 8-hour value
inconsistent with the AEGL-2 values that were derived from a rather robust human data set.

This is likely a result of the methodology (time-scaling to 8-hrs with an exponent 'n' of 0.704).

Inter- and intraspecies uncertainty factors of 3 each were applied (total 10) and are
considered sufficient because clinical signs are likely caused by a direct chemical effect on the
tissues. This type of portal-of-entry effect is not likely to vary greatly between species or among
individuals. The interspecies UF of 3 is supported by calculated LCt50 values of 88,480 mg
min/m3 for rats; 67,200 mg min/m3 for guinea pigs; 54,090 mg min/m3 for rabbits; and 50,010 mg
min/m3 for mice (Ballantyne and Swantson, 1978), values all well within a factor of two.
The intraspecies UF of 3 is supported by the fact that responses of volunteers with jaundice,
hepatitis, or peptic ulcer or those that were 50-60 years old were similar to those of "normal"
volunteers when exposed to highly irritating concentration of CS for short durations (Punte et al.,
1963; Gutentag et al., 1960).

The calculated values are listed in the table below.

S 1. Summary of AEGL Values for Tear Gas

Classification

10-min

30-min

1-h

4-h

8-h

Endpoint
(Reference)

AEGL-1
(Nondisabling)

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

NOAEL for
Ocular/nasal
irritation and
headache in humans
(Punte et al., 1963)

AEGL-2
(Disabling)

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

Ocular/nasal
irritation and
headache in humans
(Punte et al., 1963)

AEGL-3
(Lethal)

140 mg/m3

29 mg/m3

11 mg/m3

1.5 mg/m3

1.5 mg/m3

Threshold for
lethality (LC0i) in
rats [McNamara et
al.(1969); Ballantyne
and Calloway
(1972); and
Ballantyne and
Swantson (1978)]

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1. INTRODUCTION

Tear Gas (CioH5C1N2; CAS No. 2698-41-1) is a white crystalline powder with a pepper-like
odor. It was first synthesized by Corson and Stoughton in 1928 (thus the abbreviation "CS")
(Corson and Stoughton, 1928; U.S. Army et al., 2005). It was developed in the 1950s as a
replacement for the chemical incapacitant CN (1-chloroacetophenone) used by police because
CS was a much more potent irritant than CN, but was significantly less toxic (WHO, 1970; Hu et
al., 1989; Colgrave and Creasey, 1975). It was adopted for use by the military shortly after, and
was widely used in Vietnam (Hu et al., 1989; WHO, 1970; Smith and Greaves, 2002). It is
currently used as an incapacitating agent both by military and law enforcement personnel
(HSDB, 2008). It is reported that an aerosol concentration of 4 mg/m3 will disperse the majority
of rioters within 1 minute, and 10 mg/m3 will deter trained troops (Upshall, 1973). With the
exception of more severe cutaneous reactions, recovery from exposure is generally rapid upon
exposure to fresh air, usually within 30 minutes after exposure (Ballantyne, 1977).

Because CS is stable when heated and has a low vapor pressure, it requires a means of
dispersement (Blain, 2003). Different forms of dispersement include the combination of CS with
a pyrotechnic compound in a grenade or canister, generating a smoke or fog, and dispersement of
a fine powder as an aerosol (Smith and Greaves, 2002; WHO, 1970). CS1 is a micronized
powder formulation of CS containing 5% silica gel for dissemination by an explosive burst or
dusting apparatus, and CS2 is the same as CS1 except that the CS1 is microencapsulated with
silicone to improve its weather resistance and flow properties (WHO, 1970).

In controlled studies investigating the toxicological properties of CS aerosol, CS was
disseminated from a 2% to 10% solution in methylene chloride or acetone by means of a
pneumatic atomizing nozzle assembly (Owens and Punte, 1963; Punte et al., 1963; Gutentag et
al., 1960) or by thermal dispersion by spraying the molten chemical (Punte et al., 1963; Gutentag
et al., 1960; Punte et al., 1962).

CS may be manufactured through carbonyl condensation by combining o-
chlorobenzaldehyde and malononitrile (HSDB, 2008). Recent production data were not located.

Hydrolysis of CS produces malononitrile and o-chlorobenzaldehyde (NTP, 1990).

Hydrolysis of CS is relatively rapid, with a half-life of about 15 minutes at a pH 7, but CS reacts
faster with an alkaline solution, having a half-life of about 1 minute at a pH of 9 (Blain, 2003).

When released to the air, CS will exist in both vapor and aerosol form (HSDB, 2008). CS in
the vapor phase will be degraded by reaction with photochemically produced hydroxyl radicals,
with an estimated half-life of 110 hours, and CS in the particulate phase will be removed by wet
and dry deposition.

Chemical and physical properties are presented in Table 1.

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TABLE 1. Chemical and Physical Properties

Parameter

Value

Reference

Synonyms

CS; o-Chlorobenzylidenemalonitrile; 2-
Chlorobenzalmalononitrile; 0-
Chlorobenzylidenemalononitrile; ((2-Chloro-
phenyl)methylene)propanenitrile; 2-
Chlorobmn; Alonitrile; beta,beta-Dicyano-o-
chlorostyrene; Propanedinitrile, ((2-
chlorophenyl)methylene)-

O'Neiletal., 2001

Chemical formula

c10h5cin2

O'Neiletal., 2001

Molecular weight

188.6

O'Neiletal., 2001

CAS Reg. No.

2698-41-1

O'Neiletal., 2001

Physical state

White crystalline solid

O'Neiletal., 2001

Solubility in water (g/L)

Sparingly soluble
2.0 x 10"4 M

O'Neiletal., 2001;
ACGIH, 1991

Vapor pressure

3.4 x 10"5 mmHg



Vapor density (air =1)

6.5

U.S. Army et al., 2005

Density (solid)

bulk: 0.24-0.26 g/mL;
crystal: 1.04 g/mL

U.S. Army et al., 2005

Melting point

95°-96°C

ACGIH, 1991

Boiling point

310°C to 315°C

U.S. Army, 2005

Henry's Law Constant

1.0 x 10-8

HSDB, 2008

(atm-m3/mol)





Volatility

0.71 mg/m3 @ 25°C

U.S. Army et al., 2005

Stability /reactivity

Combustible material; may burn but does not
ignite readily

U.S. Army et al., 2005

Conversion factors

1 ppm= 7.71 mg/m3

Calculated:



1 mg/m3 = 0.13 ppm

DD111 x M. W. = me/m3
24.45

2. HUMAN TOXICITY DATA
2.1. Acute lethality

No human acute lethality data were located.

2.2 Nonlethal acute toxicity
2.2.1. Experimental studies

In a review article, Blain (2003) reported a TC50 (defined as the concentration required to
obtain no more than a perceptible effect on 50% of the population exposed to the gas for 1
minute) of 0.004 mg/m3 for ocular irritation and 0.023 mg/m3 for airway irritation. An ICT50
(the concentration intolerable to 50% of the population for 1 minute) was also reported. No
further details were presented.

A group of male volunteers was exposed to CS aerosol with a mass-median diameter of 0.9
microns (94 ±15 mg/m3; 4% larger than 10 micron) or of 60 microns (85 ±16 mg/m3; 4%
smaller than 20 microns) to assess differences in ocular and respiratory responses to different
particulate sizes of CS (Owens and Punte, 1963). Six volunteers were chosen from a group of
approximately fifty based on their ability to best tolerate CS. Subjects wore tightly fitted

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goggles and a nose and mouth respirator designed to protect against particle sizes less than one
micron, and were exposed individually in a wind tunnel with a constant air speed of 5 mph. The
exposure protocol was designed such that either eyes only, the respiratory system only, or eyes
and the respiratory system could be exposed to either the small or large particles. The wind
tunnel was elevated to a height of five feet, and a rubber-lined port was installed in the bottom of
the duct enabling the subject to insert his head into the airstream of the tunnel and remove it
quickly after the exposure. CS was disseminated from a 2% solution in methylene chloride by
means of a pneumatic atomizing nozzle assembly. CS exposure concentrations were determined
by collection of air samples using filter paper placed on air sampling probes located around the
head area (one on top and one on each side near eye level), followed by extraction with ethanol
and measurement with ultraviolet spectrophotometry. A modified cascade impactor was used to
measure the CS aerosol containing the small particles, while the larger particles were sized
microscopically, measuring and counting the various particles in the pre-ground material prior to
dissemination. Tolerance time was defined as the time at which a subject could no longer remain
in the atmosphere containing the compound and left the exposure chamber, and recovery time
was defined as the time after the exposure when the subjects were able to sort and arrange a
series of twenty-four playing cards from which the corner numbers were removed. Control
values were determined before each test. The results indicate that small particles are more
effective in rapidly producing eye irritation (Table 2). It is hypothesized that the onset of ocular
response is faster with small particles because of the ease of solubility of the small particles in
the eye fluid, while the onset of irritation would be delayed for the large particles due to the
slowness of the large particle solubility. Once begun, however, the irritation process would
continue for a longer period with the large particles compared to the small particles. Respiratory
effects were more severe for the small particles (no volunteers could withstand exposure for
more than 30 seconds) and required more time for recovery than the large particles. The
difference in response is due to the fact that the smaller-sized particulates are able to penetrate
more deeply into the respiratory tract. When both the eyes and the respiratory system were
exposed to CS, the respiratory response predominated with exposure to the small particulates,
while the ocular response predominated with exposure to the large.

TABLE 2. Results of human exposure to one or sixty micron CS aerosols: Tolerance and recovery time

Exposure Condition

% Subjects able to tolerate a 60-sec exposure

Recovery Time (sec)

Small particles a

Large particles b

Small particles a

Large particles b

Eyes

40

100

91

280

Respiratory system

0

67

51

9*

Eyes and respiratory system

16

85

52

188

Taken from Owens and Punte, 1963
a Measured concentration of 94 ± 15 mg/m3
b Measured concentration of 85 ± 16 mg/m3

A group of 4-6 volunteers was exposed to CS aerosol in a wind tunnel (8x8x8 ft; fixed wind
speed of 5 mph) (Punte et al., 1963; Gutentag et al., 1960). Volunteers were both military and
civilian. Each volunteer's medical history was recorded, and they were given a pre-exposure and
post exposure physical examination. Volunteers were classified as "normal" or were placed in
one of four special categories: those with hypertension (diastolic of 80-110 mm Hg or normal
blood pressure reading with a history of hypertension; pre-exposure tests included EKG, chest
X-ray, NPN, and urinalysis); those with hay fever, drug sensitivity, or bronchial asthma
(volunteers with asthma had normal chest X-ray before exposure); those with a history of

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jaundice, hepatitis, or a history of peptic ulcers without gastrointestinal bleeding; and those that
were 50-60 years of age. Subjects classified as "normal" were further categorized into untrained
men with or without protective masks or trained men with or without protective masks. The
trained men had previous exposure with CS, while the untrained men did not. The CS was
dispersed either from a 10% solution in acetone or methylene dichloride with a spray nozzle
(mass mean diameter 3.0 or 1.0 micron, respectively) or by thermal dispersion (spraying the
molten chemical; mass mean diameter 0.5 micron). Airborne samples of the aerosol were
collected at various points in the wind tunnel. Particle size was characterized using a 6-stage
modified cascade impactor, and exposure concentrations were measured using u.v.
spectrophotometry. The subjects did not report any noticeable difference in symptoms when
exposed to chemically dispersed CS compared to thermal dispersion. Groups of 3-6 untrained
men without masks were exposed to CS in acetone, and the time to incapacitation was recorded
(time at which the subject could no longer tolerate the exposure). Times ranged from 53 to >120
seconds at exposure to 5 mg/m3; 19-43 seconds at exposure to 12 mg/m3; to 5 seconds at
exposure to 442 mg/m3. When groups of 1-7 trained men were exposed, times ranged from 37 to
>120 seconds at 4 mg/m3; 18-41 seconds at 10 mg/m3; to 12-25 seconds at 141 mg/m3. To
compare the effects of hyperventilation on exposure symptoms, untrained subjects ran for
approximately 100 yards before exposure. Exercising subjects could not tolerate CS as well as
normally breathing subjects: groups of three subjects exposed to 10, 13, or 39 mg/m3 could
tolerate CS up to 13, 13, and 9 seconds, respectively. While eye irritation was minimal, chest
symptoms were more pronounced and recovery time was slightly prolonged (by 1-2 minutes).
The reactions of subjects with jaundice, hepatitis, or peptic ulcer or those that were 50-60 years
old were similar to those of "normal" subjects. Subjects with a history of drug allergies or
sensitivities, hay fever, or asthma also tolerated exposure to CS at a level comparable to the
"normal" subjects, but this group had a higher percentage of individuals with more severe chest
symptoms, with many of them laying prostrate on the ground for several minutes. However, no
wheezing or rhonchi were heard, and recovery was as rapid as that seen in other exposure
groups. When subjects were exposed to CS at temperatures ranging from 0° up to 95°F,
tolerance to the chemical was slightly reduced at the high temperature of 95°F. It was unclear if
the decrease in tolerance was an actual effect of the exposure, the uncomfortable climate, or a
combination of both. The increase in skin burning symptoms with the increased temperature was
ascribed to an increase in perspiration.

As part of the study described above, the potential for development of tolerance to CS was
investigated by exposing a group of 4 subjects to 1.5 mg/m3 of CS for 90 minutes in a 20,000 L
chamber (Punte et al., 1963). No data were provided regarding the monitoring of the CS aerosol.

During the exposure, subjects were allowed to smoke, read, play cards, etc. During the
exposure, only one subject noted nose irritation (noted 2 minutes into exposure), while three
subjects reported headaches (starting at 45, 50, and 83 minutes) and all four subjects reported
eye irritation (starting at 20, 24, 70, and 75 minutes). In the second part of the experiment, the
four subjects were exposed to 1.5 mg/m3 of CS for 40 minutes, after which enough additional CS
aerosol was added to attain an airborne concentration of 11 mg/m3 in about 10 minutes.

Although the subjects had not been told of the increase in concentration, they all left within 2
minutes due to respiratory irritation. It was estimated that the exposure concentration ranged
from 4.3 to 6.7 mg/m3 when the subjects left the chamber. In the third part of the experiment,
the subjects were exposed to 6 mg/m3 of CS which was attained over 10 minutes. Symptoms
reported by the subjects included nose and throat irritation, chest burning, sneezing, eye irritation

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and lacrimation, headache, and skin irritation. Three of the four subjects reported that the
exposure was unbearable at 18, 20, and 29 minutes, with chest symptoms being the reason the
subjects left the chamber. The remaining subject was able to tolerate the agent, and the exposure
was terminated at 40 minutes. The investigators attempted to enter the chamber without the
benefit of the gradual increase in exposure concentration, and were unable to remain in the
chamber. In the fourth experiment, a concentration of 6.6 mg/m3 was attained over 30 minutes.
It was noted that the usual signs and symptoms developed, but to a lesser degree. One of the
subjects had to leave after 2 minutes of exposure due to a violent cough, but he returned to the
exposure after his cough had ceased upon exposure to fresh air. He remained in the exposure
chamber for the duration of the 60 minute exposure.

To assess the potential effect of CS exposure on ventilation, cardiac frequency, and breathing
pattern, a group of 11 healthy soldier volunteers was exposed to CS aerosol (particle diameter of
1 micron) at a concentration that was progressively increased from 0.2 mg/m3 up to 1.3 mg/m3
(Cole et al., 1977; Cotes et al., 1972). The exact exposure duration was not provided, but
appeared to be approximately 80 minutes. CS aerosol was produced by saturating the exposure
chamber the evening before the exposure, followed by flushing with air to remove all of the gas
except that adsorbed onto the walls and equipment. During exposure, pyrotechnic generators
were ignited to progressively raise the concentration of CS throughout the exposure session.
Subjects wore woolen or denim battle dress covered with cotton coveralls, boots, and gaiters.
ECG electrodes were applied to the chest, and subjects wore a full respirator into the chamber.
For the commencement of exposure, each subject removed his own respirator. During each
exposure, each subject completed two 8-minute periods of exercise which consisted of cycling at
20W up to 120 W. During exercise, the subjects breathed through an oro-nasal mask and three-
way valve box. Inspiration was from the chamber and expiration was through a 6 L capacity
mixing bottle into a low resistance gas meter. Cardiac frequency was measured using the
electrocardiograph, while a thermister in the valve box recorded respiratory frequency. A
control exposure including exercise was conducted the day before and the day after the exposure
to CS. A major difference between the control and CS exposures was that ventilation was
continued throughout the control session but not the CS exposure session; therefore, the
temperature was much higher in the CS exposure sessions compared to the controls (-24° C vs.
20.5° for controls). When first exposed to the CS aerosol, all subjects experienced intense
discomfort including cough, lacrimation, and substernal pain. Discomfort was severe enough
that two subjects withdrew (one before and one after the first period of exercise), and two
additional subjects were unable to complete the first period of exercise due to coughing. It was
noted that the coughing coincided with ignition of the CS generators. The discomfort
disappeared with continuing exposure. Although cardiac frequency was increased during
exposure to CS compared to control air, the difference was eliminated when the cardiac
frequency was corrected for the increased ambient temperature (corrected to the arbitrary
temperature of 20°C). The ventilation minute volume was reduced from exposure to CS
compared to controls. The reduction appeared to be due to a decrease in respiratory frequency.
The exposure was repeated using 17 volunteers (Cole et al., 1977; Cole et al., 1975). Exposure
conditions were the same with the following exceptions: the CS candles were ignited between
and not during periods of exercise, exposure concentrations were slightly higher (0.92 to 2.15
mg/m3), and the subjects were seen on five consecutive half days sessions of which the first,
third, and fifth sessions were for control observations, and the other two sessions were allocated
one each for exposure to ammonia and to CS (the order of exposure changed between the

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different weeks of the study). Results were generally identical to those observed in the first
study. The only difference was that the reduction in the ventilation minute volume was the result
of a diminution in tidal volume and occurred despite an increase in respiratory frequency.

