Association between exposure to o-chlorobenzylidene malononitrile (CS riot control agent) and urinary metabolite 2-chlorohippuric acid in U.S. Army Mask Confidence Training

This study was conducted among U.S. Army soldiers to evaluate the association between exposure to o-chlorobenzylidene malononitrile (CS riot control agent) and urinary metabolite 2-chlorohippuric acid (CHA) detected in test subjects (n = 87) after completion of Mask Confidence Training. CS exposures ranged 0.086-4.9 mg/m³ ([Formula: see text] = 2.7 mg/m³). CHA levels (corrected for creatinine) at 2-, 8-, 24-, and 30-hr post-exposure resulted in ranges of 94.6-1120 µg/g-cr ([Formula: see text] = 389 µg/g-cr), 15.80-1170 µg/g-cr ([Formula: see text] = 341 µg/g-cr), 4.00-53.1 µg/g-cr ([Formula: see text] = 19.3 µg/g-cr), and 1.99-28.4 µg/g-cr ([Formula: see text] = 10.6 µg/g-cr), respectively. Spearman's correlation revealed CHA levels strongly correlated with time sampled (r = -0.748, p < 0.05) and weakly correlated with CS concentration (r = 0.270, p < 0.05). A linear relationship was observed between CHA, CS concentration, and time of urine sample according to the following regression equation: ln(CHA, μg/g-cr) = 5.423 + 0.316 (CS conc., mg/m³) - 0.002 (time sampled), (R = 0.910, R² = 0.827, p < 0.05). This relationship suggests that CHA has the potential to be an effective retrospective indicator of CS exposure in future biomarker developments.

Can CS gas induce myocardial infarction?

"2-chlorobenzylidene malononitrile" also named CS gas is the most used riot-control agent in the world. Its reputation as the least toxic tear gas explains its large use by different authorities. Early exposure to CS spray commonly induces visual irritation, skin reactions, with increased mucous secretion in order to temporarily incapacitate targeted people. However, there is a large agreement that safety data of this product is limited and further studies need to be performed since serious problems could occur after heavy exposure such as loss of consciousness, laryngospasm, pulmonary edema and hemorrhage... Herein, we report a case of a young man who had acute myocardial infarction with serious cardiac sequelae after exposure to tear gas. To our knowledge, this is the second case since forty years in the literature that directly links documented acute heart infarction to CS gas exposure.

Can CS gas induce myocardial infarction?

"2-chlorobenzylidene malononitrile" also named CS gas is the most used riot-control agent in the world. Its reputation as the least toxic tear gas explains its large use by different authorities. Early exposure to CS spray commonly induces visual irritation, skin reactions, with increased mucous secretion in order to temporarily incapacitate targeted people. However, there is a large agreement that safety data of this product is limited and further studies need to be performed since serious problems could occur after heavy exposure such as loss of consciousness, laryngospasm, pulmonary edema and hemorrhage... Herein, we report a case of a young man who had acute myocardial infarction with serious cardiac sequelae after exposure to tear gas. To our knowledge, this is the second case since forty years in the literature that directly links documented acute heart infarction to CS gas exposure.

Secondary Contamination of Emergency Department Personnel from o-Chlorobenzylidene Malononitrile Exposure, 2002

In a hazardous materials event in 2002, the unannounced presentation of 3 symptomatic, contaminated patients to an emergency department (ED) resulted in secondary contamination of 2 ED personnel who experienced skin, eye, and respiratory irritation. The material that caused these injuries was o-chlorobenzylidene malononitrile, a white powder with a peppery odor used largely as a tear gas and riot-control agent. Secondary contamination can cause adverse symptoms and injuries in ED personnel, further contaminate the ED, and potentially lead to costly ED closures and evacuations. To prevent secondary exposure, EDs can educate their staff about the potential for secondary contamination, implement a team approach for handling contaminated patients, establish decontamination protocols, ensure proper selection of and training in the use of personal protective equipment, and simulate drills for receiving contaminated patients.