To investigate the potential for the development of tolerance to CS, a group of 35 healthy
male volunteers was exposed for 60 minutes to increasing concentrations of CS aerosol (Beswick
et al., 1972). Exposures were conducted in a 100 m3 chamber. The chamber was generally
saturated an hour before the exposure, followed by air being blown through the chamber to
remove the CS not absorbed on the walls and equipment. A number of parameters were assessed
before and after exposure, including: a complete medical examination including a chest
radiograph, collection of blood for hematology and clinical chemistry analysis, and respiratory
function tests to assess peak flow, tidal volume, and vital capacity. A total of 10 different
exposure trials were conducted, with no volunteers exposed twice. The exposure concentration
was kept relatively constant for the first three trials (0.56-0.86 mg/m3; 0.71-0.78 mg/m3; 0.31-
0.74 mg/m3, respectively). For the seven remaining trials, exposure concentrations were
increased by a factor of 2, 3, or 4 during the exposure period, with the highest ending
concentration being 2.3 mg/m3 (concentration ranges for the 7 trials were: 0.8-1.4; 0.84-2.3; 0.7-
2; 0.63-2.3; 0.57-2.1; 0.42-1.8; and 0.45-1.7 mg/m3). Chamber concentrations were measured at
10 minute intervals. For the exposures, two to eight volunteers entered the chamber wearing full
respirators and protective coveralls. CS was generated and allowed to mix for 3 minutes before
removal of the respirator. Symptoms from all volunteers were reported during individual
interviews after exposure. One subject left the exposure chamber after 8 minutes of exposure
with complaints of severe stinging of the eyes, throat irritation, cough and dyspnea, salivation,
and nausea, while another left at 55 minutes of exposure due to vomiting. All other subjects
remained in the chamber for the entire 60 minute exposure period. A table summarizing the
symptoms of the exposed individuals is presented in Table 3. The predominant symptoms of
exposure included salivation, eye irritation (stinging, watering), runny nose, and face stinging.
Symptoms generally resolved within 10 minutes of leaving the chamber. To assess the
development of tolerance, two of the trials (group IV in Table 3) consisted of four subjects that
removed the respirator at the start of the exposure (with the CS concentration increasing with
time), while the remaining four subjects did not remove the respirator until the last 5 minutes of
exposure. The subjects that were exposed to CS throughout the entire exposure period were able
to withstand the entire 60 minute exposure (concentrations increasing from 0.84-2.30 and 0.70-
2.00 mg/m3) except for the one individual that had to leave the chamber at 55 minutes due to
vomiting. Of the subjects that removed their respirators the last 5 minutes of exposure, only one
of eight subjects could remain in the chamber for more than one minute; five left within 30
seconds of removing their respirators. No exposure-related changes were observed in
hematology or clinical chemistry parameters. Decreases in heart rate after exposure ceased were
ascribed to the sense of relief each volunteer felt at the finish of an uncomfortable experience,
and the increase in systolic blood pressure observed in individuals when exposure commenced
was due to the abrupt onset of discomfort; continued exposure resulted in normal blood pressure
readings. No abnormalities were noted in measurements of respiratory functions, but it was
noted by the author that the sample size was small and thus may not be representative. It was
concluded that the main effects of CS are due to local irritation of exposed nerve endings, and
any systemic changes noted are due to stress.

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TABLE 3. Symptoms of 34 volunteers exposed to CS aerosol for 60 minutes

Symptoms





Grouping of subjects for assessment of symptoms a







(nominal fold increase in concentration during exposure)



I

n

m

IV

V

Total

Notes



(steady)

(x2)

(x 2)

(x 3) b

(x 4)





Number exposed

5

8

5

8

8

34

-

Eyes: Stinging

5

8

4

7

8

32

No connection between severity and

Watering

5

8

5

7

7

32

conc., but duration may be less with















constant conc.

Nose: Stinging

3

4

1

6

4

18

Effects in nose generally diminished in

Running

3

7

3

8

7

28

subjects except those exposed to CS

Peppery feeling

2

4

2

4

5

17

conc. increasing 3- or 4-fold during

Blocked

1

3

2

3

2

11

exposure period

Mouth: Irritation

2

4

-

6

3

15

Copious production so severe that when

Salivation

5

8

5

8

8

34

subject was spitting, appeared to be















vomiting

Throat: Irritation

4

5

3

6

5

23

-

Dry

-

1

-

6

1

8



Chest: Burning

2

2

-

3

1

8

More severe effects appeared to be

Tight

1

3

2

2

3

11

consequent upon deep breaths which all

Dyspnea

-

2

2

2

3

9

men who held their breath were

Cough

5

2

4

3

4

18

eventually forced to take; coughing was















generally sporadic

Nausea

2

3

1

3

2

11

Likely due to swallowing of large

Vomiting

-

-

-

1

1

2

quantity of saliva; 1 subject in Group V

(during exposure)













vomited within first 5 min and left















chamber but returned to chamber for















duration of exposure; the subject in















Group IV vomited at 55 min of exposure

Face stinging

5

7

5

7

8

32

Appeared to be of shorter duration when















CS conc. remained constant; appeared to















be most unpleasant in shaved regions

Headache

2

1

2

1

-

6

3 persisted throughout exposure; 3 cases















occurred post-exposure; appeared to be















due to irritation of the frontal sinuses

1	Data taken from Beswick et al., 1972

2	a I. 0.78-0.77 mg/m3 (5 exposed)

3	II. 0.56-0.86 mg/m3 (3 exposed); 0.31-0.74 mg/m3 (5 exposed; One volunteer left exposure at 8 min. and is not included)

4	III. 0.8-1.4 mg/m3 (5 exposed)

5	IV. 0.84-2.3 mg/m3 (4 exposed); 0.7-2.0 mg/m3 (4 exposed)

6	V. 0.63-2.3 mg/m3 (2 exposed); 0.57-2.1 mg/m3 (2 exposed); 0.42-1.8 mg/m3 (2 exposed); 0.45-1.7 mg/m3 (2 exposed)

7	b To assess development of tolerance, 4 subjects removed respirators at start of exposure, while the other four removed

8	respirators at the end; the subjects that removed respirators at beginning of exposure were able to withstand the entire 60

9	min. exposure except for one individual that had to leave the chamber at 55 minutes due to vomiting. Of the subjects that

10	removed their respirators the last 5 minutes of exposure, only 1 of 8 could remain in the chamber for more than 1 min., 5

11	five left within 30 sec. of removing their respirators.

12

13	Three groups of volunteers were exposed to various concentrations of CS aerosol to investigate

14	any potential effects of CS exposure on visual acuity (Rengstorff, 1969). The first exposure

15	comprised a group of 10 male volunteers exposed to CS-2 aerosol (CS treated with Cab-o-sil 5

16	and hexamethyldisilaxane) at concentrations of 0.1 to 1.7 mg/m3. The exposure was conducted

17	in a wind tunnel suspended 4.5 feet above the floor; the volunteer sat on a chair at the end of the

18	wind tunnel and put his head through a rubber aperture in the tunnel until he could no longer

19	tolerate the exposure or for a maximum of 10 minutes. A powder dispenser disseminated

20	specific concentrations of CS-2 at a MMD of 0.8 microns into air at a wind speed of 4.5 mph.

21	An Orthorater was used to measure the binocular far and near visual acuity of the subjects before

22	and after exposure. The second and third exposures were to CS aerosol and were conducted in a

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circular steel chamber. CS aerosol (MMD of 0.9 micron) was disseminated from methylene
dichloride solution using a thermal generator, and introduced into the chamber as a uniform
cloud. Subjects wore protective masks for the first five minutes they were in the chamber, and
then removed their masks for the commencement of exposure. The second exposure was
comprised of 34 volunteers, and an Orthorater was again used to measure the binocular far and
near visual acuity before and after exposure. A summary of the amount of time volunteers from
the Exposure 2 group could tolerate exposure to CS is provided in Table 4. The third exposure
comprised 22 volunteers who had a baseline acuity of 20/20 and who could remain in the
exposure chamber for 10 minutes. Binocular acuity was measured using a Snellen visual acuity
projector before, during, and a few minutes after exposure. The Snellen chart contained a row of
20/30, 20/25, and 20/20 letters. No exposure-related changes in visual acuity were noted from
the exposures except those due to the inability of some subjects to keep their eyes open due to
the intense eye irritation. Visual acuity returned to normal for all subjects several minutes after
exposure to CS.

TABLE 4. Summary of exposure time of volunteers: subjects exposed to CS until they

could no longer tolerate the exposure or for a maximum of 10 minutes

Concentration (mg/m3)

Exposure time in seconds



(number of volunteers)

0.4

135(1)



420(1)



435 (1)



600 (4)

0.6

30 (1)



35 (2)



38 (1)



40 (1)



65 (1)



68 (1)



102(1)



105(1)



135(1)



600 (7)

0.9

600 (6)

1.0

35 (1)



40 (1)



45 (1)



50 (1)

Data taken from Rengstorff, 1969

To assess the effect of CS exposure on respiration, a group of six volunteers (four
familiar with CS exposure) were exposed to various concentrations of CS (3 micron ) in a
wind tunnel while a portable breathing device monitored respiration (Craig et al., 1960). The
subjects remained in the tunnel until the exposure became intolerable (see Table 5). Notable
coughing was observed in the subjects exposed to 15 mg/m3 for 61 seconds or to 150 mg/m3
for 12 seconds. Based on the recordings made during exposure, it was concluded that
although the breathing pattern of the volunteers was disrupted, adequate ventilation was
maintained. Therefore, the incapacitation of CS is attributed to the unpleasant sensations of
exposure rather than to any degree of respiratory failure.

TABLE 5. Summary of exposure time of volunteers: sub jects exposed to CS until they

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could no longer tolerate the exposure

Concentration (mg/m3)

Exposure time in seconds

110 +

61 +

15 +

150

12 +

Data taken from Craig et al., 1960
+ Previous experience with CS exposure

A group of 38 U.S. Marines was exposed to a cloud of CS dispersed by a thermal canister as
part of a training exercise to test the ability and speed of the trainees in donning their gas masks
(Thomas et al., 2002). The exposure occurred after six days of strenuous training with minimal
sleep and reduced food consumption, and was followed by a 1.5 mile run. Temperature and
relative humidity at the time of exposure were approximately 24°C and 91%, respectively.
Clinical signs and symptoms began to develop 36-84 hours post exposure during and after
periods of strenuous exercise (one became symptomatic after a 1,000-m pool swim at 36 hours
post exposure; seven became symptomatic after a second swim consisting of a 1000-m open
ocean swim 60 hours post exposure, and one became symptomatic after a third swimming event
of a 1500-m open ocean swim 84 hours post exposure). A total of nine Marines were affected,
with four Marines requiring admission into intensive care. Effects of exposure included dyspnea
upon exertion, hemopytosis (ranging from frank blood to blood-tinged sputum), cough, rales,
reduced arterial blood gas (range of 60-68), and infiltrates visible on chest radiograph. Signs and
symptoms had resolved by 72 hours, and lung function before and after exercise challenge had
returned to normal one week post exposure. An approximate recreation of the exposure with CS
concentrations estimated by air sampling at the same location revealed CS concentrations
ranging from less than quantifiable up to approximately 17 mg/m3.

McDonald and Mahon (2002) propose that the pulmonary symptoms in the Marines
described above by Thomas et al. (2002) were not the result of CS exposure, but rather the result
of water aspiration or swimming induced pulmonary edema (SIPE). The conclusions were based
on the fact that all became symptomatic immediately after swimming, there was a rapid
resolution of symptoms, and there was no evidence of airway dysfunction. Delayed pulmonary
effects of CS exposure are unusual, and there were no other reports of such symptoms in Marines
even though approximately 200,000 Marines have been exposed to CS since 1996 under similar
field conditions.

2.2.2. Case reports

The effects of exposure to CS are generally of an acute nature. However, reactive airways
dysfunction syndrome (RADS) was reported in two individuals exposed to CS. One case
involved a healthy 21-year-old female exposed for 5-10 minutes to CS smoke at a nightclub (Hu
and Christiani, 1992). Immediately following exposure, she exhibited the typical signs and
symptoms of CS exposure including tightness and burning in her chest and coughing. Physical
examination at a hospital and chest radiography were normal, and she was released. She
continued to experience coughing and shortness of breath, and by 4 weeks post exposure, she

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had reduced forced expiratory volume in 1 second (FEVi; 68% of predicted) and forced vital
capacity (78%). Cough and shortness of breath were still present during the 2-year follow-up,
and were made worse by exertion, cold air, and some environmental pollutants. The second case
report described exposure to a riot-control agent containing 1% CS and 1% oleo resin capsicum;
effects of exposure to the capsicum cannot be excluded (Roth and Franzblau, 1996). A healthy
53-year-old male was exposed for at least 30 seconds, and immediately experienced symptoms
of mucous membrane irritation, cough, and chest tightness. Wheezing and shortness of breath
continued for months after exposure, and were severe enough to require hospitalization.
Pulmonary function test results indicated reversible and fixed obstructive pulmonary disease.

A 4-month-old infant exposed to CS for 2-3 hours developed pneumonitis and persistent
leukocytosis (Park and Giammona, 1972). The infant was exposed when a CS tear gas canister
was fired into a house to subdue an adult. Upon hospitalization, the infant had copious nasal and
oral secretions and was sneezing and coughing. A chest X-ray demonstrated that the lungs were
clear, but laboratory testing revealed leukocytosis. The infant developed severe respiratory
distress by the second day of hospitalization, with pulmonary infiltrates evident on X-ray by day
7. The pulmonary infiltration began to decrease on day 15, and the lungs were clear on day 17.
White blood cell counts were elevated throughout hospitalization, finally decreasing when the
patient was discharged from the hospital.

CS is a common riot-control agent in Britain, and there are consequently reports that describe
typical symptoms following exposure to CS in a confined space, such as a night club (Breakell
and Bodiwal, 1998) or bus (Karagama et al., 2003), use by police on individuals for self defense
(Euripidou et al., 2004), or under conditions of large-scale riot control (Anderson et al., 1996;
Himsworth, 1969). Symptoms of exposure included but were not limited to: eye irritation,
lacrimation, blurred vision, burning sensations sometimes accompanied by first degree burns,
cough, headache, shortness of breath, chest pain, sore throat, retching, vomiting, and salivation
(Breakell and Bodiwal, 1998; Karagama et al., 2003; Euripidou et al., 2004; Anderson et al.,
1996; Himsworth, 1969). In general, the symptoms resolved rapidly; however, there were
reports of effects lasting longer that that predicted. It is noted that the hand-held spray canisters
used by the police contain CS dissolved in methyl isobutyl ketone, an industrial solvent and
denaturant (Euripiou et al., 2004; Gray, 2000). It has therefore been proposed that the ketone
combined with the CS may result in more long lasting adverse effects than CS preparations not
containing the solvent.

2.3. Developmental/Reproductive Toxicity

The National Teratology Information Service collected outcome data on 30 pregnant women
who were exposed to CS gas: 12 women during the first trimester, 11 during the second
trimester, and 7 during the third trimester (McElhatton et al., 2004). Acute maternal toxicity
(transient symptoms of ear, nose, and throat irritation) was noted by 50, 82, and 57% of the
exposed women, respectively. Pregnancy outcome was not adversely affected by exposure.

Birth weight was within the normal range except for one female baby weighing less than 2500 g.
Only one infant had a congenital anomaly (hypospadia), and this anomaly has a background
incidence of 1 in 1000 live born male infants. No concentration or duration exposure
parameters were described.

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2.4.	Genotoxicity

No data were located.

2.5.	Summary

CS is a potent irritant, with symptoms of exposure including lacrimation, blepharospasm,
erythema of the eyelids, chest tightness, coughing, nasal irritation and discharge, salivation,
throat irritation, nausea, vomiting (from swallowing excess saliva), and cutaneous irritation
(ranging from stinging to contact irritation or allergic dermatitis). It is reported that an aerosol
concentration of 4 mg/m3 will disperse the majority of rioters within 1 minute, and 10 mg/m3
will deter trained troops (Upshall, 1973). With the exception of more severe cutaneous
reactions, recovery from exposure is generally rapid upon exposure to fresh air, generally within
30 minutes after exposure (Ballantyne, 1977).

Quantitative human inhalation exposure data showing exposure time to intolerance are
summarized in Table 6. Many studies investigated the time to intolerance, which is the time at
which a subject could no longer remain in the atmosphere containing CS and had to leave the
exposure. Tolerance ranged from 5 seconds at 442 mg/m3 to 12-25 seconds at 141 mg/m3 to 9
seconds at 39 mg/m3 to > 90 minutes at 1.5 mg/m3 (Punte et al., 1963; Gutentag et al., 1960).
Tolerance to low concentrations of CS could be increased when exposure occurred under
conditions in which the exposure concentration was increased over time (Punte et al., 1963;
Beswick et al., 1972). A study investigating the differences in respiratory and ocular responses
to different particulate sizes of CS found that small particles are more effective in producing eye
and respiratory irritation, while recovery time from ocular irritation was greater for large
particles (due to the delay in the onset of irritation for the large particles due to the slowness of
the large particle solubility), and recovery time from respiratory irritation was greater for small
particles (smaller sized particles can penetrate further into the respiratory tract) (Owens and
Punte et al., 1963).

Pregnancy outcome was not affected in a prospective case study of 30 pregnant women who
were exposed to CS gas and experienced transient symptoms of ear, nose, and throat irritation
(McElhatton et al., 2004). No other reproductive or developmental toxicity data in humans were
available. Data were not available on repeat-exposure toxicity, genotoxicity, or carcinogenicity.

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TABLE 6. Summary of selected human acute inhalation toxicity/intolerance data

Concentration
mg/m3

Time to
Intolerance
(sec) a

Notes

Reference

94 b
85 c

<60
<60

6 subjects chosen for ability to tolerate CS

Owens and Punte,
1963

5

12
442

53 to > 120

19-43

5

Untrained subjects; duration of exposure was maximum of 2
min.

Punte et al., 1963;
Gutentag et al., 1960

4

10

141

37 to > 120

18-41

12-25

Trained subjects (previous exposure to CS); duration of
exposure was maximum of 2 min.

Punte et al., 1963;
Gutentag et al., 1960

10
13
39

13
13

9

Untrained subjects; exercised before exposure

Punte et al., 1963;
Gutentag et al., 1960

0.4
0.6
0.9
1

135-600 e
30-600 e
600 e
35-50

4 of 7 tolerated 10 min
7 of 17 tolerated 10 min
6 of 6 tolerated 10 min

Rengstorff, 1969

6

(attained over
lOmin)

18 min
20 min
29 min

1 subject
1 subject
1 subject

Punte et al., 1963

0.78

60 min'

5 subjects: all remained in chamber for duration of exposure;
tolerable but caused eye, nose, mouth, and throat irritation,
nausea, chest discomfort, headache, and stinging of the face

Beswick et al., 1972

0.56-0.86
0.31-0.74

8 min
60 minf

9 subjects; conc. | during exp.;

1 subject in 0.31-0.74 group left at 8 min (irritation);
8 subjects tolerated 60 min. exp. w/same signs as 0.78 group



0.8-1.4

60 min'

5 subjects; all tolerated exposure w/ same signs as 0.78 group



0.84-2.3

0.7-2.0

0.63-2.3

0.57-2.1

0.42-1.8

0.45-1.7

60 min'

16 subjects

1 subject vomited at 5 min, left chamber but returned for
duration of exposure;

1 subject vomited at 55 min

14 subjects tolerated 60 min. exp. w/same signs as 0.78
group



1.5

90 min g

Of 4 subjects exposed:

1 developed nose irritation (2 min. into exposure)

3	developed a headache (at 45, 50, and 83 min.)

4	had eye irritation (at 20, 24, 70, and 75 min.)

Punte et al., 1963

a Time at which the subject could no longer tolerate the exposure; duration given in seconds unless otherwise noted
b MMAD of 0.9 microns
c MMAD of 60 microns

e Exposure was for maximum of 10 minutes
f Exposure was for maximum of 60 minutes
8 Exposure was for maximum of 90 minutes

3. ANIMAL TOXICITY DATA
3.1. Acute Lethality

3.1.1. Monkeys

Groups of eight immature male and female Macaca mulatta monkeys (3-4 kg) were exposed
to a cloud of CS dispersed via an M7A3 CS grenade in a 20,000 L chamber at an average CS
concentration of 900 mg/m3 for 3 minutes, 1700 mg/m3 for 5 minutes, 2850 mg/m3 for 10

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minutes, or 2500 mg/m3 for 32 minutes (Striker et al., 1967). It was stated that the cloud was
sampled and measured at various times, but further details were not provided. A group of eight
monkeys served as controls; they were treated similarly to the exposed monkeys except they
were not put into an exposure chamber. Monkeys were observed frequently for clinical signs
during the first 72 hours after exposure. Chest radiographs were taken before exposure and at 2,
6, or 12 hours or 1, 3, 7, or 30 days post exposure. Monkeys were sacrificed at 12 hours or 3, 7,
or 30 days after exposure. Clinical signs in monkeys exposed to 900 mg/m3 for 3 minutes or
1700 mg/m3 for 5 minutes were limited to blinking and a "fright reaction" noted immediately
upon removal from the exposure chamber, quickly disappearing within a few minutes after the
monkeys were moved to fresh air. Monkeys exposed to 2850 mg/m3 for 10 minutes exhibited
frequent blinking, labored respiration, coughing, oral and nasal discharge, occasional vomiting,
and decreased activity and response to external stimuli, with one monkey additionally having
copious eye discharge. The clinical signs were most severe by 12 hours post exposure and were
generally resolved by 72 hours post exposure. Clinical signs in monkeys exposed to 2500 mg/m3
for 30 minutes were severe and included prostration, dyspnea, copious oral and nasal discharge,
and scleral congestion upon removal from the exposure chamber. A total of five monkeys died:
four died three to twelve hours post exposure, and one died at 4 days post exposure. Dyspnea
was most severe at 12 hours, while oral and nasal discharge and effects on the eyes were most
severe by 24 hours post exposure. Radiographic findings were present only in this group, and
included infiltrates that occurred by 3 hours post exposure but were most severe by 24 hours post
exposure, and had cleared by 3 days post exposure.

Pathological examination of the monkeys exposed to 900 or 1700 mg/m3 revealed mild
pulmonary congestion, bronchorrhea, emphysema, and atelectasis within 12 hours post exposure,
a disappearance of these changes at 72 hours post exposure, followed by a recurrence at 7 days
and 30 days post exposure (Striker et al., 1967). Pathological lesions in monkeys exposed to
2850 mg/m3 for 10 minutes were more severe and developed earlier. Pulmonary edema and
congestion and bronchorrhea were present at 12 hours post exposure, progressing to purulent
bronchitis and bronchopneumonia at 72 hours post exposure. At one week post exposure, acute
pleuritis and interstitial pneumonitis were seen, while mucosal lesions and bronchopneumonia
were resolving. Lesions were still present at 4 weeks post exposure, and included emphysema,
atelectasis, and focal interstitial pneumonitis. In the 2500 mg/m3 for 30 minute group,
pathological examination of monkeys that died revealed severe pulmonary edema and
congestion. Of the three surviving monkeys, one monkey each was sacrificed at 3, 7, or 30 days
post exposure. The monkey at 3 days post exposure had considerable edema, but congestion was
less prominent. At 7 days post exposure, emphysema involving all lobes and bronchiolitis were
observed, but most of the edema had cleared. The monkey surviving to 30 days post exposure
had small shrunken lungs, purulent mucoid material filling many small bronchioles, and distinct
bronchiolitis.

McNamara et al. (1969) exposed groups of four monkeys (strain and sex not reported) to 7
different CS concentration-duration combinations. No further experimental details were
available. Mortality data are summarized in Table 7.

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3.1.2. Rats

Groups of ten rats were exposed to an aerosol of CS for exposure durations of 25-90 minutes
(Punte et al., 1962). Animals were exposed in a dynamic inhalation chamber containing
individual cages on racks. Aerosol was generated by passing dry nitrogen through an aspirator.
Molten CS was maintained in a side-armed flask in an oil bath at 140-150°C. The aerosol was
easily generated and liquid droplets recrystalized before entering the exposure chamber.

Chamber concentrations were measured by drawing chamber air through filter paper for
subsequent analysis by spectrophotometry. Samples for particle size determinations were
collected by a Cascade impactor, and mass-median diameter was derived by use of stage
calibrations based on the density of the compound; the particle size was about 1.5 microns (mass
median diameter). Observations for clinical signs were made during and after exposure.
Surviving animals were maintained for 14 days post exposure, at which time they were killed
and subjected to histopathological examination. Immediately after the commencement of
exposure, the animals became excitable and hyperactive, and lacrimation and salivation occurred
within 30 seconds. Lethargy and dyspnea occurred after approximately 5-15 minutes of
exposure. Dyspnea persisted for approximately an hour after exposure ceased, while all other
signs subsided about 5 minutes after removal from the chamber. Histopathological examination
revealed an increase in the number of Goblet cells in the respiratory tract and conjunctiva,
necrosis in the respiratory and gastrointestinal tracts only if particles had impacted the surface,
and an occasional animal with pulmonary edema and hemorrhage in the adrenal glands. The
calculated LCT50 is 32,500 mg min/m3. An unpublished report by McNamara et al. (1969)
appears to provide data additional to those that have been published. Specific study details are
not provided in this report, but one set of study results is consistent with those published by
Punte et al. (1962). The report includes the mortality results of additional animal species
exposed by inhalation to CS, as well as mortality data for CS dispersed by various methods. As
discussed above, Punte et al. (1962) reported mortality data for rats, but the values were reported
only in terms of mg min/m3. Specific concentrations of CS (sprayed as molten agent) with
corresponding exposure durations for these data are reported in McNamara et al. (1969) and are
presented in Table 7.

Groups of 18 male albino SPF rats were exposed to pyrotechnically generated CS smoke in a
10 m3 chamber (Colgrave and Creasey, 1975). The rats were exposed to 5871 ± 476 mg/m3 of
CS for 15 minutes, 6030 ± 590 mg/m3 for 10 minutes, or to 6800 ± 1166 mg/m3 for 5 minutes
(averages and standard deviations calculated using data reported by Colgrave and Creasey;
values were reported by authors as 6000, 6000, and 6400 mg/m3, respectively). The CS was
released from 4 four CS cartridges, each containing 12.5 g CS, 16 g potassium chlorate, 15 g
lactose, and 7.5 g kaolin. The cloud of CS in the exposure chamber was sampled at
approximately one minute intervals for the 10 and 15 minute exposures, and at 30 second
intervals during the 5 minute exposure. The analytical method used to measure CS
concentrations was not described. Survivors were killed at times ranging from 15 minutes to 2
days post exposure. All animals were necropsied, and selected tissues were analyzed by both
light and electron microscope. Non-exposed controls served to establish the typical macroscopic
and microscopic appearance of the particular strain used. Mortality occurred in 4 rats exposed to
5871 mg/m3 for 15 minutes (death occurred by 24 hours post exposure), and in 2 rats exposed to
6030 mg/m3 for 10 minutes (death occurred by 24 and 36 hours post exposure). All animals
exposed to 6800 mg/m3 survived to study termination at 2 days post exposure. Animals that died

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following exposure to CS for 15 minutes developed marked pulmonary congestion with scattered
alveolar hemorrhages and patchy edema. Survivors developed less marked pulmonary
congestion and only occasional areas of edema and hemorrhaging. Rats that died following
exposure to CS for 10 minutes also developed pulmonary congestion, but the severity was much
less than that seen after the 15 minute exposure. Hemorrhages and edema were occasionally
seen in the lungs of survivors. Examination of rats exposed to CS for 5 minutes revealed mild
pulmonary congestion with occasional hemorrhage up to six hours post exposure. Rats killed at
12 hours to 2 days post exposure had no pulmonary findings except for one rat with moderate
and extensive pulmonary congestion. Electron microscopic examination of the lungs from all
exposed rats revealed changes in the epithelium and interstitium, with accumulation of fluid
between the membrane layers and collagen-containing areas of the septum. Degenerative
changes of the epithelium and endothelium led to rupture or dissolution of the capillary wall.
The authors stated that the changes were similar in all exposed rats, with the changes varying
only in the degree of severity. Damage was evident as early as 15 minutes post exposure,
becoming more severe by 30 and 60 minutes post exposure.

Ballantyne and Callaway (1972), exposed groups of male and female Wistar-derived SPF
rats to pyrotechnically generated CS smoke at a concentration of 750 mg/m3 for 30 minutes, 480
mg/m3 for 1 hour, or 150 mg/m3 for 2 hours in a 10 m3 exposure chamber. A group of control
animals was also maintained, but no description of the treatment of the controls was provided
(i.e., if they were exposed under similar conditions to clean air). The grenades used for the
exposure contained CS (2 g), potassium chlorate (2.4 g), lactose (2.4 g), and kaolin (1.2 g).
Although it was stated that the concentration of CS in the exposure chamber was sampled at the
start of the exposure and at 6-minute intervals up to and including 57 minutes, no information
was provided regarding the analytical technique. Groups of animals were sacrificed at 1, 10, and
28 or 29 days post exposure. Additionally, some of the animals exposed to 480 or 150 mg/m3
were retained for up to 32 months to evaluate potential lasting toxicity and pathology (Marrs et
al., 1983a). Animals that died or were sacrificed moribund after one month post exposure and
those sacrificed at the termination of the study at 32 months were subjected to gross necropsy,
and the heart, lungs, small intestine, liver, pancreas, spleen, kidneys, brain, gonads, and pituitary
and adrenal glands were removed and processed for histological examination.

All animals exposed for 30 minutes to 750 mg/m3 survived to the scheduled necropsy, and
histopathological changes were observed only on post exposure day 1 (Table 8). One rat
exhibited congestion of alveolar capillaries and a few scattered alveolar hemorrhages, while
another rat had a few minute foci of renal tubular necrosis at the inner cortex. No pathological
changes were noted in rats at post exposure day 10 or 28. Exposure to 480 mg/m3 for one hour
resulted in the mortality of some rats (Table 10), with the majority of the mortalities occurring
on post-exposure days 1-2. Pathological changes in animals surviving exposure to 480 mg/m3
were generally confined to post exposure day 1. Lesions in rats were limited to minimal
pulmonary congestion and hepatic congestion in one rat, minimal pulmonary hemorrhage and
hepatic necrosis in another rat, and mild pulmonary congestion in a third rat. Two rats showed
mild pulmonary edema. A few rats killed at 10 days had healed lesions as evidenced by
binucleate liver cells around centrilobular veins and immature epithelium in some renal tubules.
No abnormal pathological changes were noted at day 29. Histopathological findings in rats that
died were much more severe and included renal changes (mild to moderate necrosis of the
cortex, moderate to severe necrosis of medulla, and some mild congestion); pulmonary changes

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(mild to severe congestion, mild hemorrhage, and some mild edema) and hepatic changes (a few
rats with mild congestion and mild to moderate necrosis; all rats had livers depleted of
glycogen).

Exposure to 150 mg/m3 for 2 hours resulted in no mortality. Pathological examination of
surviving animals revealed lesions only on Day 1 post exposure. Lesions were confined to
female animals and consisted of one rat with a few scattered alveolar hemorrhages, one rat with
acute mucoid enteritis, and one rat with pneumonic consolidation of the right upper lung lobe.

Exposure to 480 mg/m3 for 1 hour or to 150 mg/m3 for 2 hours did not affect the lifespan of
the rats, and no statistically significant increases were noted in non-neoplastic lesions in the
exposed groups compared to controls (Marrs et al., 1983a). Common non-neoplastic lesions in
male and female rats included changes in the lungs (engorgement, congestion, and inflammatory
changes, pulmonary edema) and pyelonephritis of the kidney. Liver congestion was also a
common finding. No exposure-related neoplastic lesions were evident in male rats. Female rats
in the 150 mg/m3 group exhibited an increased incidence of pituitary tumors; incidence was 26%
for controls, 29% for 480 mg/m3 for 1 hour, and 47% for 150 mg/m3 for 2 hours. The increase
was not statistically significant.

In another experiment, Ballantyne and Callaway (1972) exposed groups of 10 rats for 5 to 20
minutes to an approximate CS concentration of 4000 mg/m3, followed by a 14-day observation
period. An anti-riot grenade containing approximately 50 g of CS was ignited in a 10 m3 static
chamber and allowed to burn to completion. All animals that died and the survivors killed at the
end of the 14-day post exposure period were subjected to gross and histological examination.
Clinical signs during exposure could not be recorded because the aerosol generated in the
chamber resulted in a complete lack of visibility. Upon removal from the chamber, animals
exhibited signs of increased buccal and nasal secretion and dyspnea, particularly at the longer
exposure durations. Mortality data are summarized in Table 9. No animals died during
exposure. Necropsy of animals that died post-exposure revealed pulmonary edema and
congestion, often with multiple, variable sized areas of hemorrhage, and the presence of mucus
in the trachea and major bronchi. Histopathological examination of these animals revealed
severe congestion of the alveolar capillaries and intrapulmonary veins and alveolar hemorrhage.
Mucus was seen in some bronchi and bronchioles, and occasional areas of collapse and
hemorrhage were seen distal to a completely occluded bronchiole. Moderate to marked
pulmonary edema was also observed in several animals. No evidence of acute inflammatory cell
infiltrate was observed in any of the lungs examined, suggesting that the CS aerosol produced
direct injury to the pulmonary capillary endothelium. Circulatory failure evidenced as
congestion of the liver, kidney, and spleen and dilation of the right ventricle was present in most
of the animals that died. Animals that survived to 14 days post exposure did not have any
residual pathology at necropsy.

Groups of twenty or twenty-one male Porton-Wistar rats were exposed by whole body
inhalation to various concentrations of CS aerosol for durations of 10- to 60-minutes (Table 10)
(Ballantyne and Swantson, 1978). Animals were exposed in a 1 m3 dynamic flow chamber. The
aerosol was generated by filling a Collision spray with molten CS (heated to 150°C) and passing
pure nitrogen into the air stream. The resultant aerosol was fed into the diluting air stream.
Chamber atmosphere was sampled for one minute at five minute intervals by aspirating air
through glass fiber discs held in double cone filters. A bubbler containing hydrochloric acid in

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ethanol was connected in line to the glass filter to act as an additional trap. The contents of the
bubbler were used to elute CS from the filter discs, and the concentration of CS in the resultant
extract was measured by absorption spectrophotometry and compared against a prepared
standard. Signs of toxicity included increased nasal and buccal secretions and increased rates of
respiration upon removal from the chamber, which disappeared within approximately one hour
post exposure. No animals died during exposure; deaths generally occurred within the first two
days following exposure. A summary of mortality data is presented in Table 10. Necropsy
findings in animals dying within 48 hours post exposure included pulmonary congestion and
edema (with some animals also having multiple variable sized hemorrhages) and congestion of
the trachea. Moderate amounts of mucus were also seen in the trachea. Histopathological
examination of the lungs from these animals revealed moderate to marked congestion, inter- and
intra-alveolar hemorrhaging, and excess secretions in the bronchioles and intrapulmonary
bronchi. Examination of animals dying after 48 hours revealed similar findings with additional
findings of early bronchopneumonia. Congestion of the liver, kidney, spleen, and small
intestines were also frequently seen in animals dying from exposure. No abnormal findings were
noted in animals surviving 14 days post exposure.

3.1.3. Mice

Groups of twenty mice were exposed to an aerosol of CS for exposure durations of 10-60
minutes (Punte et al., 1962). Experimental procedures, clinical signs, and necropsy results are
similar to those described for rats in Section 3.1.2. The calculated LCT50 is 43,500 mg min/m3.
An unpublished report by McNamara et al. (1969) appears to provide data additional to those
that have been published. Specific study details are not provided in this report, but one set of
study results is consistent with those published by Punte et al. (1962). The report includes the
mortality results of additional animal species exposed by inhalation to CS, as well as mortality
data for CS dispersed by various methods. As described above, Punte et al. (1962) reported
mortality data for mice, but the values were reported only in terms of mg min/m3. Specific
concentrations of CS (sprayed as molten agent) with corresponding exposure durations for these
data are reported in McNamara et al. (1969) and are presented in Table 7.

Ballantyne and Callaway (1972) exposed groups of 10 mice for 5 to 20 minutes to an
approximate CS concentration of 4000 mg/m3, followed by a 14-day observation period. The
experimental protocol, clinical signs, and necropsy findings are similar to those described in the
rat study (Section 3.1.2). Mortality data are summarized in Table 9.

Groups of nineteen to forty male albino mice were exposed by whole body inhalation to
various concentrations of CS aerosol for durations of 15- to 30-minutes (Table 10) (Ballantyne
and Swantson, 1978). Experimental protocol, clinical signs, and necropsy findings are as
described for the rat study in Section 3.1.2. Mortality data are summarized in Table 10.

3.1.4. Guinea Pigs

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Groups of ten guinea pigs were exposed to an aerosol of CS for exposure durations of 5-40
minutes (Punte et al., 1962). Experimental procedures, clinical signs, and necropsy results are
similar to those described for rats in Section 3.1.2. The calculated LCT50 is 8,300 mg min/m3.
An unpublished report by McNamara et al. (1969) appears to provide data additional to those
that have been published. Specific study details are not provided in this report, but one set of
study results is consistent with those published by Punte et al. (1962). The report includes the
mortality results of additional animal species exposed by inhalation to CS, as well as mortality
data for CS dispersed by various methods. As described above, Punte et al. (1962) reported
mortality data for guinea pigs, but the values were reported only in terms of mg min/m3.

Specific concentrations of CS (sprayed as molten agent) with corresponding exposure durations
for these data are reported in McNamara et al. (1969) and are presented in Table 7.

Ballantyne and Callaway (1972) exposed groups of five guinea pigs for 5 to 20 minutes to an
approximate CS concentration of 4000 mg/m3, followed by a 14-day observation period. The
experimental protocol, clinical signs, and necropsy findings are similar to those described in the
rat study (Section 3.1.2). Mortality data are summarized in Table 9.

Groups of ten to twenty female Dunkin Hartley guinea pigs were exposed by whole body
inhalation to various concentrations of CS aerosol for durations of 10- to 45-minutes (Table 10)
(Ballantyne and Swantson, 1978). Experimental protocol, clinical signs, and necropsy findings
are as described for the rat study in Section 3.1.2. Mortality data are summarized in Table 10.

3.1.5. Rabbits

Groups of four rabbits were exposed to an aerosol of CS for exposure durations of 30-90
minutes (Punte et al., 1962). Experimental procedures, clinical signs, and necropsy results are
similar to those described for rats in Section 3.1.2, except that hyperactivity, salivation, and
lachrymation were not reported. The calculated LCT50 is 17,000 mg min/m3. An unpublished
report by McNamara et al. (1969) appears to provide data additional to those that have been
published. Specific study details are not provided in this report, but one set of study results is
consistent with those published by Punte et al. (1962). The report includes the mortality results
of additional animal species exposed by inhalation to CS, as well as mortality data for CS
dispersed by various methods. As described above, Punte et al. (1962) reported mortality data
for guinea pigs, but the values were reported only in terms of mg min/m3. Specific
concentrations of CS (sprayed as molten agent) with corresponding exposure durations for these
data are reported in McNamara et al. (1969) and are presented in Table 7.

Ballantyne and Callaway (1972) exposed groups of five rabbits for 5 to 20 minutes to an
approximate CS concentration of 4000 mg/m3, followed by a 14-day observation period. The
experimental protocol, clinical signs, and necropsy findings are similar to those described in the
rat study (Section 3.1.2). Mortality data are summarized in Table 9.