An investigation into the short term and medium term health impacts of personal incapacitant sprays. A follow up of patients reported to the National Poisons Information Service (London)

OBJECTIVES

The aim of this study is to describe the pattern of ill health after personal incapacitant spray (PIS) exposures reported to the National Poisons Information Service-London (NPIS-L) and the Chemical Incident Response Service and to evaluate the relation between sub-categories of PIS exposure and adverse health effects.

METHODS

Case series study of patients reported to the NPIS-L, by attending medical personnel during the period 16 January to 31 September 1998. Data collected by questionnaire sent to these medical personnel.

RESULTS

Several "adverse" symptoms, particularly dermatitis and blisters were reported for cases exposed to police PIS. These cases were more frequent than in those people exposed to non-police PIS. Adverse effects occurring more than six hours after exposure were also observed, which is in conflict with the recorded immediate, short lived, and self limiting symptoms that PIS are designed to cause. Most patients with persisting symptoms required further treatment.

CONCLUSIONS

These findings suggest that the formulation of CS (o-chlorobenzylidine malononitrile) with MiBK (methyl iso-butyl ketone) used by the police is more harmful that has been previously assumed. If confirmed then the continued use of this formulation should be reviewed because of longer duration of adverse effects. Less concentrated formulations may reduce the severity or persistence of the adverse effects.

Postoperative complications after CS spray exposure

Summary We report on airway complications associated with general anaesthesia in a subject who had been exposed to CS spray several hours before surgery. CS spray is a form of tear gas that is said to have a short half-life when the subject is removed from exposure. Induction of anaesthesia was uneventful. Marked laryngospasm occurred when the tracheal tube was removed at the end of the operation, and the anaesthetists experienced lacrimation and burning sensations typical of CS exposure. The effects on the attending anaesthetist made tracheal re-intubation difficult. There were no long-term adverse sequelae for the patient or anaesthetists. Suggestions are made for changes to anaesthetic practice and the advice given by the police about patients who have been exposed to CS spray.

[Medical aspects of the lacrimator CS]

Since the 1960's, CS has become the main riot control agent in use by police and army forces throughout the world. The first post-exposure symptom is a burning sensation in the eyes, nose and throat. At a later stage, lacrimation, rhinorrhea, conjunctivitis, sore throat and salivation appear. These symptoms are followed by chest pain and dry cough, and if the substance is swallowed, it may cause nausea and vomiting. This article reviews the physical properties of CS, the main dispersing techniques, the clinical signs and symptoms of exposure, including information on mutagenicity, carcinogenesis, pregnancy safety, and will introduce guidelines for treatment after exposure.

Tear Gases and Irritant Incapacitants

Irritant incapacitants, also called riot control agents, lacrimators and tear gases, are aerosol-dispersed chemicals that produce eye, nose, mouth, skin and respiratory tract irritation. Tear gas is the common name for substances that, in low concentrations, cause pain in the eyes, flow of tears and difficulty in keeping the eyes open. Only three agents are likely to be deployed: (i) 1-chloroacetophenone (CN); (ii) 2-chlorobenzylidene malononitrile (CS); or (iii) dibenz[b,f]-1,4-oxazepine (CR). CN is the most toxic lacrimator and at high concentrations has caused corneal epithelial damage and chemosis. It has accounted for at least five deaths, which have resulted from pulmonary injury and/or asphyxia. CS is a 10-times more potent lacrimator than CN but is less systemically toxic. CR is the most potent lacrimator with the least systemic toxicity and is highly stable. CN, CS and CR cause almost instant pain in the eyes, excessive flow of tears and closure of the eyelids, and incapacitation of exposed individuals. Apart from the effects on the eyes, these agents also cause irritation in the nose and mouth, throat and airways and sometimes to the skin, particularly in moist and warm areas. In situations of massive exposure, tear gas, which is swallowed, may cause vomiting. Serious systemic toxicity is rare and occurs most frequently with CN; it is most likely to occur when these agents are used in very high concentrations within confined non-ventilated spaces. Based on the available toxicological and medical evidence, CS and CR have a large safety margin for life-threatening or irreversible toxic effects. There is no evidence that a healthy individual will experience long-term health effects from open-air exposures to CS or CR, although contamination with CR is less easy to remove.