Groups of five to ten female New Zealand white rabbits were exposed by whole body
inhalation to various concentrations of CS aerosol for durations of 5- to 60-minutes (Table 10)
(Ballantyne and Swantson, 1978). Experimental protocol, clinical signs, and necropsy findings
are as described for the rat study in Section 3.1.2. Mortality data are summarized in Table 10.

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3.1.6. Hamsters

Ballantyne and Callaway (1972), exposed groups of male and female golden hamsters once
to pyrotechnically generated CS smoke at a concentration of 750 mg/m3 for 30 minutes, 480
mg/m3 for 1 hour, or 150 mg/m3 for 2 hours in a 10 m3 exposure chamber. The experimental
protocol is identical to that discussed for rats in section 3.1.2.

All animals exposed for 30 minutes to 750 mg/m3 survived to the scheduled necropsy, and
histopathological changes were observed only on post exposure day 1 (Table 10). Three
hamsters exhibited a few scattered alveolar hemorrhages, with one of these hamsters also having
congestion of alveolar capillaries. No pathological changes were noted at post exposure day 10
or 28. Exposure to 480 mg/m3 for one hour resulted in the mortality of some hamsters (Table
10), with the majority of the mortalities occurring on post-exposure days 1-2. Pathological
changes in animals surviving exposure to 480 mg/m3 were generally confined to post exposure
day 1. Pathological changes included eight hamsters with mild pulmonary congestion with four
of these hamsters also exhibiting mild pulmonary hemorrhage. A hamster with no lung lesions
had mild renal congestion and necrosis in the medulla, while another had only mild necrosis in
the medulla. A few hamsters killed at 10 days had healed lesions as evidenced by binucleate
liver cells around centrilobular veins and immature epithelium in some renal tubules. No
abnormal pathological changes were noted at day 29. Histopathological findings in hamsters
that died were generally similar to those in rats (section 3.1.2); however, the lesions were less
severe in hamsters than in rats.

Exposure to 150 mg/m3 for 2 hours resulted in the mortality of 2 male hamsters (Day 12 or
16), and necropsy revealed bronchopneumonia. Pathological examination of surviving animals
revealed lesions only on Day 1 post exposure. Lesions were confined to female animals and
consisted of one female with a few scattered alveolar hemorrhages and 2 females with a few
scattered foci of acute renal tubular necrosis at the inner cortex.

Exposure to 480 mg/m3 for 1 hour or to 150 mg/m3 for 2 hours did not affect the lifespan of
the hamsters, and no statistically significant increases were noted in non-neoplastic lesions in the
exposed groups compared to controls (Marrs et al., 1983a). Common non-neoplastic lesions in
male and female hamsters included changes in the lungs (engorgement, congestion, and
inflammatory changes, pulmonary edema) and pyelonephritis of the kidney. No exposure-
related neoplastic lesions were evident in male or female hamsters.

3.1.7. Dogs

McNamara et al. (1969) exposed groups of four dogs (strain and sex not reported) to 8
different CS concentration-duration combinations. No further experimental details were
available. Mortality data are summarized in Table 7.

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1	Following a 30-second exposure to 25 mg/m3 of CS, a dog exhibited increased blood

2	pressure, altered respiratory pattern, tachycardia, and increased femoral artery blood flow

3	(Cucinell et al., 1971). In another exposure, two dogs were exposed for 23 minutes to 2600

4	mg/m3 of CS. One dog survived, while the other dog died 52 hours post exposure. It was noted

5	that following exposure to a lethal dose of CS, dogs recover partially, but then develop

6	respiratory distress and die 48-70 hours post exposure.

7

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2

3

4

5

6

7

8

9

10

11

12

13

14

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TABLE 7. Mortality data in rats, mice, guinea pigs, rabbits, dogs, and monkeys following inhalation exposure

to CS aerosol

Species

Concentration
(mg/m3)

Duration (min)

Mortality

Time to death (days) a

Rats b

560

25

1/10

KD

543

35

2/10

1(2)

489

45

3/10

2(1), 3(1), 4(1)

454

55

5/10

1 (3), 3(2)

500

60

2/10

1(2)

500

80

6/10

1(1), 2(2), 6(3)

500

90

8/10

1(1), 3(2), 7(2), 11(3)

Mice b

1200

10

0/20



1100

20

7/20

7(1), 8(3), 9(3)

900

30

2/20

7(2)

800

40

5/20

5(2), 9(3)

740

50

5/20

5(1), 6(3), 7(1)

683

60

14/20

5(4), 8(5), 9(4), 13(1)

Guinea pigs b

400

5

1/10

7(1)

400

10

2/10

7(1), 8(1)

400

15

4/10

1(2), 6(2)

500

20

3/10

1(1), 6(1), 7(1)

400

25

7/10

2(5), 7(1), 8(1)

400

30

7/10

1(4), 5(1). 7(1), 9(1)

425

40

8/10

1(7), 3(1)

Rabbits b

500

30

1/4

6(1)

250

40

0/4

-

267

45

0/4

-

250

80

3/4

1(1), 2(1), 7(1)

333

90

4/4

1(1), 2(1), 3(1), 8(1)

Dogs c

833

20

0/4

-

649

30

1/4

12(1)

508

36

2/4

5(1), 10(1)

899

40

2/4

1(1), 2(1)

520

45

2/4

1(1), 4(1)

612

45

2/4

1(2)

797

60

3/4

1(2), 3(1)

909

60

2/4

1(2)

Monkeys c

469

24

1/4

5(1)

673

30

2/4

1(2)

381

45

2/4

1(2)

612

45

1/4

KD

699

60

1/4

KD

941

60

3/4

1(3)

1057

60

2/4

1(2)

Data taken from McNamara et al., 1969

a Number in parenthesis indicates number of animal deaths on that day
b Source of CS the same

c Source of CS the same; except monkey exposure had MMD=2.0-3.2 |x; stated that u.v. analysis conducted at 260 m|x

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TABLE 8. Summary of acute toxicity data in rats and hamsters

Cone.

Time

Species

Sex

No.

No. of

Animals Killed

(mg/m3)

(min)





Exposed

Deaths

Day 1

Day 10

Day 25 or 29











(%)

No.
killed

No. w/
lesions

No.
killed

No. w/
lesions

No.
killed

No. w/
lesions

750

30

Hamster

M

24

0

8

3

8

0

8

0





Rat

M

24

0

8

2

8

0

8

0

480

60

Hamster

M

47

16 (34)

8

4

2

0

9

0







F

59

15(25)

7

6

3

0

8

0





Rat

M

60

6 (10)

6

2

2

0

8

0







F

60

3 (3)

7

1

2

0

8

0

150

120

Hamster

M

58

2(3)

8

0

6

0

6

0







F

62

0

8

3

10

0

8

0





Rat

M

60

0

8

0

8

0

8

0







F

60

0

8

2

8

1

8

0

1	Data taken from Ballantyne and Callaway, 1972

2

3

4

5

TABLE 9. Summary of mortality of guinea pigs, rabbits, rats, and mice exposed to CS

Cone, (mg/m3)

Exp.
Duration
(min)

Mortality (No. died/No. ex

posed)

Rat

Mouse

Guinea pig

Rabbit

3950

5

0/10

1/10

1/5

0/5

4760

5

0/10

0/10

0/5

0/5

4250

10

1/10

0/10

5/5

0/5

4330

10

1/10

4/10

3/5

2/5

4150

15

0/10

3/10

3/5

2/5

5167

15

7/10

3/10

5/5

2/5

4000

20

9/10

8/10

5/5

4/5

4300

20

8/10

6/10

5/5

5/5

6	Data taken from Ballantyne and Callaway, 1972

7

8

9

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3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

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TABLE 10. Summary of mortality data in rats, rabbits, and guinea pigs followin

g inhalation exposure to CS

Species

Average
Concentration
(mg/m3)

Duration
(min)

Mortality
(No died/No.
exposed)

% Mortality

LCT50 (mg min/m3 ± 95%)

Rat (male)

1802

10

0/20

0

88,480 (77,370-98,520)

1806

45

8/20

40

1911

45

9/20

45

2629

60

20/21

95

2699

60

20/20

100

Mouse (male)

1432

15

1/40

3

2753

20

17/40

43

50,010 (42,750-60,220)

2333

30

10/19

53

2400

30

17/40

43

2550

30

24/36

67

Guinea pig
(female)

2326

10

2/20

10

67,200 (59,200-78,420)

2380

15

2/10

20

1685

25

10/20

50

2310

20

8/20

40

1649

30

11/20

55

1302

45

9/11

82

2041

30

13/20

65

2373

30

10/19

53

Rabbit
(female)

846

5

0/10

0

54,090 (42,630-70,400)

836

10

0/10

0

1434

10

0/10

0

1802

10

1/5

20

2188

15

2/10

20

2380

15

3/8

38

1407

30

4/10

40

1653

30

2/10

20

1309

45

4/5

80

2118

45

9/10

90

2133

60

7/8

88

3066

60

8/9

89

Data taken from Ballantyne and Swantson, 1978

3.2. Nonlethal Acute Toxicity

3.2.1.	Mice

AnRDso of 4.0 mg/m3 (95% C.I.: 3.3-5.2 mg/m3) (reported as: 0.52 ppm; 95% C.I.: 0.429-
0.677 ppm) was reported for male Swiss-Webster mice (Kane et al., 1979).

3.2.2.	Rabbits

To investigate whether CS exposure can cause diarrhea, four rabbits were exposed to
thermally-generated pure CS in a 10 m3 chamber (Ballantyne and Beswick, 1972). The
exposures were as follows: one rabbit each was exposed to 58 mg/m3 for 30 minutes, 46 mg/m3
for 20 minutes, 54 mg/m3 for 12 minutes, or 17 mg/m3 for 17 minutes. Animals were placed
singly in cages with removable trays lined with several layers of filter paper arranged to collect

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stool samples. The number of stool pellets passed, their total weight, and water content were
recorded for several day before and after exposure. Exposure to CS did not result in an increased
incidence of diarrhea.

Two rabbits were exposed in a static chamber to the entire contents of a 3 ounce unit
containing 71.5 grams of CS (Gaskins et al., 1972). The unit required 20 seconds to fully
dispense. Both rabbits became unconscious after approximately two minutes of exposure and
were moved to fresh air. The rabbits had regained their righting reflex approximately 10-20
minutes post exposure and were almost completely recovered by one hour post exposure, with
the only effect still visible being moderate eye wetness. Gross necropsy of the rabbits two weeks
post exposure did not reveal any abnormalities. Another two rabbits were exposed to 23.2 g of
CS during dispersion of a CS unit requiring about ten seconds to completely discharge. The
dispensed CS formed a cloud in the chamber. The rabbits tried to avoid the spray as it was
dispensed, and then sat quietly with their eyes tightly closed for the remainder of the five minute
exposure. No abnormalities were observed in the eyes or skin of the exposed rabbits.

3.3. Repeat Dose Studies

3.3.1. Rats

Groups of five male and five female F344/N rats were exposed to CS2 concentrations of 0,
1, 3, 10, 30, or 100 mg/m3 for 6 hours/day, 5 days/week for 2 weeks (NTP, 1990). (CS2 contains
94% CS, 1% hexamethyldisilizane, and 5% Cab-o-Sil®). All rats exposed to 30 or 100 mg/m3
died before study termination. Rats from all CS2 exposure groups exhibited adverse clinical
signs, ranging from erythema and blepharospasm at the lower concentrations and progressing to
dacryorrhea, mouth breathing, listlessness, and mouth breathing at the high concentrations. Rats
in the 1 mg/m3 group gained more weight over the exposure period compared to controls, but
generally decreased body weight was noted at exposure concentrations of 3 mg/m3 and higher.

Groups of ten male and ten female F344/N rats were exposed to 0, 0.4, 0.75, 1.5, 3, or 6
mg/m3 of CS2 6 hours/day, 5 days/week for 13 weeks (NTP, 1990). One male rat exposed to 6
mg/m3 died; all others survived to study termination. Clinical signs of eye irritation (partial or
complete eyelid) were noted in all CS2 exposure groups, and rats exposed to 6 mg/m3 of CS2
developed erythema of the extremities that persisted overnight. Rats exposed to 1.5 mg/m3 and
higher gained significantly less weight over the study period compared to controls; final mean
body weight was 17-44% lower than that of controls for males and 10-24%> lower for females.
An approximate 46%> reduction in thymus weight relative to body weight was noted in male and
female rats exposed to 6 mg/m3. Concentration-related histopathological changes included focal
erosion with regenerative hyperplasia and squamous metaplasia of the respiratory epithelium.
Acute inflammation and hyperplasia of the respiratory epithelium were also noted.

One group of 56 male rats was exposed for five minutes/day for five days to a mean CS
concentration of 1470 or 1770 mg/m3, while another group of 49 male rats was exposed for 80
minutes/day for nine days to a mean CS concentration of 12.5 or 14.8 mg/m3 (Ballantyne and
Callaway, 1972). Exposures to the thermally-generated CS aerosol (mass mean diameter of 1-2

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|im) were conducted in a 1 m3 chamber, with chamber air sampled continuously throughout
exposure at a rate of 1 liter per minute using a double cone filter. The samples were analyzed for
CS content (further details not provided). Groups of 3-5 survivors were sacrificed at 1, 6, and 24
hours and 2, 3, 4, 5, 7, 10, 14, and 21 days after the final exposure, and subjected to gross and
microscopic examination. All animals survived the 5-minute exposures. Histopathological
examination revealed minimal congestion of the alveolar capillaries at one or six hours post
exposure in 2/5 rats; a few scattered alveolar hemorrhages at two days post exposure in 1/4 rats;
and scattered patches of bronchopneumonia at 7, 8, 10, and 18 days post exposure in 1/5, 1/3,
1/3, and 2/5 rats, respectively. Pathological changes in control rats included scattered alveolar
hemorrhages in 2/11 rats, and subacute mucoid enteritis in 1/11 rats. Five of the 49 rats exposed
for 80 minutes/day to 12.5 or 14.8 mg/m3 died: one after the 7th exposure, two after the 8th
exposure, and two died five days after the final exposure. Necropsy revealed widespread acute
bronchopneumonia. Histopathological examination of the surviving animals revealed lesions up
to five days post exposure; no lesions were reported in rats examined after five days post
exposure.

3.3.2. Mice

Groups of five male and five female B6C3Fi mice were exposed to CS2 concentrations of 0,
1, 3, 10, 30, or 100 mg/m3 for 6 hours/day, 5 days/week for 2 weeks (NTP, 1990). All mice
exposed to 10 mg/m3 and greater died before study termination. Mice from all CS2 exposure
groups exhibited adverse clinical signs, ranging from erythema and blepharospasm at the lower
concentrations and progressing to dacryorrhea, mouth breathing, listlessness, and mouth
breathing at the high concentrations. Mice exposed to 1 mg/m3 gained more weight over the
exposure period compared to controls, but generally lost body weight at exposure concentrations
of 3 mg/m3 and higher.

Groups of ten male and ten female B6C3Fi mice were exposed to 0, 0.4, 0.75, 1.5, 3, or 6
mg/m3 of CS2 6 hours/day, 5 days/week for 13 weeks (NTP, 1990). All mice exposed to 6
mg/m3 died and 1 male and 1 female mouse from the 3 mg/m3 group died during the second
week of exposure. The clinical signs of closed or partially closed eyes during exposure were
noted in mice from all exposure groups through week 6, with the mice exposed to 3 mg/m3 again
exhibiting eye closure during weeks 12 and 13. Concentration-related decreases in body weight
compared to controls were noted in all exposure groups; final mean body weights of mice in the
3 mg/m3 group were 13% lower for males and 9% lower for females. Exposure-related
histopathological changes were observed in mice exposed to 1.5 mg/m3 and higher and included
focal inflammation and squamous metaplasia (primarily in the nasal turbinates) and
inflammation of the vomeronasal organ.

3.3.3 Rats, Mice, Guinea Pigs, Rabbits

Groups of 5-10 guinea pigs, 5 rabbits, 10 rats, and 10-20 mice were exposed for 5 hours/day for
1 to 7 successive days to an approximate CS concentration of 30-40 mg/m3 (Ballantyne and
Callaway, 1972). For the exposure, an anti-riot grenade containing 0.5 to 0.75 g CS was ignited
every 30 minutes in a 10 m3 static chamber to maintain the nominal concentration. The authors
stated that concentrations were determined by continuous sampling throughout the animal

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exposure, but no other details were provided. Animals were removed to fresh air following each
exposure, and were maintained for a 14-day post exposure period after their last exposure. All
animals that died and the survivors killed at the end of the 14-day post exposure period were
subjected to gross and histological examination. A summary of the mortality data is presented in
Table 11. The description of clinical signs was limited to a statement that rabbits and rats
exhibited more rhinorrhea and lacrimation than did mice, while guinea pigs showed few clinical
signs apart from occasional sneezing during the first hour of exposure. Necropsy of animals that
died revealed moderate to marked congestion of the alveolar capillaries and intrapulmonary
veins and inter- and intra-alveolar areas of hemorrhage, and many of the animals that died also
had congestion of the liver, kidney, and small intestine. Moderate pulmonary edema was noted
in a "few of the animals." No residual pathology was noted in animals that survived to study
termination.

TABLE 11. Summary of mortality of guinea pigs, rabbits, rats, and mice exposed to CS for 5 h/day for up to 7

days

Species

Duration

Cone.

Mortality

hr/day

No. days

(mg/m3)

(No. died/No. exposed)

Guinea pig

44.7

0/5

36.0

2/5

34.2

3/10

35.2

2/5

43.7

10/10

Rabbit

36.0

1/5

34.2

2/5

Rat

37.0

1/10

36.0

9/10

34.2

7/10

Mouse

40.0

0/10

38.8

0/10

36.0

1/10

31.9

10/10

56.4

16/20

Data taken from Ballantyne and Callaway, 1972

3.4. Developmental/Reproductive Toxicity

Groups of 22-24 pregnant Porton strain rats or 12 pregnant New Zealand White rabbits were
exposed to CS aerosol for 5 minutes/day over GDs 6-15 or GDs 6-18, respectively, and were
sacrificed on GD 21 or GD 30, respectively (Upshall, 1973). CS aerosol with a particle size of
l-2|im was generated by melting pure crystalline CS at 120°C using a Collison spray. A
preliminary study investigated exposure to 0 or 20 mg/m3 CS, followed by a subsequent
concentration-response study at concentrations of 0, 6, 20, or 60 mg/m3. Rat controls were
recaged and moved out of their normal environment during the test group exposure, while rabbit
controls were exposed to a siliconized silica aerosol at 60 mg/m3. Additional control groups of
pregnant rats were exposed to a particulate aerosol (60 mg/m3 of Neosil) or to water aerosol to
evaluate the stress of aerosol exposure. At sacrifice, cesarean section was performed, and
fetuses were evaluated for skeletal or visceral abnormalities. In addition, the lungs, liver,
kidneys, and adrenal from the rabbit dams in the concentration-response study were evaluated
histologically. No definitive effects of treatment were noted. In the preliminary rat study,

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exposed rats exhibited a decrease in maternal weight gain compared with controls (-23%), but a
clear concentration-response was not observed in the main study (-23%, -12%, and 15% for the
6, 20, or 60 mg/m3 groups, respectively). Fetal weight appeared to decrease with increasing
concentration in the main rat study (3.3, 3.2, and 3.1 g, respectively, vs. 3.5 for controls), but the
fetal weights were comparable to the rat fetal weights recorded in other studies. No other
statistically significant effects were observed. No exposure-related effects were noted in
exposed rabbits or their offspring. Although the exposure concentrations were sufficient to
cause extreme irritation, clinical signs in exposed rats and rabbits were not reported.

3.5. Genotoxicity

In general, CS was not mutagenic to Salmonella typhimurium. Mutations were not induced
with or without the presence of S9 at CS concentrations of 12.5-800 [xg/plate in strains TA97a,
TA98, TA100, TA102, or TA104 (Meshram et al., 1992); of up to 1.5 mg/plate in strains TA98,
TA100, TA1535, TA1537 (Wild et al., 1983); of 10 [xg/plate up to 2 mg/plate in strains TA98,
TA1535, TA1537, or TA1538 (Daniken et al., 1981); or at CS2 concentrations of 3.3-333
[xg/plate in strains TA98, TA100, TA1535, or TA1537 (NTP, 1990). Equivocal responses for CS
and CS2 were reported in strain TA100 only without S9 (Daniken et al., 1981; NTP, 1990), and
for CS2 in strain TA97 but only with 30% S9 (NTP, 1990). Cytotoxicity was observed starting
at doses of 200 [xg/plate, but the presence of 30% S9 generally reduced the cytotoxicity.

Other in vitro genotoxicity testing was generally positive. CS induced sister chromatid
exchanges (SCE) and chromosomal aberrations in Chinese hamster (CHO) ovary cells both with
and without S9 at CS2 concentrations of 6 [xg/mL and greater (NTP, 1990). Trifluorothymidine
resistance in mouse L5178Y lymphoma cells was induced in the absence of S9 at a CS
concentration of 2.5 [xg/mL (McGregor et al., 1988; NTP, 1990). V79 Chinese hamster cells
exposed to 19, 38, or 75 [xM of CS in culture for 3 hours and evaluated 6 days later showed
reduced survival (by ~ 20, 30, and 80%, respectively; values are read off of graph), and exhibited
a concentration-related increase in the frequency of mutants resistant to 6-thioguanine (mutations
induced approximately 4 to 5-fold above controls at the highest concentration) (Ziegler-
Skylakakis et al., 1989). Exposure to CS also increased the frequency of micronuclei by
approximately 2-fold at 19 [xM of CS up to 18-fold at 75 [xM of CS as measured 24 hours after
exposure, but did not induce DNA repair synthesis as assessed using the BrdUrd density-shift
method. A concentration-dependent increase was observed in spindle cell disturbances,
particularly C-metaphases (chromosomes completely scattered in cytoplasm and often highly
contracted), when cells were exposed to 5, 9, 19, or 38 [xM of CS for three hours (Schmid and
Baucher., 1991). The C-mitotic effect was also reflected in the appearance of a metaphase block
and the disappearance of other mitotic figures (prophases, ana-telophases). When a differential
staining technique was applied to allow for visualization of the spindle apparatus and
chromosomes, a concentration-dependent increase in the number of mitoses with abnormal
spindles was again observed, particularly apolar mitoses (mitotic figures without any signs of
polar spindle configurations) (Salassidis et al., 1991). Further investigation into the mechanism
of CS-induced c-mitotic spindle damage found that exposure of cells to 38 [xM of CS for 20
hours or 3 hours followed by 20 hours of recovery resulted in an increase in the number of
aneuploid cells and in the polyploid index (Schmid and Bauchinger, 1991). The number of
aneuploid cells and the polyploid index were increased to a much greater extent by exposure to
the metabolite o-chlorobenzaldehyde as compared to CS, suggesting that this metabolite may

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play a role in the induction of spindle damage. A comparison of the effectiveness of various
exposure conditions revealed that cells exposed to CS at concentrations of up to 38 [xM for 20
hours exhibited a concentration-dependent increase in the number of S-cells and the frequency of
chromatid-type aberrations (single breaks, isolocus breaks and exchanges, and gaps); exposure
for 3 hours followed by a 20-hour recovery period resulted in similar effects but was not as
effective; and no effects were observed when cells were incubated with the supernatant from the
3 hour exposure (Bauchinger and Schmid, 1992). It is noted that the cell cycle time of the V79
cell line used is approximately 8-10 hours; therefore, the cells had time to run through one or two
S-phases.

Genotoxicity testing in vivo was generally negative. CS did not bind to DNA in the liver or
kidneys of rats i.p. injected with 13 mg/kg of radiolabeled CS and evaluated 8 or 75 hours after
dosing, but did bind to nuclear proteins in these organs (Dankien et al., 1981). CS did not cause
an increase in sex-linked recessive mutations in germ cells of male Drosophila when
administered in the feed at concentrations of 5 x 10"4M to 2.6 x 10"3 M for three days (Wild et
al., 1983), and did not increase micronucleated polychromatic erythrocytes in the bone marrow
of NMRI mice administered CS by intraperitoneal injection of 19 or 38 mg/kg or by oral
administration of 113 or 226 mg/kg (Wild et al., 1983). It is noted that the oral dose of 226
mg/kg killed 10 of 13 exposed mice.

3.6. Chronic Toxicity/Carcinogenicity

Groups of fifty B6C3Fi mice and fifty F344/N rats/sex were exposed for 6 hours/day, 5
days/week for 105 weeks to target CS2 concentrations of 0, 0.75, or 1.5 mg/m3 (mice) or 0,
0.075, 0.25, or 0.75 mg/m3 (rats) (NTP, 1990). Rats exposed to 0.75 mg/m3 of CS2 developed
histopathological changes in the respiratory and olfactory epithelium of the nasal passage and
inflammation and proliferation of the periosteum of the turbinate bones. No neoplastic effects
were present. Lesions seen in the nasal cavity of exposed mice included inflammation in the
anterior middle portions of the nasal passage, and focal hyperplasia and/or squamous metaplasia
of the respiratory epithelium. No other adverse effects of exposure were noted. Female mice
exhibited a statistically significant, exposure-related reduction in the incidences of hyperplasia
and adenomas of the pituitary gland pars distalis (rates of the adenomas in the 0, 0.75, and 1.5
mg/m3 groups: 16/47, 5/46, and 1/46, respectively). Lymphomas in female mice also occurred
with a significant negative trend (21/50, 12/50, and 8/50, respectively).

Groups of 75 male SPF Porton strain mice, 50 male Porton Wistar derived rats, and 50
Dunkin Hartley guinea pigs were exposed to nominal concentrations of 0, 3, 30, or 300 mg/m3
CS aerosol (mass mean diameter of 3-4 |im) for 1 hour/day, 5 days/week for up to 55 exposures
(11 weeks) in mice and up to 120 exposures (24 weeks) in rats and guinea pigs (Marrs et al.,
1983b). Exposure to the high concentration resulted in excessive mortality in mice and guinea
pigs within days of the start of exposure; therefore, exposure to the high concentration was
discontinued after three exposures in mice, and after five exposures in rats and guinea pigs (the
actual mortality at days 3 and day 5, respectively, were not provided) (Marrs et al., 1983b).
During the first month of the experiment, 17% of the mice and 46% of the guinea pigs exposed
to the high-concentration died. Mice exhibited a significant trend (p<0.001) in the incidence of
early death with concentration of exposure. The authors also reported a significant trend

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(p<0.001) in the incidence of early death with concentration of exposure in guinea pigs;
however, most of the mortality in guinea pigs occurred during the first month. Post mortem
examination of ten guinea pigs that died during exposure revealed acute alveolitis in seven of the
animals, with mild alveolitis present in the other three examined. The cause of death in mice
dying during exposure could not be determined. The author noted that toxic signs were not
usually observed: death occurred suddenly and without warning. No cause of death could be
ascribed to animals that died during the observation period. CS exposure did not affect the
growth of rats or guinea pigs, but did result in a concentration-related decrease in the growth of
mice. No definitive, exposure-related histological findings were observed in mice, rats or
guinea pigs at study termination. No exposure-related neoplasms were identified.

3.7. Summary

Clinical signs noted in the acute and repeated-dose animal studies suggest that CS is highly
irritating. The majority of the acute inhalation exposure data in animals focused primarily on
lethality as an endpoint, and death was generally caused by pulmonary edema and congestion.
Kidney damage was also occasionally noted, but may have been secondary to anoxia. Genetic
toxicology results were mixed. The responses in the Salmonella gene mutation test were
generally negative, as were results of in vivo genotoxicity assays. CS induced trifluorothymidine
resistance in mouse L5178/TK lymphoma cells in the absence of S9, and induced both SCEs and
chromosomal aberrations in CHO cells in the presence and absence of S9. No developmental
toxicity was noted in rats or rabbits, and there was no evidence of carcinogenicity in rats or mice.

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4. SPECIAL CONSIDERATIONS
4.1. Metabolism and Disposition

Absorption

One cat with a cannulated trachea was exposed to CS aerosol by an oral-nasal mask to assess
absorption of CS by the upper respiratory tract (cannulation prevented access to the lower
respiratory tract), while a second cat was exposed via a tracheal tube to assess absorption by the
lower respiratory tract (Leadbeater, 1973). Blood concentrations of CS and its metabolites
following exposure to the upper and lower respiratory tract were about 30% and 80%,
respectively, of those measured in intact cats.

Toxicokinetics

The half-lives of CS, 2-chlorobenzylmalonitrile, and 2-chlorobenzaldehyde were measured in
vivo in cats after the chemicals were administered directly into the femoral artery via a cannula,
or in rabbits after CS was administered directly into the ear vein (Leadbeater, 1973; Paradowski,
1979). The half-lives in cats were 5.5, 9.5, and 4.5 seconds, respectively, regardless of whether
just CS or all of the individual chemicals were administered, and in rabbits ranged from 19-25,
38-55, and 38-41 seconds, respectively. The in vitro half-lives in blood of cats, humans and rats
were also measured: the half-lives of CS, 2-chlorobenzylmalonitrile, and 2-chlorobenzaldehyde
in cats were 5, 470, and 70 seconds, respectively; in humans were 5, 660, and 15 seconds,
respectively, and in rats were 7, 30, and 15 seconds, respectively (Leadbeater, 1973). The in
vitro half-life of CS in the blood of rabbits was higher at approximately 60 seconds; the authors
postulated the increase in the half-life compared to rats, cats, and humans could be due to the
much greater concentration tested in rabbits (Paradowski, 1979).

CS incubated with rat liver homogenate for 5 minutes (ethanol-buffer; pH 7.4; 37°C) resulted
in a 59% decrease in the initial amount of glutathione, with 26% of the depletion occurring
spontaneously (non-enzymatically) (Rietveld et al., 1986). Binding to glutathione in vivo was
confirmed by enhanced urinary thioether excretion in rats following i.p. administration of CS
(Rietveld et al., 1983; 1986). The thioether was identified as 2-chlorobenzylmercapturic acid.

Metabolism

Metabolism of CS appears to be qualitatively similar in species. In vivo, CS can be
hydrolyzed to 2-chlorobenzaldehyde or malononitrile, or can be reduced to 2-chlorobenzyl
malononitrile (see Figure 1.) (Paradowski, 1979; Leadbeater, 1973). The 2-chlorobenzaldehyde
can then be oxidized to 2-chlorobenzoic acid for subsequent glycine conjugation, or reduced to
2-chlorobenzyl alcohol for ultimate excretion as 2-chlorobenzyl acetyl cysteine or 2-
chlorobenzyl glucuronic acid. The malononitrile can break down to cyanide, ultimately being
excreted as thiocyanate. The reduction of CS to 2-chlorobenzyl malononitrile is a relatively
minor pathway; 2-chlorobenzyl malononitrile can be conjugated with glycine, or can be
hydrolyzed to 2-chlorophenyl 2-cyanoproprionate.

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2-chlorobenzoic acid ~ 2-chlorohippuric acid

2-chlorobenzaldehyde



malonitrile ~^ (cyanide) ~^ thiocyanate

N.

1-chlorophenyl acetyl glycine

2-chlorobenzyl alcohol

>r 2-chlorobenzyl acetyl cysteine

2-chlorobenzyl glucuronic acid

2-chlorobenzyl malononitrile

^ 2-chloro phenyl-2-cayano propionamide 2-chlorophenyl 2-cyanopropionate

Figure 1. Summary of predominant metabolic pathways of CS in rats as proposed by
Rietveld et al., 1983; Paradowski, 1979; Leadbeater, 1973.

Radiolabeled CS was administered to rats intravenously (i.v.) (0.08, 0.8, and 80 [j,mol/kg of
3H-ring labeled; 0.8 and 80 [j,mol/kg of 14C-cyanide labeled; or 0.8 and 80 [j,mol/kg of (14C=C)
side-chain labeled CS) or intragastrically (80, 106, and 159 [j,mol/kg of 14C-cyanide labeled CS)
(Brewster et al., 1987). The major urinary metabolites recovered in rats up to 96 hours after i.v.
or intragastric administration of CS were 2-chlorohippuric acid (49% of dose), 2-chlorobenzyl
glucuronic acid (10%), 2-chlorobenzyl cysteine (8%), and 2-chlorobenzoic acid (8%), and minor
metabolites included 2-chlorophenyl acetyl glycine (3%), 2-chlorobenzyl alcohol (1.6%), and 2-
chlorophenyl 2-cyano propionate (1.6) (see Figure 1). In another investigation, the concentration
of cyanide and thiocyanate in rat urine over a 24-hour period was measured in untreated rats, rats
administered CS by i.v., or in rats exposed by i.p. or intragastric administration to the CS
hydrolysis product malononitrile. Following CS and malononitrile administration, urinary
cyanide levels remained at or below baseline levels, while thiocyanate levels generally increased
as the CS or malononitrile dose increased. The percentage molar conversion to CS to
thiocyanate was 21.5% at an i.p. dose of 212 [j,mol/kg and 30% at an intragastric dose of 212
[j,mol/kg, while it was 60% or more with a malononitrile i.p. dose of 80 [j,mol/kg or intragastric
malononitrile dose of 212 [j,mol/kg.

Metabolism in rabbits is similar to that in rats. The predominant biotransformation pathway
in the blood of rabbits administered high doses of CS by i.v. (0.5LD50 to the LD50) was
hydrolysis of CS to 2-chlorobenzyaldehyde and malononitrile (-30-40%), with a minor pathway
of reduction to 2-chlorobenzyl malononitrile (10%) (Paradowski, 1979). The authors stated that
the remaining 50-60%> of the administered CS disappeared from the blood by other means; no
other explanation was provided. The liver is involved in the metabolism of CS as demonstrated
by an increase in the half-lives of CS and its metabolites in blood of rabbits when the liver was
excluded from the circulation. More of the CS was accounted for after dosing, with
approximately 75% of the CS hydrolyzed to 2-chlorobenzyaldehyde and 15% reduced to 2-
chlorobenzyl malononitrile. When the kidney was excluded from the circulation, no changes
were observed in CS or metabolites in the blood.

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Maximum blood levels of CS and its derivatives in cats were attained 30 minutes after
intragastric administration of 40 mg/kg of CS (Leadbeater, 1973). By 90 minutes post dosing,
blood levels of 2-chlorobenzylmalonitrile and 2-chlorobenzaldehyde were still elevated, while
CS levels had returned to zero. When anesthetized cats were exposed for 60 minutes via oral-
nasal masks to CS aerosol (75 or 750 mg/m3 of pyrotechnically generated CS aerosol, 750
mg/m3 of pure CS aerosol from molten CS, or 62.5 mg/m3 of CS aerosol generated from an
aqueous suspension of micronized CS in acetic acid using a Collison sprayer), the levels of CS
and 2-chlorobenzylmalonitrile rapidly reached steady values, while that of 2-chlorobenzaldehyde
continued to increase. The blood levels resulting from exposure to 750 verses 75 mg/m3
pyrotechnically generated CS did not result in a 10-fold decrease in the concentration of CS and
its metabolites 2-chlorobenzylmalonitrile and 2-chlorobenzaldehyde: concentrations were
reduced by 4.5, 7.7, and 5.9, respectively. Exposure of cats to 100 mg/m3 of CS for 5
minutes/day for 4 days preceding exposure to 75 or 750 mg/m3 of CS resulted in reduced blood
concentrations of CS and its derivatives.

Rats receiving a single oral dose of 50-500 mg/kg of CS had lower blood levels of CS and its
derivatives compared to cats (Leadbeater, 1973). CS was only detected in the blood of rats
receiving the highest dose of 500 mg/kg of CS. As in cats, blood concentrations of 2-
chlorobenzylmalonitrile and 2-chlorobenzaldehyde in rats did not increase in a dose-related
manner. Rats breathing CS aerosol at concentrations of 14-245 mg/m3 for five minutes had
measurable amounts of CS and 2-chlorobenzylmalonitrile in the blood immediately after
exposure, but 2-chlorobenzaldehyde was detected only in rats exposed to concentrations greater
than 100 mg/m3.

Available animal data suggest that CS should be absorbed by the human respiratory tract
following inhalation exposure, and that CS should proceed via a similar metabolic pathway.
However, humans are not able to tolerate as great an exposure as animals. Six healthy human
males inhaled 0.5 to 1.5 mg/m3 of CS over 90 minutes, and blood was drawn before and after
exposure to measure CS and its derivatives (Leadbeater, 1973). Two men left the chamber
within 20 minutes. CS and 2-chlorobenzaldehyde were not detected in the blood of any of the
volunteers, and only a trace of 2-chlorobenzylmalonitrile was detected in the blood of one man
who remained in the chamber for the entire exposure.

Distribution and Elimination

To evaluate the fate of CS in rats, radiolabeled CS was administered intravenously (3H-ring
labeled, 14C-cyanide labeled, or (14C=C) side-chain labeled) or intragastrically (14C-cyanide
labeled) and urine, feces, and C02 collected over 96 hours post dosing (Brewster et al., 1987).
The majority of the administered dose was recovered in the urine, with recovery ranging from
44.4 to 100%. Recovery in feces up to 96 hours post dosing ranged from 1.2 to 23.4%, and
recovery in CO2 was minimal at 0 to 2.1%. When comparing the recovery of the three different
radiolabels following i.v. administration, more radioactivity was recovered in the feces of the
rats administered the (14C=C) side-chain labeled CS (21 to 23%) compared to the other two
labels (4 to 8%).

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Male mice were administered 14CN-CS by i.v., and were killed at selected time intervals and
autoradiographed to evaluate distribution (Brewster et al., 1987). A significant amount of
radioactivity was present in the gastrointestinal tract at five minutes post dosing. At one hour,
significant amounts of radioactivity were present in the gastrointestinal tract, urinary bladder,
mouth, and esophagus, with lesser amounts in the blood, liver, and salivary glands. At 24 hours,
most of the residual radioactivity was present in the mouth, salivary glands, gastrointestinal tract,
or urinary bladder.