Effect of oleoresin capsicum (OC) and ortho-chlorobenzylidene malononitrile (CS) on ciliary beat frequency

Tear gases are largely used to control civil unrest. Their incapacitating effects involve the eyes, skin, and respiratory tract. We aimed to evaluate the effects of ortho-chlorobenzylidene malononitrile (CS) and oleoresin capsicum (OC) on ciliary beat frequency (CBF) of mouse tracheal rings. Addition of 0.05% OC or 0.01% CS induced a progressive decrease in CBF, from 11.5+/-0.5 to 4+/-0.1 Hz (P<0.05) and from 12.5+/-0.5 to 2.5+/-0.1 Hz (P<0.05), respectively, 30 min after exposure to the tear gas. Addition of exogenous ATP inhibited the effect of OC, suggesting that ATP could be used to counteract these adverse effects on CBF. However, ATP was inefficient against CS. Methylene blue and H7 inhibited the effects of OC, whereas indomethacin had no effect. None of these drugs affected the inhibitory action of CS. These results suggest that the inhibitory effect of OC is mediated through the guanylate cyclase-dependent pathway or protein kinase C-dependent phosphorylation. Another mechanism is probably involved in CS-induced inhibitory effect. Histological analysis of the trachea revealed an increase in mucus secretion after exposure to OC, and cytoplasmic vacuoles in epithelial cells after exposure to CS.

Comparative acute toxicity of o-chlorobenzylidene malononitrile (CS) and oleoresin capsicum (OC) in awake rats

Tear gases are largely used to control civil unrest. Their incapaciting effects involve eyes, skin and respiratory tract. This study was performed to compare acute respiratory effects of o-chlorobenzylidene malononitrile (CS), oleoresin capsicum (OC) and their respective solvents in awake rats, using an integrated system of nose-only exposure and multiple monitoring of breathing. Aerosols were generated by a Collison Nebulizer from the solutions held in tear gas sprays. The reduction of minute ventilation, observed during a 5 min exposure, was significantly more important with CS than with OC: minute ventilation represented 29+/-8 and 50+/-6% of pre-exposure minute ventilation respectively (P<0.05). The reduction of minute ventilation observed with CS and OC solvents alone was not significantly different from that observed with the tear gases themselves. The decrease in minute ventilation observed, between the second and the fifth minute of exposure, was of the same level for repeated exposure separated by 24 h. Time necessary to recover to 80% of pre-exposure minute ventilation was not significantly different between the two tear gases: 722+/-272 and 691+/-262 s for CS and OC respectively (NS). Histological analysis of the trachea, performed at the end of exposures, revealed an increase in mucus secretion after exposure to OC and cytoplasmic vacuoles in epithelial cells after exposure to CS. In the lungs, interstitial oedema was observed after exposure to OC and emphysema after exposure to CS.

Quantitative and qualitative studies of micronucleus induction in mouse erythrocytes using flow cytometry. I. Measurement of micronucleus induction in peripheral blood polychromatic erythrocytes by chemicals with known and suspected genotoxicity