4.2. Mechanism of Toxicity

CS is an SN2 alkylating agent, and therefore reacts directly with nucleophilic compounds
(Cucinell et al., 1971). Consequently, sulfhydryl-containing enzymes and other biological
compounds are prime targets. Most notably, CS reacts rapidly with the disulfhydryl form of
lipoic acid, a coenzyme in the pyruvate decarboxylase pathway. In vitro, CS reacted readily
with cysteine, N-acetyl L-cysteine, glutathione, dithiothreitol, and lipoic acid, with first order
reaction constants of 0.33, 0.42, 0.85, 4.88, and 10.4, respectively. CS incubated with rat liver
homogenate for 5 minutes (ethanol-buffer; pH 7.4; 37°C) resulted in a 59% decrease in the initial
amount of glutathione, with 26% of the depletion occurring spontaneously (non-enzymatically)
(Rietveld et al., 1986). Binding to glutathione in vivo was confirmed by enhanced urinary
thioether excretion in rats following i.p. administration of CS; the thioether was identified as 2-
chlorobenzylmercapturic acid (Rietveld et al., 1983; 1986). In another study, rats administered a
dose 120% of the LD50 by i.p. injection became moribund (most likely due to the relatively slow
generation of cyanide from the malononitrile metabolite) approximately 30 minutes after
injection. Support for the role of cyanide in the CS-induced lethality was the observation that
administration of thiosulfate intraveneously at this time reduced mortality by 65% compared to
control rats (21 of 32 rats survived compared to 1 of 11 control rats). Intravenous administration
of 8 mg/kg of CS in dogs resulted in a rapid drop in the plasma sulfhydryl concentration,
returning to normal within approximately 3 hours (Cucinell et al., 1971).

4.3. Other Relevant Information
4.3.1. Species Variability

CS is a potent acute irritant and the mode of ocular and pulmonary toxicity is direct contact
and its associated alkylating properties; therefore, the mechanism of action is not expected to
vary greatly among species. Ballantyne and Swantson (1978) calculated LCT50 values of 88,480
mg min/m3 for rats; 67,200 mg min/m3 for guinea pigs; 54,090 mg min/m3 for rabbits; and 50,010
mg min/m3 for mice, values all well within a factor of two.

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4.3.2. Susceptible Populations

CS is an irritant and the mechanism of toxicity is a direct contact effect; therefore, the
mechanism of action is not expected to vary greatly between individuals. The reactions of
volunteers with jaundice, hepatitis, or peptic ulcer or those that were 50-60 years old were
similar to those of "normal" volunteers when exposed to highly irritating concentration of CS for
short durations (Punte et al., 1963; Gutentag et al., 1960). Subjects with a history of drug
allergies or sensitivities, hay fever, or asthma also tolerated exposure to CS and were similar to
the "normal" subjects, but this group had a higher percentage of individuals with more severe
chest symptoms, many of them laying prostrate on the ground for several minutes. However, no
wheezing or rhonchi were heard, and recovery was as rapid as that seen in other exposure
groups.

4.3.3. Concentration-Exposure Duration Relationship

The concentration-exposure time relationship for many irritant and systemically-acting
vapors and gases can be described by the relationship cn x t = k, where the exponent, n, ranges
from 0.8 to 3.5 (ten Berge et al., 1986). An analysis of the available rat, mouse, rabbit, guinea
pig, dog, or monkey acute inhalation lethality data for derivation of the exponent 'n' was
conducted using using the DoseResp software of ten Berge (2006). These analyses utilized the
concentration-specific data contained in Tables 7, 9, 10 and 11, and produced the following
exponent 'n' values and confidence limits:

Rat:	0.704 (0.543-0.865)

Mouse:	0.701 (0.509-0.892)

Rabbit:	0.658 (0.467-0.849)

Guinea pig:	0.559(0.018-1.099)

Dog:	0.356 (-1.464-0.751)

Monkey:	0.187 (-0.281-0.656)

Details of the analysis are given in Appendix B.

5. DATA ANALYSIS FOR AEGL-1

5.1.	Summary of Human Data Relevant to AEGL-1

Several studies describe irritation in humans (Table 6); however, the severity of effects is
above the definition of AEGL-1.

5.2.	Summary of Animal Data Relevant to AEGL-1

No animal studies were available for development of AEGL-1 values.

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5.3. Derivation of AEGL-1

The AEGL-1 values will be based on human exposure to 1.5 mg/m3 for 90 minutes (Punte et
al., 1963). All four subjects could tolerate the exposure, but experienced eye and nose irritation
and headache. One subject developed nasal irritation within 2 minutes, three subjects developed
headache (at 45, 50, and 83 minutes), and all four experienced ocular irritation (at 20, 24, 70, and
75 minutes). Because the observed effects are above those defined by AEGL-1, a modifying
factor of 10 will be applied to reduce the point-of-departure from a LOAEL to a NOAEL for
AEGL-1 effects. An intraspecies uncertainty factor of 3 will be applied because contact
irritation is a portal-of-entry effect and is not expected to vary widely among individuals. The
intraspecies UF of 3 is also supported by the fact that responses of volunteers with jaundice,
hepatitis, or peptic ulcer or those that were 50-60 years old were similar to those of "normal"
volunteers when exposed to a highly irritating concentration of CS for short durations (Punte et
al., 1963; Gutentag et al., 1960). An interspecies uncertainty factor of 1 will be applied because
the study was conducted in humans. Time scaling was not applied in the development of the
AEGL-1 values, because the critical effect (irritation) is a function of direct contact with the tear
gas and is not likely to increase with duration of exposure at this level of severity (NRC, 2001).
AEGL-1 values are presented in Table 12.

TABLE 12. AEGL-1 Values for Tear Gas

10-min

30-min

1-h

4-h

8-hour

0.050 mg/m3

6. DATA ANALYSIS FOR AEGL-2

6.1. Summary of Human Data Relevant to AEGL-2

Four subjects exposed to 1.5 mg/m3 tolerated a 90 minute exposure, but experienced clinical
signs of irritation. One subject developed nasal irritation within 2 minutes, three subjects
developed headache (at 45, 50, and 83 minutes), and all four experienced ocular irritation (at 20,
24, 70, and 75 minutes) (Punte et al., 1963). When a total of 35 subjects were exposed for 60
minutes to CS concentrations ranging from 0.31-2.3 mg/m3, one subject left at 5 minutes due to
vomiting but returned for the duration of the exposure, another vomited at 55 minutes of
exposure (vomiting in both cases was ascribed to swallowing large amounts or saliva), and one
subject voluntarily left the exposure at 8 minutes due to irritation (Beswick et al., 1972).

Clinical signs noted during the 60-minute exposure included eye, nose, mouth, and throat
irritation, nausea, chest discomfort, headache, and stinging of the face.

6.2. Summary of Animal Data Relevant to AEGL-2

Blinking, mild pulmonary congestion, and emphysema were noted in monkeys exposed to
900 mg/m3 for 3 minutes or 1700 mg/m3 for 5 minutes. Monkeys exposed to 2500 mg/m3 for 32
minutes showed blinking labored respiration, coughing, oral and nasal discharge, vomiting,
decreased activity, pulmonary edema, and congestion (Striker et al., 1967). Mice exposed to 40

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mg/m3 for 5 hours had rhinorrhea and lacrimation, and guinea pigs exposed to 45 mg/m3 for 5
hours showed occasional sneezing during the first hour of exposure.

6.3. Derivation of AEGL-2

The AEGL-2 will be based on human exposure to 1.5 mg/m3 for 90 minutes (Punte et al.,
1963). All four subjects could tolerate the exposure, but experienced eye and nose irritation and
headache. An intraspecies uncertainty factor of 3 is applied because contact irritation is a portal-
of-entry effect and is not expected to vary widely among individuals. The intraspecies UF of 3 is
also supported by the fact that responses of volunteers with jaundice, hepatitis, or peptic ulcer or
those that were 50-60 years old were similar to those of "normal" volunteers when exposed to a
highly irritating concentration of CS for short durations (Punte et al., 1963; Gutentag et al.,
1960). An interspecies uncertainty factor of 1 is applied because the study was conducted in
humans. Time scaling is not applied in the development of the AEGL-2 values. The critical
effect (irritation) is a function of direct contact with the tear gas and is not likely to increase with
duration of exposure at this level of severity (NRC, 2001). AEGL-2 values are summarized in
Table 13 and calculations are in Appendix A.

TABLE 13. AEGL-2 Values for Tear Gas

10-min

30-min

1-h

4-h

8-h

0.50 mg/m3

These values are supported by the data of Beswick et al. (1972). When a total of 35
subjects were exposed for 60 minutes to CS concentrations ranging from 0.31-2.3 mg/m3, one
subject left at 5 minutes due to vomiting but returned for the duration of the exposure, and
another vomited at 55 minutes of exposure (vomiting in both cases ascribed to swallowing large
amounts or saliva). One subject voluntarily left the exposure at 8 minutes due to irritation; this
subject was exposed in the range of 0.56-0.86 mg/m3, and the AEGL-2 values are below this
exposure range. Although clinical signs of irritation were noted, five subjects exposed to a
constant 0.78 mg/m3 CS for 60 minutes all remained in the chamber for the entire exposure.
Again, the AEGL-2 values are below this exposure concentration.

7. DATA ANALYSIS FOR AEGL-3

7.1. Summary of Human Data Relevant to AEGL-3

No human studies were available for development of AEGL-3 values.

7.2. Summary of Animal Data Relevant to AEGL-3

Animal lethality data are available for rats, mice, rabbits, guinea pigs, dogs, and monkeys
exposed to varying concentrations of tear gas for varying time periods (McNamara et al., 1969;
Ballantyne and Calloway, 1972; Ballantyne and Swantson, 1978). Exposure durations ranged
from 5 to 300 minutes and concentrations ranged from 37 to 5176 mg/m3. Mortality incidences
ranged from 0 to 100%, depending on concentration-duration pairings. The experimental
parameters are summarized in Tables 7, 9, 10, and 11.

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7.3. Derivation of AEGL-3

Using the rat, mouse, rabbit, guinea pig, dog, and monkey data sets of McNamara et al..
(1969); Ballantyne and Calloway (1972); and Ballantyne and Swantson (1978) presented in
Tables 7, 9, 10, and 11, the threshold for lethality at each AEGL-3 exposure duration was
calculated using the probit-analysis based dose-response program of ten Berge (2006) (Appendix
B). The threshold for lethality was set at the LCoi. The rat, mouse, and rabbit data all yielded
similar time-scaling 'n' values and AEGL-3 values (Appendix B). Large variances in dog and
monkey data precluded calculation of 95% confidence intervals. The rat data set was chosen for
derivation of AEGL-3 values because it yielded values most consistent with the available human
data. The rat data indicated a time-scaling value of 0.704 (C0 704x t = k). The 4-hour AEGL-3
value was adopted as the 8-hour AEGL-3 value because time scaling yielded an 8-hour value
inconsistent with the AEGL-2 values that were derived from a rather robust human data set.

This is likely a result of the methodology (time-scaling to 8-hrs with an exponent 'n' of 0.704).

Inter- and intraspecies uncertainty factors of 3 each are applied (total 10) and are considered
sufficient because clinical signs are likely caused by a direct chemical effect on the tissues. This
type of portal-of-entry effect is not likely to vary greatly between species or among individuals.
The interspecies UF of 3 is supported by calculated LCT50 values of 88,480 mg min/m3 for rats;
67,200 mg min/m3 for guinea pigs; 54,090 mg min/m3 for rabbits; and 50,010 mg min/m3 for
mice (Ballantyne and Swantson, 1978), values all well within a factor of two. The intraspecies
UF of 3 is supported by the fact that responses of volunteers with jaundice, hepatitis, or peptic
ulcer or those that were 50-60 years old were similar to those of "normal" volunteers when
exposed to highly irritating concentration of CS for short durations (Punte et al., 1963; Gutentag
et al., 1960). AEGL-3 values are summarized in Table 14 and calculations are in Appendix A.

TABLE 14. AEGL-3 Values for Tear Gas

10-min

30-min

1-h

4-h

8-h

140 mg/m3

29 mg/m3

11 mg/m3

1.5 mg/m3

1.5 mg/m3

The AEGL-3 values are considered protective. No mortality was noted in rats exposed to
1802 mg/m3 for 10-min (Ballantyne and Swantson, 1978), in rabbits at 1434 mg/m3 for 10 min
(Ballantyne and Swantson, 1978), or in mice and rabbits at 4250 mg/m3 for 10-min (Ballantyne
and Calloway, 1972). Dividing these concentrations by a total UF of 10, yields values ranging
from 140-425 mg/m3, suggesting that the derived 10-min AEGL-3 is appropriate. No mortality
was noted in guinea pigs exposed to 44.7 mg/m3 for 5-hr or mice exposed to 40 mg/m3 for 5-hr
(Ballantyne and Calloway, 1972). Applying a total UF of 10 to these concentrations, yields a
value of approximately 4.0 mg/m3 for 5-hours. One of ten rats died when exposed to 37 mg/m3
for 5-hr Ballantyne and Calloway, 1972). Dividing 37 mg/m3 by 2 to obtain an approximate
threshold for lethality, yields 18.5 mg/m3; application of a total UF of 10, yields a value of 1.9
mg/m3 for 5-hr. The values derived from the 5-hr data show that the AEGL-3 values are
protective.

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1

2	8. SUMMARY OF AEGLs

3	8.1. AEGL Values and Toxicity Endpoints

4

5	AEGL-land AEGL-2 values are based on irritation in humans, and AEGL-3 values are

6	based on an estimated threshold for lethality in rats. AEGL values for tear gas are summarized

7	in Table 15.

8

TABLE 15. Summary of AEGL Values

Classification

Exposure Duration

10-min

30-min

1-h

4-h

8-h

AEGL-1
(Nondisabling)

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

AEGL-2
(Disabling)

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

AEGL-3
(Lethal)

140 mg/m3

29 mg/m3

11 mg/m3

1.5 mg/m3

1.5 mg/m3

9

10

11

12	8.2. Comparison with Other Standards and Guidelines

13

14	Extant standards and guidelines for tear gas are presented in Table 16.

15

TABLE 16. Standards and Guidelines for Tear Gas

Guideline

Exposure Duration

10-min

30-min

1-h

4-h

8-h

AEGL-1

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

0.050 mg/m3

AEGL-2

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

0.50 mg/m3

AEGL-3

140 mg/m3

29 mg/m3

11 mg/m3

1.5 mg/m3

1.5 mg/m3













ERPG-1 (AIHA)a





0.005 mg/m3





ERPG-2 (AIHA)a





0.1 mg/m3





ERPG-3 (AIHA)a





25 mg/m3





IDLH (NIOSH)b



2 mg/m3







REL-TWA (NIOSH)0









0.4 mg/m3

PEL-TWA (OSHA)d









0.4 mg/m3

TLV-STEL (ACGIH)e

0.005 ppm (0.4 mg/m3)







MAC

(The Netherlands/









0.4 mg/m3

16

17	aERPG (Emergency Response Planning Guidelines, American Industrial Hygiene Association (AIHA 2008)

18	The ERPG-1 is the maximum airborne concentration below which it is believed nearly all individuals could be

19	exposed for up to one hour without experiencing other than mild, transient adverse health effects or without

20	perceiving a clearly defined objectionable odor. The ERPG-1 for tear gas is based on one of ten individuals

21	reporting a burning or itching sensation at 0.0004 mg/m3 and a calculated EC50 of 0.004 mg/m3.

22

23	The ERPG-2 is the maximum airborne concentration below which it is believed nearly all individuals could be

24	exposed for up to one hour without experiencing or developing irreversible or other serious health effects or

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symptoms that could impair an individual's ability to take protection action. The ERPG-2 for tear gas is based
on human irritation data.

The ERPG-3 is the maximum airborne concentration below which it is believed nearly all individuals could be
exposed for up to one hour without experiencing or developing life-threatening health effects. The ERPG-3 for
tear gas is based on animal lethality data (approximate one-hr LC50).

immediately Dangerous to Life and Health (IDLH) is defined by the NIOSH/OSHA Standard Completions Program
only for the purpose of respirator selection and represents a maximum concentration from which, in the event of
respiratory failure, one could escape within 30 minutes without experiencing any escape-impairing or irreversible
health effects (NIOSH, 2005). (Basis: Acute inhalation toxicity in humans, Punte et al., 1963).

°NIOSH REL-TWA (National Institute of Occupational Safety and Health, Recommended Exposure Limits - Time
Weighted Average) (NIOSH 2005) is defined analogous to the ACGIH-TLV-TWA.

dOSHA PEL-TWA (Occupational Health and Safety Administration, Permissible Exposure Limits - Time Weighted
Average) (OSHA 1996) is defined analogous to the ACGIH-TLV-TWA, but is for exposures of no more than 10
hours/day, 40 hours/week.

e ACGIH TLV-STEL (American Conference of Governmental Industrial Hygienists, Threshold Limit Value -
Short Term Exposure Limit) (ACGIH 2008) is for a 15-minute exposure, ceiling.

fMAC (Maximaal Aanvaarde Concentratie [Maximal Accepted Concentration]). SDU Uitgevers (under the auspices
of the Ministry of Social Affairs and Employment), The Hague, The Netherlands 2000, is defined analogous to the
ACGIH-TLV-TWA.

9. REFERENCES

ACGIH (American Conference of Government and Industrial Hygienists). 1991.
Documentation of the Threshold Limit Values and Biological Exposure Indices: o-
Chlorobenzylidene malononitrile. Sixth ed., ACGIH, Cincinnati, OH.

ACGIH (American Conference of Government and Industrial Hygienists). 2008. TLVs and
BEIs Based on the Documentation of the Threshold Limit Values for Chemical Substances and
Physical Agents and Biological Exposure Indices: o-Chlorobenzylidene malononitrile. ACGIH,
Cincinnati, OH.

AIHA (American Industrial Hygiene Association). 2008. Emergency Response Planning
Guidelines for o-chlorobenzylidene malononitrile. AIHA, Fairfax, VA.

Anderson, P.J., Lau, G.S., Taylor, W.R., Critchley, J.A. 1996. Acute effects of the potent
lacrimator o-chlorobenzylidene malononitrile (CS) tear gas. Hum. Exp. Toxicol. 15: 461-465.

Ballantyne, B. 1977. Riot control agents. In: Medical Annual. Eds.: R.B. Scott and J. Fraser.
John Wright & Sons, Ltd., Bristol, Great Britain, pp. 7-41.

Ballantyne, B., Beswick, F.W. 1972. On the possible relationship between diarrhea and o-
chlorobenzylidene malononitrile (CS). Med. Sci. Law. 12: 121-128.

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Ballantyne, B., Callaway, S. 1972. Inhalation toxicology and pathology of animals exposed to
o-chlorobenzylidene malononitrile. Med. Sci. Law 12: 43-65.

Ballantyne, B., Swanston, D.W. 1978. The comparative acute mammalian toxicity of 1-
chloroacetophenone (CN) and 2-chlorobenzylidene malononitrile (CS). Arch Toxicol; 40: 75-
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Bauchinger, M., Schmid, E. 1992. Clastogenicity of 2-chlorobenzylidene malonitrile (CS) in
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Beswick, F.W., Holland, P., Kemp, K.H. 1972. Acute effects of exposure to
orthochlorobenzilidene malononitrile (CS) and the development of tolerance. Br. J. Indust. Med.
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Blain, P.G. 2003. Tear gases and irritant incapacitants. 1-chloroacetophenone, 2-
chlorobenzylidene malononitrile and dibenz[b,f]-l,4-oxazepine. Toxicol. Rev. 22: 103-210.

Breakell, A., Bodiwal, G.G. 1998. CS gas exposure in a crowded night club: the consequences
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Cole, T.J., Cotes, J.E., Johnson, G.R., de V. Martin, H., Reed, J.W., Saunders, M.J. 1975.
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Cole, T.J., Cotes, J.E., Johnson, G.R., de V. Martin, H., Reed, J.W., Saunders, M.J. 1977.
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Col grave, H.F., Creasey, J.M. 1975. Ultrastructure of rat lungs following exposure to o-
chlorobenzylidene malononitrile (CS). Med. Sci. Law. 15:187-197.

Corson, B.B., Stoughton, R.W. 1928. Reaction of a,P-unsaturated dinitriles. J. Am. Chem. Soc.
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Cotes, J.E., Evans, L.R., Johnson, GR, de V. Martin, H., Reed, J.W. 1972. The effect of CS
aerosol upon exercise ventilation and cardiac frequency in healthy men. J. Physiol. 222: 77P-
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Craig, F.N., Blevin, W.V., Cummings, E.G. 1960. Breathing patterns during human exposure to
CS. US Army Chemical Corps Research and Develop Command, Report No. CWLR 2399, June
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Cucinell, S.A., Swentzel, K.C., Biskup, R., Snodgrass, H., Lovre, S., Stark, W., Feinsilver, L.,
and Vocci, R. 1971. Biochemical interactions and metabolic fate of riot-control agents. Fed.
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Daniken, A., Friederich, U., Lutz, W.K., Schlatter, C. 1981. Tests for mutagenicity in
Salmonella and covalent binding to DNA and protein in the rat of the riot control agent o-
chlorobenzylidene malononitrile (CS). Arch. Toxicol. 49:15-27.

Euripidou, E., MacLehose, R., Fletcher, A. 2004. An investigation into the short term and
medium term health impacts of personal incapacitant sprays. A follow up of patients reported to
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Gaskins, J.R., Hehir, R.M., McCaulley, D.F., Ligon, E.W. 1972. Lacrimating agents (CS and
CN) in rats and rabbits: Acute effects on mouth, eyes, and skin. Arch. Environ. Health. 24: 449-
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Gray, P.J. 2000. Is CS spray dangerous? Formulation affects toxicity. B.M.J. 321:46-47.

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control agent in man. Technical Report CWLR 2365, April 1960, U.S. Army Chemical Warfare
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APPENDIX A: Derivation of Tear Gas AEGLs
Derivation of AEGL-1 Values

Key Study:	Punte et al., 1963

Toxicity endpoint:

Human exposure to 1.5 mg/m3 for 90 minutes. All four subjects could tolerate the exposure, but
experienced eye and nose irritation and headache.

Time scaling:

Not applied. The critical effect (irritation) is a function of direct contact with the tear gas and is not likely
to increase with duration of exposure at this level of severity (NRC, 2001).

Uncertainty factors:	Total uncertainty factor: 3

Interspecies: 1, human data

Intraspecies: 3, contact irritation is a portal of entry effect and is not expected
to vary widely between individuals. The intraspecies UF of 3 is also
supported by the fact that responses of volunteers with jaundice, hepatitis, or
peptic ulcer or those that were 50-60 years old were similar to those of
"normal" volunteers when exposed to a highly irritating concentration of CS
for short durations (Punte et al., 1963; Gutentag et al., 1960).

Modifying factor:	10: Reduction of point-of-departure from LOAEL to NOAEL for AEGL-1

effects

Calculations:

10-minute, 30-minute, 1-hour, 4-hour and 8-hour AEGL-1:
1.5 mg/m3 10 3 = 0.050 mg/m3

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Derivation of AEGL-2 Values

Key Study:	Punte et al., 1963

Toxicity endpoint:

Human exposure to 1.5 mg/m3 for 90 minutes. All four subjects could tolerate the exposure, but
experienced eye and nose irritation and headache.

Time scaling:

Not applied. The critical effect (irritation) is a function of direct contact with the tear gas and is not likely
to increase with duration of exposure at this level of severity (NRC, 2001).

Uncertainty factors:	Total uncertainty factor: 3

Interspecies: 1, human data

Intraspecies: 3, contact irritation is a portal of entry effect and is not expected
to vary widely between individuals. The intraspecies UF of 3 is also
supported by the fact that responses of volunteers with jaundice, hepatitis, or
peptic ulcer or those that were 50-60 years old were similar to those of
"normal" volunteers when exposed to a highly irritating concentration of CS
for short durations (Punte et al., 1963; Gutentag et al., 1960).

Modifying factor:	None applied

Calculations:

10-minute, 30-minute, 1-hour, 4-hour and 8-hour AEGL-2:
1.5 mg/m3 3 = 0.50 mg/m3

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Derivation of AEGL-3 Values

Key Studies: McNamara et al.. (1969); Ballantyne & Calloway (1972); Ballantyne & Swantson (1978)

Toxicity endpoint:	Threshold for lethality in rats (L0i) calculated using probit-analysis dose-

response program of ten Berge (2006).

Time scaling: Cn x t = k where n = 0.704 based on rat lethality data. The 4-hour AEGL-3 value was
adopted as the 8-hour AEGL-3 value because time scaling yielded an 8-hour value inconsistent with the
AEGL-2 values that were derived from a rather robust human data set. This is likely a result of the
methodology (time-scaling to 8-hrs with an exponent 'n' of 0.704).

Uncertainty factors: Total uncertainty factor: 10

Interspecies: 3 - effects are likely caused by a direct chemical effect on the tissues. This type of
portal-of-entry effect is not likely to vary greatly between species. Supported by calculated LCT50 values of
88,480 mg min/m3 for rats; 67,200 mg min/m3 for guinea pigs; 54,090 mg min/m3 for rabbits; and 50,010 mg
min/m3 for mice (Ballantyne and Swantson, 1978), values all well within a factor of two.

Intraspecies: 3- effects are likely caused by a direct chemical effect on the tissues. This type of portal-of
entry effect is not likely to vary greatly among individuals. Supported by the fact that responses of
volunteers with jaundice, hepatitis, or peptic ulcer or those that were 50-60 years old were similar to those
of "normal" volunteers when exposed to highly irritating concentration of CS for short durations (Punte et
al., 1963; Gutentag etal., 1960).

Data for calculations

Concentration (mg/m3)

Exposure duration (min)

Mortality incidence

560

25

1/10

543

35

2/10

489

45

3/10

454

55

5/10

500

60

2/10

500

80

6/10

500

90

8/10

750

30

0/8

150

120

0/8

3950

5

0/10

4760

5

0/10

4250

10

1/10

4330

10

1/10

4150

15

0/10

5167

15

7/10

4000

20

9/10

4300

20

8/10

1802

10

0/20

1806

45

8/20

1911

45

9/20

2629

60

20/21

2699

60

20/20

37

300

1/10

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1

Program output

Exposure Duration

LCoi point estimate

AEGL-3 Value (UF = 10)

10 minutes

1385 mg/m3

140 mg/m3

30 minutes

291 mg/m3

29 mg/m3

1 hour

109 mg/m3

11 mg/m3

4 hours

15 mg/m3

1.5 mg/m3

8 hours

5.6 mg/m3

1.5 mg/m3*

2	n= 0.704 mg/m3

3

4	* The 4-hour AEGL-3 value was adopted as the 8-hour AEGL-3 value because time scaling yielded an 8-

5	hour value inconsistent with the AEGL-2 values that were derived from a rather robust human data set.

6	This is likely a result of the methodology (time-scaling to 8-hrs with an exponent 'n' of 0.704).

7

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APPENDIX B: Time Scaling Calculations

The relationship between dose and time for any given chemical is a function of the
physical and chemical properties of the substance and the unique toxicological and
pharmacological properties of the individual substance. Historically, the relationship according
to Haber (1924), commonly called Haber's Law or Haber's Rule (i.e., C x t = k, where C =
exposure concentration, t = exposure duration, and k= a constant) has been used to relate
exposure concentration and duration to effect (Rinehart and Hatch, 1964). This concept states
that exposure concentration and exposure duration may be reciprocally adjusted to maintain a
cumulative exposure constant (k) and that this cumulative exposure constant will always reflect a
specific quantitative and qualitative response. This inverse relationship of concentration and
time may be valid when the toxic response to a chemical is equally dependent upon the
concentration and the exposure duration. However, an assessment by ten Berge et al. (1986) of
LC50 data for certain chemicals revealed chemical-specific relationships between exposure
concentration and exposure duration that were often exponential. This relationship can be
expressed by the equation C" xt = k, where n represents a chemical specific, and even a toxic
endpoint specific, exponent. The relationship described by this equation is basically the form of a
linear regression analysis of the log-log transformation of a plot of C vs t. ten Berge et al. (1986)
examined the airborne concentration (C) and short-term exposure duration (t) relationship
relative to death for approximately 20 chemicals and found that the empirically derived value of
n ranged from 0.8 to 3.5 among this group of chemicals. Hence, the value of the exponent (//) in
the equation Cn xt = k quantitatively defines the relationship between exposure concentration
and exposure duration for a given chemical and for a specific health effect endpoint. Haber's
Rule is the special case where n= 1. As the value of n increases, the plot of concentration vs
time yields a progressive decrease in the slope of the curve.

An n of 0.704 mg/m3 for tear gas was obtained following analysis of lethality data in rats
(McNamara et al., 1969; Ballantyne & Calloway, 1972; Ballantyne & Swantson, 1978) using the
software of ten Berge. This exposure-time relationship for lethality was considered appropriate
for AEGL-3 development. The 4-hour AEGL-3 value was adopted as the 8-hour AEGL-3 value
because time scaling yielded an 8-hour value inconsistent with the AEGL-2 values that were
derived from a rather robust human data set. This is likely a result of the methodology (time-
scaling to 8-hrs with an exponent 'n' of 0.704).

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1

2

	3			Tear Gas ten Berge program results- lethality 1%

Species

Exponent'n'

LCqi Point Estimate

Reference(s)





10-min

30-min

1-hr

4-hr

8-hr



Rat

0.704 (0.543-0.865)

1385 (477-2500)

290 (97-496)

109 (32-196)

15 (3.1-35)

5.6 (-0.93-15)

McNamara et al., 1969
Ballantyne and Calloway, 1972
Ballantyne and Swantson, 1978

Mouse

0.701 (0.509-0.892)

998 (208-1899)

208 (36-404)

77 (11-166)

11 (-0.86-3.2)

4.0 (-0.23-15)

McNamara et al., 1969
Ballantyne and Calloway, 1972
Ballantyne and Swantson, 1978

Rabbit

0.658 (0.467-0.849)

656 (227-1136)

124 (28-249)

43 (7.0-103)

5.2 (0.40-19)

1.8 (0.094-8.6)

McNamara et al., 1969
Ballantyne and Calloway, 1972
Ballantyne and Swantson, 1978

Guinea pig

0.559 (0.018-1.099)

3.65 (0-100)

0.51 (0-25)

0.15 (0-12)

0.012 (0-3.3)

0.0036 (0-1.8)

McNamara et al., 1969
Ballantyne and Calloway, 1972
Ballantyne and Swantson, 1978

















Dog

0.356 (-1.464-0.751)

349*

7604*

53150*

2597000*

18150000*

McNamara et al., 1969

Monkey

0.187 (-0.281-0.656)

26*

0.075*

0.0018*

0.0000011*

0.000000028*

McNamara et al., 1969
Striker et al., 1967

Monkey

2.123 (-21-25)

11*

6.6*

4.7*

2.5*

1.8*

McNamara et al., 1969

4 *Large variances precluded estimating 95% confidence limits.

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Filename: Tear gas rat for Log Probit Model
Date: 02 October 2008 Time: 09:11:09

Seq.nr cone mg/m3 minutes exposed responded

1

560

25

10

1

2

543

35

10

2

3

489

45

10

3

4

454

55

10

5

5

500

60

10

2

6

500

80

10

6

7

500

90

10

8

8

750

30

8

0

9

150

120

8

0

10

3950

5

10

0

11

4760

5

10

0

12

4250

10

10

1

13

4330

10

10

1

14

4150

15

10

0

15

5176

15

10

7

16

4000

20

10

9

17

4300

20

10

8

18

1802

10

20

0

19

1806

45

20

8

20

1911

45

20

9

21

2629

60

21

20

22

2699

60

20

20

23

37

300

10

1

Used Probit Equation Y = B0 + B1*X1 + B2*X2
XI = cone mg/m3, ln-transformed
X2 = minutes, ln-transformed

ChiSquare = 50.11
Degrees of freedom = 20
Probability Model = 2.13E-04

Ln(Likelihood) = -47.54

B 0
B 1
B 2

= -9.6233E+00
= 1.1705E+00
= 1.6634E+00

Student t =
Student t =
Student t =

-3.9484
5.6748
5.6382

variance B 0 0 = 5.9402E+00
covarianceBO 1 =-4.8485E-01
covarianceBO 2 =-6.7032E-01
variance B 1 1 = 4.2542E-02

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covariance B 1 2 = 4.9302E-02
variance B 2 2 = 8.7045E-02

Estimation ratio between regression coefficients of ln(conc) and ln(minutes)
Point estimate = 0.704
Lower limit (95% CL) = 0.543
Upper limit (95% CL) = 0.865

Estimation of cone mg/m3 at response of 1 %
minutes =10

Point estimate concmg/m3 = 1.385E+03 for response of 1 %

Lower limit (95% CL) cone mg/m3 = 4.772E+02 for response of 1 %
Upper limit (95% CL) cone mg/m3 = 2.500E+03 for response of 1 %

Estimation of cone mg/m3 at response of 1 %
minutes =30

Point estimate concmg/m3 = 2.906E+02 for response of 1 %

Lower limit (95% CL) cone mg/m3 = 9.659E+01 for response of 1 %
Upper limit (95% CL) cone mg/m3 = 4.963E+02 for response of 1 %

Estimation of cone mg/m3 at response of 1 %
minutes = 60

Point estimate concmg/m3 = 1.085E+02 for response of 1 %

Lower limit (95% CL) cone mg/m3 = 3.223E+01 for response of 1 %
Upper limit (95% CL) cone mg/m3 = 1.958E+02 for response of 1 %

Estimation of cone mg/m3 at response of 1 %
minutes = 120

Point estimate concmg/m3 = 4.052E+01 for response of 1 %

Lower limit (95% CL) cone mg/m3 = 1.021E+01 for response of 1 %
Upper limit (95% CL) cone mg/m3 = 8.137E+01 for response of 1 %

Estimation of cone mg/m3 at response of 1 %
minutes = 240

Point estimate concmg/m3= 1.513E+01 for response of 1 %

Lower limit (95% CL) cone mg/m3 = 3.122E+00 for response of 1 %
Upper limit (95% CL) cone mg/m3 = 3.501E+01 for response of 1 %

Estimation of cone mg/m3 at response of 1 %
minutes = 480

Point estimate concmg/m3 = 5.649E+00 for response of 1 %

Lower limit (95% CL) cone mg/m3 = 9.345E-01 for response of 1 %
Upper limit (95% CL) cone mg/m3 = 1.540E+01 for response of 1 %

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APPENDIX C: Derivation Summary for Tear Gas

AEGL-l VALUES FOR TEAR GAS

10-min

30-min

1-h

4-h

8-hour

0.050 mg/m

0.050 mg/m

0.050 mg/m

0.050 mg/m

0.050 mg/m

Key Reference: Punte, C.L., Owens, E.J., Gutentag, P.J. 1963. Exposures to ortho-chlorobenzylidene

	malononitrile: Controlled human exposures. Arch Environ Health 6:72-80.	

Test Species/Strain/Number: Human/4	

Exposure Route/Concentration/Duration: Inhalation/1.5 mg/m3 for 90 minutes	

Effects:

Clinical signs of irritation. Exposure tolerated for full 90-minutes. One subject developed nasal irritation within
2 minutes, three subjects developed headache (at 45, 50, and 83 minutes), and all four experienced ocular

irritation (at 20, 24, 70, and 75 minutes).	

Endpoint/Concentration/Rationale: 90-minute exposure to 1.5 mg/m3 resulted in nasal and ocular irritation and

headache.	

Uncertainty Factors/Rationale:

Total uncertainty factor: 3
Interspecies: 1, human data.

Intraspecies: 3, contact irritation is a portal of entry effect and is not expected to vary widely between
individuals. Also supported by the fact that responses of volunteers with jaundice, hepatitis, or peptic
ulcer or those that were 50-60 years old were similar to those of "normal" volunteers when exposed to a

	highly irritating concentration of CS for short durations (Punte et al., 1963; Gutentag et al., 1960).	

Modifying Factor: 10- Reduction of point-of-departure from LOAEL to NOAEL for AEGL-l effects	

Animal to Human Dosimetric Adjustment: Not applicable	

Time Scaling: Not applied. The critical effect (irritation) is a function of direct contact with the tear gas and is

not likely to increase with duration of exposure at this level of severity (NRC, 2001).	

Data Adequacy: No data meeting the definition of AEGL-l were available, necessitating MF application to
estimate a NOAEL for AEGL-l effects.

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TEAR GAS (CS)

Interim: September 2009/ Page 62 of 68

AEGL-2 VALUES FOR TEAR GAS

10-minute

30-minute

1-hour

4-h

8-h

0.50 mg/m3

Key Reference: Punte, C.L., Owens, E.J., Gutentag, P.J. 1963. Exposures to ortho-chlorobenzylidene

malononitrile: Controlled human exposures. Arch Environ Health 6:72-80.

Test Species/Strain/Number: Human/4

Exposure Route/Concentration/Duration: Inhalation/1.5 mg/m3 for 90 minutes

Effects:

Clinical signs of irritation. Exposure tolerated for full 90-minutes. One subject developed nasal irritation within
2 minutes, three subjects developed headache (at 45, 50, and 83 minutes), and all four experienced ocular

irritation (at 20, 24, 70, and 75 minutes).

Endpoint/Concentration/Rationale: 90-minute exposure to 1.5 mg/m3 resulted in nasal and ocular irritation and

headache.

Uncertainty Factors/Rationale:

Total uncertainty factor: 3
Interspecies: 1, human data.

Intraspecies: 3, contact irritation is a portal of entry effect and is not expected to vary widely between
individuals. Also supported by the fact that responses of volunteers with jaundice, hepatitis, or peptic
ulcer or those that were 50-60 years old were similar to those of "normal" volunteers when exposed to a

highly irritating concentration of CS for short durations (Punte et al., 1963; Gutentag et al., 1960).

Modifying Factor: None applied

Animal to Human Dosimetric Adjustment: Not applicable

Time Scaling: Not applied. The critical effect (irritation) is a function of direct contact with the tear gas and is

not likely to increase with duration of exposure at this level of severity (NRC, 2001).