Quantitative and qualitative aspects of the in vivo micronucleus-inducing potential of five chemicals were studied using flow cytometric enumeration of micronucleated polychromatic peripheral blood erythrocytes in mice. The chemicals were hydroquinone, vinblastine sulphate, chloral hydrate (tested in two different mouse strains), 5-bromo-2-deoxyuridine and 2-chlorobenzylidene malonitrile. Repeat samplings of peripheral blood were made at 0, 24, 40, 48 and 72 h and for low doses of 5-bromo-2-deoxyuridine 96 h after i.p. treatment. The agents hydroquinone (lowest effective dose 25 mg/kg), vinblastine sulphate (lowest effective dose 0.05 mg/kg) and 5-bromo-2-deoxyuridine (lowest effective dose 200 mg/kg) gave rise to significant increases in the frequencies of micronucleated polychromatic erythrocytes. No significant induction of micronucleated polychromatic erythrocytes by 2-chlorobenzylidene malonitrile or chloral hydrate was found. The frequencies of induced micronucleated polychromatic erythrocytes peaked at 40 h after hydroquinone treatment, at 48 h after vinblastine treatment and at 72 h after 5-bromo-2-deoxyuridine treatment with evident dose-dependent differences in the kinetics of the induction of micronucleated polychromatic erythrocytes. The mean relative Hoechst 33342 fluorescence of the populations of induced micronucleated polychromatic erythrocytes was used as an indicator of the DNA content of induced micronuclei. These values were found to be in agreement with the presumed mechanisms of micronucleus induction for hydroquinone, vinblastine sulphate and 5-bromo-2-deoxyuridine. Flow cytometric enumeration of micronucleated polychromatic erythrocytes in peripheral blood is an efficient method for the study of in vivo micronucleus induction, combining rapid analysis and high sensitivity with information on possible mechanisms of micronucleus induction. The method also allows a substantial reduction in the number of animals needed.

Induction of cell cycle perturbations by the tear gas 2-chlorobenzylidene malonitrile in synchronously and asynchronously proliferating mammalian cells

The effects of the tear gas 2-chlorobenzylidene malonitrile (CS) on mammalian cell proliferation were studied in detail using bromodeoxyuridine/Hoechst flow cytometry. In synchronized (G0/G1-phase) Chinese hamster embryo (CHE) cells, exposure to CS (60 microM) caused a permanent arrest in the G0/G1 phase in 50% of the cells and a delayed G0/G1 phase exit. In asynchronously growing CHE cells, the CS-induced cell kinetic perturbations varied with the cell cycle stage during treatment. While G1-phase cells showed a delayed progression through S and G2/M phases, S-phase cells were mainly inhibited in the G2/M compartment of the first cell cycle. In contrast, CS-treated, asynchronous, amniotic fluid-derived, fibroblast-like (AFFL) cells exhibited a prolonged transit through the G2/M phase of the first cell cycle regardless of the cell cycle stage during treatment. This indicates that the induced cytotoxicity of CS is a function of both the cell cycle phase and the particular type of cells.

[Assessment of health effects of CS gas]

O-chlorobenzylidene malononitrile (CS) gas or aerosol is by no means a harmless tear-gas, as often is described; in particular, CS is a very effective irritating war gas. The effects of CS on humans are relatively unknown because publications in this respect are mostly on military medical research, partly classified as secret, and brought to the knowledge of a small number of experts only. CS is highly soluble in water, and hence the effects in police water jets are very low. The efficacy of CS-containing water-jetting consists only in the pressure of the jet stream. Medically, in police use, CS is therefore considered to be harmless. Military medical research results, however, show that persons older than 30 years, those under physical strain, and those with hitherto undetected aneurysm are especially at risk.

Mutagenicity evaluation of riot control agent o-chlorobenzylidene malononitrile (CS) in the Ames Salmonella/microsome test

o-Chlorobenzylidene malononitrile (CS), a riot control agent, was evaluated for its possible mutagenic activity in the Ames Salmonella/mammalian microsome mutagenicity test. Five histidine-deficient (His-) mutant tester strains of Salmonella typhimurium--TA97a, TA98, TA100, TA102 and TA104--were used. The liquid preincubation procedure was used with metabolic activation (presence of S9 mixture) and without metabolic activation (absence of S9 mixture). For the experiments with metabolic activation, three different concentrations of S9 fraction (supernatant of Aroclor 1254-induced rat liver homogenate at 9000 g)--5%, 15% and 30% in S9 mixture--were used. Along with mutagenic activity, CS was also evaluated for cytotoxic activity in all the five tester strains of Salmonella typhimurium, both in the presence and absence of S9 mixture. The mutagenic and cytotoxic activities of CS were assessed by counting the His+ revertant colonies and by counting the microcolonies (His-, auxotrophs in the background lawn), respectively, and the respective mean values were compared with the relative negative (solvent) control. A dose range of 12.5-800 micrograms plate-1 for CS did not induce a mutagenic response either in the presence or absence of S9 mix. No change in the negative mutagenic response of CS has been observed even in the presence of an elevated level of S9 fraction in the S9 mix. A dose of 200 micrograms plate-1 for CS was found to be cytotoxic by decreasing the surviving cells as well as His+ revertant colonies; however, the effect was reduced in the presence of an elevated level of S9 fraction in the S9 mix.