Data Adequacy: AEGL-2 values are supported by the data of Beswick et al. (1972). When a total of 35
subjects were exposed for 60 minutes to CS concentrations ranging from 0.31-2.3 mg/m3, one subject left at 5
minutes due to vomiting but returned for the duration of the exposure, and another vomited at 55 minutes of
exposure (vomiting in both cases ascribed to swallowing large amounts or saliva). One subject voluntarily left
the exposure at 8 minutes due to irritation; this subject was exposed in the range of 0.56-0.86 mg/m3, and the
AEGL-2 values are below this exposure range. Although clinical signs of irritation were noted, five subjects
exposed to a constant 0.78 mg/m3 CS for 60 minutes all remained in the chamber for the entire exposure. Again,
the AEGL-2 values are below this exposure concentration.

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TEAR GAS (CS)

Interim: September 2009/ Page 63 of 68

AEGL-3 VALUES FOR TEAR GAS

10-min

30-min

1-h

4-h

8-h

140 mg/m3

29 mg/m3

11 mg/m3

1.5 mg/m3

1.5 mg/m3

Key References: McNamara, B.P., Owens, E.J., Weimer, J.T., Ballard, T.A., Vocci, F.J. 1969. Toxicology of
riot control chemicals CS, CN, and DM. Edgewood Arsenal Technical Report, EATR-4309 (Nov. 1969), Dept
of the Army, Edgewood Arsenal Medical Research Laboratory, Edgewood Arsenal, MD.

Ballantyne, B., Callaway, S. 1972. Inhalation toxicology and pathology of animals exposed to o-
chlorobenzylidene malononitrile. Med. Sci. Law 12: 43-65.

Ballantyne, B., Swanston, D.W. 1978. The comparative acute mammalian toxicity of 1-chloroacetophenone
(CN) and 2-chlorobenzylidene malononitrile (CS). Arch Toxicol; 40: 75-95.

Test Species/Strain/Number: Rat/Various /8, 10, 20, or 21 per group

Exposure Route/Concentration/Duration: Inhalation/Rats exposed to varying concentrations of tear gas for
varying durations. Exposure durations ranged from 5 to 300 minutes and concentrations ranged from 37 to 5176
mg/m3.	

Effects: Mortality: Concentrations, durations, incidence as in Appendix A: Derivation of AEGL-3 values.

Endpoint/Concentration/Rationale: Threshold for lethality in rats (LC01) calculated using probit-analysis dose-
response program of ten Berge (2006).	

Uncertainty Factors/Rationale:

Total uncertainty factor: 10

Interspecies: 3, effects are likely caused by a direct chemical effect on the tissues. This type of portal-of-
entry effect is not likely to vary greatly between species. Supported by calculated LCT50 values of 88,480 mg min/m
for rats; 67,200 mg min/m3 for guinea pigs; 54,090 mg min/m3 for rabbits; and 50,010 mg min/m3 for mice
(Ballantyne and Swantson, 1978), values all well within a factor of two.

Intraspecies: 3, effects are likely caused by a direct chemical effect on the tissues. This type of portal-of entry
effect is not likely to vary greatly among individuals. Supported by the fact that responses of volunteers with
jaundice, hepatitis, or peptic ulcer or those that were 50-60 years old were similar to those of "normal" volunteers
A lien exposed to highly irritating concentration of CS for short durations (Punte et al., 1963; Gutentag et al., 1960).

Modifying Factor: None applied

Animal to Human Dosimetric Adjustment: Not applicable

Time Scaling: Cn x t = k, where n = 0.704 based on rat lethality data. The 4-hour AEGL-3 value was adopted as
the 8-hour AEGL-3 value because time scaling yielded an 8-hour value inconsistent with the AEGL-2 values that
were derived from a rather robust human data set. This is likely a result of the methodology (time-scaling to 8-
hrs with an exponent "n" of 0.704).	

Data Adequacy: The AEGL-3 values are considered protective. No mortality was noted in rats exposed to 1802
mg/m3 for 10-min (Ballantyne and Swantson, 1978), in rabbits at 1434 mg/m3 for 10 min (Ballantyne and
Swantson, 1978), or in mice and rabbits at 4250 mg/m3 for 10-min (Ballantyne and Calloway, 1972). Dividing
these concentrations by a total UF of 10, yields values ranging from 140-425 mg/m3, suggesting that the derived
10-min AEGL-3 is appropriate. No mortality was noted in guinea pigs exposed to 44.7 mg/m3 for 5-hr or mice
exposed to 40 mg/m3 for 5-hr (Ballantyne and Calloway, 1972). Applying a total UF of 10 to these
concentrations, yields a value of approximately 4.0 mg/m3 for 5-hours. One of ten rats died when exposed to 37
mg/m3 for 5-hr Ballantyne and Calloway, 1972). Dividing 37 mg/m3 by 2 to obtain an approximate threshold for
lethality, yields 18.5 mg/m3; application of a total UF of 10, yields a value of 1.9 mg/m3 for 5-hr. The values
derived from the 5-hr data show that the AEGL-3 values are protective.	

1

2

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TEAR GAS (CS)

Interim: September 2009/ Page 64 of 68

APPENDIX D: CATEGORY PLOT FOR TEAR GAS

10000.0

1000.0

100.0

CO

E
E

10.0

1.0

0.1

0.0

Chemical Toxicity
Tear Gas

r.

!-

























: \















P~

~

AEGL-3











E















a- |







AEGL-2







z















-





AEGL-1









60	120 180 240 300 360 420

Minutes

~

Human - No Effect

~

Human - Discomfort

Human - Disabling

o

Animal -

o

Animal - No Effect

Animal - Discomfort

.nimal - Disabling

Animal - Partially Lethal

Animal - Lethal

480

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TEAR GAS (CS)

Interim: September 2009/ Page 65 of 68

1

Source Species Sex	# mg/m3	Minutes

Exposures

NAC/AEGL-1 0.050	10

NAC/AEGL-1 0.050	30

NAC/AEGL-1 0.050	60

NAC/AEGL-1 0.050	240

NAC/AEGL-1 0.050	480

NAC/AEGL-2 0.5 0	10

NAC/AEGL-2 0.5 0	30

NAC/AEGL-2 0.5 0	60

NAC/AEGL-2 0.5 0	240

NAC/AEGL-2 0.5 0	480

NAC/AEGL-3 140	10

NAC/AEGL-3 29	30

NAC/AEGL-3 11	60

NAC/AEGL-3 1.5	240

NAC/AEGL-3 1.5	480

human	1 94	1

human	1 85	1

human	1 1.5	90

human	1 6.7	2

human	1 6	18

human	1 0.4	10

human	1 0.6	10

human	1 0.9	10

human	1 1	1

human	1 0.78	60

human	1 0.56	8

human	1 0.31	60

human	1 0.8	60

human	1 0.84	60

human	1 2.3	60

human	1 0.7	60

human	1 2	60

human	1 0.63	60

human	1 2.3	60

human	1 0.57	60

Category Comments

AEGL
AEGL
AEGL
AEGL
AEGL

AEGL
AEGL
AEGL
AEGL
AEGL

AEGL
AEGL
AEGL
AEGL
AEGL

2 Intolerable airway and ocular irritation (Owens and Punte, 1963)

2 Intolerable airway and ocular irritation (Owens and Punte, 1963)

1 nasal & ocular irritation, headache (Punte et al, 1963)

1 Intolerable irritation; escape possible (Punte et al, 1963)

1 Intolerable irritation; escape possible (Punte et al, 1963)

1 Intense eye irritation (Rengsdorf, 1969)

1 Intense eye irritation (Rengsdorf, 1969)

1 Intense eye irritation (Rengsdorf, 1969)

1 Intense eye irritation (Rengsdorf, 1969)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throati rritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

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TEAR GAS (CS)

Interim: September 2009/ Page 66 of 68

human
human

monkey
monkey
monkey

monkey

2.1
0.42

900
1700
2850

2500

60
60

3
5
10

32

1 eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

1	eye, nose, throat irritation, nausea, chest discomfort, headaces
(Beswick et al., 1972)

2	Pulmonary congestion, emphysema (Striker et al, 1967)

2 Pulmonary congestion, emphysema (Striker et al, 1967)

2 Pulmonary congestion, emphysema, ocular/respiratory irritation
(Striker et al, 1967)

pi Severe irritation,Pulmonary edema, emphysema, Mortality: 5/8
(Striker et al, 1967)

mouse

1 40

300

1

Rhinorrhea and lacrimation (Ballantyne anc

rat

1 37

300

Pi

Rhinorrhea and lacrimation; Mortality 1/10









(Ballantyne and Calloway, 1972)

GP

1 45

300

1

Sneezing (Ballantyne and Calloway, 1972)

rat

1 560

25

Pi

Mortality: 1/10 (McNamara et al

, 1969)

rat

1 543

35

Pi

Mortality: 2/10 (McNamara et al

, 1969)

rat

1 489

45

Pi

Mortality: 3/10 (McNamara et al

, 1969)

rat

1 454

55

Pi

Mortality: 5/10 (McNamara et al

, 1969)

rat

1 500

60

Pi

Mortality: 2/10 (McNamara et al

, 1969)

rat

1 500

80

Pi

Mortality: 6/10 (McNamara et al

, 1969)

rat

1 500

90

Pi

Mortality: 8/10 (McNamara et al

, 1969)

Mouse

1 1200

10

2

Mortality: 0/20 (McNamara et al

, 1969)

mouse

1 1100

20

Pi

Mortality: 7/20 (McNamara et al

, 1969)

mouse

1 900

30

Pi

Mortality: 2/20 (McNamara et al

, 1969)

mouse

1 800

40

Pi

Mortality: 5/20 (McNamara et al

, 1969)

mouse

1 740

50

Pi

Mortality: 5/20 (McNamara et al

, 1969)

mouse

1 683

60

Pi

Mortality: 14/20 (McNamara et al., 1969)

GP

1 400

5

Pi

Mortality: 1/10 (McNamara et al

, 1969)

GP

1 400

10

Pi

Mortality: 2/10 (McNamara et al

, 1969)

GP

1 400

15

Pi

Mortality: 4/10 (McNamara et al

, 1969)

GP

1 500

20

Pi

Mortality: 3/10 (McNamara et al

, 1969)

GP

1 400

25

Pi

Mortality: 7/10 (McNamara et al

, 1969)

GP

1 400

30

Pi

Mortality: 7/10 (McNamara et al

, 1969)

GP

1 425

40

Pi

Mortality: 8/10 (McNamara et al

, 1969)

Rabbit

1 500

30

Pi

Mortality: 1/4 (McNamara et al.,

1969)

Rabbit

1 250

40

2

Mortality: 0/4 (McNamara et al.,

1969)

Rabbit

1 267

45

2

Mortality: 0/4 (McNamara et al.,

1969)

Rabbit

1 250

80

Pi

Mortality: 3/4 (McNamara et al.,

1969)

Rabbit

1 333

90

3

Mortality: 4/4 (McNamara et al.,

1969)

Dog

1 833

20

2

Mortality: o/4 (McNamara et al.,

1969)

Dog

1 649

30

Pi

Mortality: 1/4 (McNamara et al.,

1969)

Dog

1 508

36

Pi

Mortality: 2/4 (McNamara et al.,

1969)

Dog

1 899

40

Pi

Mortality: 2/4 (McNamara et al.,

1969)

Dog

1 520

45

Pi

Mortality: 2/4 (McNamara et al.,

1969)

Dog

1 612

45

Pi

Mortality: 2/4 (McNamara et al.,

1969)

Dog

1 797

60

Pi

Mortality: 3/4 (McNamara et al.,

1969)

Dog

1 909

60

Pi

Mortality: 2/4 (McNamara et al.,

1969)

Monkey

1 469

24

Pi

Mortality: 1/4 (McNamara et al.,

1969)

Monkey

1 673

30

Pi

Mortality: 2/4 (McNamara et al.,

1969)

Monkey

1 381

45

Pi

Mortality: 2/4 (McNamara et al.,

1969)

Monkey

1 612

45

Pi

Mortality: 1/4 (McNamara et al.,

1969)

Monkey

1 699

60

Pi

Mortality: 1/4 (McNamara et al.,

1969)

Monkey

1 941

60

Pi

Mortality: 3/4 (McNamara et al.,

1969)

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TEAR GAS (CS)

Interim: September 2009/ Page 67 of 68

Monkey



1057

60

Pi

Mortal

ty:

2/4 (McNamara etal., 1969)

Rat

m

750

30

2

Mortal

ty:

0/8 (Ballantyne and Calloway, 1972))

Rat



150

120

2

Mortal

ty:

0/8 (Ballantyne and Calloway, 1972))

Rat



3950

5

2

Mortal

ty:

0/10 (Ballantyne and Calloway, 1972)

Rat



4760

5

2

Mortal

ty:

0/10 (Ballantyne and Calloway, 1972)

Rat



4250

10

Pi

Mortal

ty:

1/10 (Ballantyne and Calloway, 1972)

Rat



4330

10

Pi

Mortal

ty:

1/10 (Ballantyne and Calloway, 1972)

Rat



4150

15

2

Mortal

ty

0/10 (Ballantyne and Calloway, 1972)

Rat



5167

15

Pi

Mortal

ty:

7/10 (Ballantyne and Calloway, 1972)

Rat



4000

20

Pi

Mortal

ty:

9/10 (Ballantyne and Calloway, 1972)

Rat



4300

20

Pi

Mortal

ty:

8/10 (Ballantyne and Calloway, 1972)

Mouse



3950

5

Pi

Mortal

ty:

1/10 (Ballantyne and Calloway, 1972)

Mouse



4760

5

2

Mortal

ty:

0/10 (Ballantyne and Calloway, 1972)

Mouse



4250

10

2

Mortal

ty:

0/10 (Ballantyne and Calloway, 1972)

Mouse



4330

10

Pi

Mortal

ty:

4/10 (Ballantyne and Calloway, 1972)

Mouse



4150

15

Pi

Mortal

ty:

3/10 (Ballantyne and Calloway, 1972)

Mouse



5167

15

Pi

Mortal

ty:

3/10 (Ballantyne and Calloway, 1972)

Mouse



4000

20

Pi

Mortal

ty:

8/10 (Ballantyne and Calloway, 1972)

Mouse



4300

20

Pi

Mortal

ty:

6/10 (Ballantyne and Calloway, 1972)

GP



3950

5

Pi

Mortal

ty:

1/5 (Ballantyne and Calloway, 1972)

GP



4760

5

2

Mortal

ty

0/5 (Ballantyne and Calloway, 1972)

GP



4250

10

3

Mortal

ty

5/5 (Ballantyne and Calloway, 1972)

GP



4330

10

Pi

Mortal

ty:

3/5 (Ballantyne and Calloway, 1972)

GP



4150

15

Pi

Mortal

ty:

3/5 (Ballantyne and Calloway, 1972)

GP



5167

15

3

Mortal

ty

5/5 (Ballantyne and Calloway, 1972)

GP



4000

20

3

Mortal

ty

5/5 (Ballantyne and Calloway, 1972)

GP



4300

20.00

3

Mortal

ty

5/5 (Ballantyne and Calloway, 1972)

Rabbit



3950

5

2

Mortal

ty:

0/5 (Ballantyne and Calloway, 1972)

Rabbit



4760

5

2

Mortal

ty:

0/5 (Ballantyne and Calloway, 1972)

Rabbit



4250

10

2

Mortal

ty:

0/5 (Ballantyne and Calloway, 1972)

Rabbit



4330

10

Pi

Mortal

ty:

2/5 (Ballantyne and Calloway, 1972)

Rabbit



4150

15

Pi

Mortal

ty:

2/5 (Ballantyne and Calloway, 1972)

Rabbit



5167

15

Pi

Mortal

ty:

2/5 (Ballantyne and Calloway, 1972)

Rabbit



4000

20

Pi

Mortal

ty:

4/5 (Ballantyne and Calloway, 1972)

Rabbit



4300

20

3

Mortal

ty:

5/5 (Ballantyne and Calloway, 1972)

Rat

m

1802

10

2

Mortal

ty:

0/20 (Ballantyne and Swantson, 1978)

Rat

m

1806

45

Pi

Mortal

ty:

8/20 (Ballantyne and Swantson, 1978)

Rat

m

1911

45

Pi

Mortal

ty:

9/20 (Ballantyne and Swantson, 1978)

Rat

m

2629

60

Pi

Mortal

ty:

20/21 (Ballantyne and Swantson, 1978)

Rat

m

2699

60

3

Mortal

ty:

20/20 (Ballantyne and Swantson, 1978)

Mouse

m

1432

15

Pi

Mortal

ty:

1/40 (Ballantyne and Swantson, 1978)

Mouse

m

2753

20

Pi

Mortal

ty:

17/40 (Ballantyne and Swantson, 1978)

Mouse

m

2333

30

Pi

Mortal

ty:

10/19 (Ballantyne and Swantson, 1978)

Mouse

m

2400

30

Pi

Mortal

ty:

17/40 (Ballantyne and Swantson, 1978)

Mouse

m

2550

30

Pi

Mortal

ty:

24/36 (Ballantyne and Swantson, 1978)

GP

f

2326

10

Pi

Mortal

ty:

2/20 (Ballantyne and Swantson, 1978)

GP

f

2380

15

Pi

Mortal

ty:

2/10 (Ballantyne and Swantson, 1978)

GP

f

1685

25

Pi

Mortal

ty:

10/20 (Ballantyne and Swantson, 1978)

GP

f

2310

20

Pi

Mortal

ty:

8/20 (Ballantyne and Swantson, 1978)

GP

f

1649

30

Pi

Mortal

ty:

11/20 (Ballantyne and Swantson, 1978)

GP

f

1302

45

Pi

Mortal

ty:

9/11 (Ballantyne and Swantson, 1978)

GP

f

2041

30

Pi

Mortal

ty:

13/20 (Ballantyne and Swantson, 1978)

-------
TEAR GAS (CS)	Interim: September 2009/ Page 68 of 68

GP f

1 2373

30

Pi

Mortal

ty:

10/19 (Ballantyne and Swantson, 1978)

Rabbit f

1 846

5

2

Mortal

ty:

0/10 (Ballantyne and Swantson, 1978)

Rabbit f

1 836

10

2

Mortal

ty:

0/10 (Ballantyne and Swantson, 1978)

Rabbit f

1 1434

10

2

Mortal

ty:

0/10 (Ballantyne and Swantson, 1978)

Rabbit f

1 1802

10

Pi

Mortal

ty:

1/5 (Ballantyne and Swantson, 1978)

Rabbit f

1 2188

15

Pi

Mortal

ty:

2/10 (Ballantyne and Swantson, 1978)

Rabbit f

1 2380

15

Pi

Mortal

ty:

3/8 (Ballantyne and Swantson, 1978)

Rabbit f

1 1407

30

Pi

Mortal

ty:

4/10 (Ballantyne and Swantson, 1978)

Rabbit f

1 1653

30

Pi

Mortal

ty:

2/10 (Ballantyne and Swantson, 1978)

Rabbit f

1 1309

45

Pi

Mortal

ty:

4/5 (Ballantyne and Swantson, 1978)

Rabbit f

1 2118

45

Pi

Mortal

ty:

9/10 (Ballantyne and Swantson, 1978)

Rabbit f

1 2133

60

Pi

Mortal

ty:

7/8 (Ballantyne and Swantson, 1978)

Rabbit f

1 3066

60

Pi

Mortal

ty:

8/9 (Ballantyne and Swantson, 1978)

-------