Clastogenicity of 2-chlorobenzylidene malonitrile (CS) in V79 Chinese hamster cells

The clastogenicity of the sensory irritant 2-chlorobenzylidene malonitrile (CS) to V79 Chinese hamster cells was investigated at various exposure conditions. CS efficiently induced chromatid-type aberrations in a dose-dependent manner provided the cells could run through at least one or two S-phases during a 20-h exposure over a 3-h exposure followed by a 20-h recovery period (cell cycle time 8-10 h). The induction of SCEs indicates an S-dependent mechanism. The hydrolysis products o-chlorobenzaldehyde and malonitrile were inactive in these experiments.

Analysis of the aneuploidy inducing capacity of 2-chlorobenzylidene malonitrile (CS) and metabolites in V79 Chinese hamster cells

The aneuploidy inducing capacity of 2-chlorobenzylidene malonitrile (CS), a chemical used as a riot control agent, and its hydrolysis products o-chlorobenzaldehyde and malonitrile was studied at various exposure conditions in V79 Chinese hamster cells. Chromosomes were counted in metaphase preparations with preserved cytoplasm. A significant increase in the number of aneuploid cells was found after CS and o-chlorobenzaldehyde exposure but not after malonitrile exposure. o-chlorobenzaldehyde, which also introduced high levels of polyploid cells, seems to be an important metabolite for the aneuploidogenic effectiveness of CS.

Mitotic spindle damage induced by 2-chlorobenzylidene malonitrile (CS) in V79 Chinese hamster cells examined by differential staining of the spindle apparatus and chromosomes

A 3-h exposure of V79 Chinese hamster cells with the sensory irritant 2-chlorobenzylidene malonitrile (CS) caused apolar mitoses in a dose-dependent manner. With a preparation and staining technique that allows for the visualization of the spindle apparatus and the chromosomes it was found that unlike in Colcemid-induced c-metaphases residual spindle fibers or microtubule material were present in the majority of CS-induced c-metaphases. The observation suggests different mechanisms for the induction of the c-mitotic effect by the two spindle poisons.

Tear gas--harassing agent or toxic chemical weapon?

Tear gas has gained widespread acceptance as a means of controlling civilian crowds and subduing barricaded criminals. The most widely used forms of tear gas have been o-chlorobenzylidenemalononitrile and omega-chloroacetophenone. Proponents of their use claim that, if used correctly, the noxious effects of exposure are transient and of no long-term consequences. The use of tear gas in recent situations of civil unrest, however, demonstrates that exposure to the weapon is difficult to control and indiscriminate, and the weapon is often not used correctly. Severe traumatic injury from exploding tear gas bombs as well as lethal toxic injury have been documented. Moreover, available toxicological data are deficient as to the potential of tear gas agents to cause long-term pulmonary, carcinogenic, and reproductive effects. Published and recent unpublished in vitro tests have shown o-chlorobenzylidenemalononitrile to be both clastogenic and mutagenic. Sadly, the nature of its use renders analytic epidemiologic investigation of exposed persons difficult. In 1969, eighty countries voted to include tear gas agents among chemical weapons banned under the Geneva Protocol. There is an ongoing need for investigation into the full toxicological potential of tear gas chemicals and renewed debate on whether their use can be condoned under any circumstances.

Mutagenicity and cytotoxicity of 2-chlorobenzylidene malonitrile (CS) and metabolites in V79 Chinese hamster cells

The genotoxicity of the sensory irritant 2-chlorobenzylidene malonitrile (CS) to V79 Chinese hamster cells was investigated using the induction of gene mutations, micronuclei and DNA repair synthesis as biological endpoints. CS efficiently induced micronuclei and mutants resistant to 6-thioguanine in these cells, but it did not elicit DNA repair synthesis. Induction of micronuclei and mutants showed very similar courses of concentration dependence, suggesting that both events were caused by the same mechanism. The hydrolysis products of CS, o-chlorobenzaldehyde and malononitrile dit not induce micronuclei and were much less cytotoxic than CS. The observation of heritable genetic changes in cells exposed to CS in the absence of detectable DNA damage suggests that the genetic effects of CS are not caused by an interaction of the compound or its hydrolysis products with DNA. It appears more likely that the mutagenic activity is the consequence of effects of CS on the mitotic apparatus of the cells causing chromosomal aneuploidy.

2-Chlorobenzylidene malonitrile (CS) causes spindle disturbances in V79 Chinese hamster cells

Exposure of V79 Chinese hamster cells to 2-chlorobenzylidene malonitrile (CS), a chemical used as a sensory irritant for riot control, caused a concentration-dependent increase in the incidence of spindle disturbances. A C-mitotic effect with the appearance of C-metaphases, a metaphase block and the concomitant disappearance of ana-telophase figures were observed after a 3-h treatment. The results indicate that CS might induce aneuploidy in mammalian cells by interacting with the mitotic apparatus.

Chemical irritant algesia assessed using the human blister base

The chemical irritants o-chlorobenzylidene malononitrile (CS), n-nonanoylvanillylamine (VAN) and dibenzoxazepine (CR) and several of its derivatives have been assayed using the human blister base. The relative potencies found by this method, CR greater than VAN greater than CS, conflicted with those found in non-human test systems but the rank order of potency of CS and CR reflected that reported in tests on the human eye and tongue. Data derived from humans thus appear to be of importance when assessing irritant potency. Interactions between CS, CR, VAN, capsaicin and bradykinin were investigated to discover any common pathways of irritant activity. Self-desensitization developed on repeated application of all agents to the blister base and selective cross-desensitization also occurred.

Acute toxicity and primary irritancy of 2-amino-3,5-dicyano-4-o-chlorophenyl-6-ethoxypyridine

2-Amino-3,5-dicyano-4-o-chlorophenyl-6-ethoxypyridine (ACCPE) is a water soluble compound formed during the alkaline treatment of the alcoholic liquor in the production of 2-chlorobenzylidene malononitrile (CS). The acute toxicity and primary irritancy of ACCPE and CS were investigated and compared. Both perorally and intravenously, ACCPE was significantly less acutely toxic than CS. Also, whilst CS was a moderate dermal and eye irritant, ACCPE was not a primary skin irritant and only marginally irritating to the eye. ACCPE presents a significantly lower acute handling hazard than does CS.

2-Chlorobenzylmercapturic acid, a metabolite of the riot control agent 2-chlorobenzylidene malononitrile (CS) in the rat

Adult male Wistar rats administered i.p. with 2-chlorobenzylidene malononitrile (CS) excreted one mercapturic acid in urine. The amount of mercapturic acid determined gaschromatographically was about 4% of the dose (0.07 mmol/kg, n = 12). The structure of the mercapturic acid methylester was identified by t.l.c. and confirmed by synthesis and mass-spectrography. The acid appeared to be 2-chlorobenzylmercapturic acid [N-acetyl-S-(2-chlorobenzyl)-L-cysteine]. CS and some of its metabolites were also tested in the Ames Salmonella/microsome assay. Both mutagenic and toxic effects were measured with strain TA 100 as the indicator organism. No mutagenic effects were found with any of the tested substances. At dosages of CS, higher than 1,000 micrograms/plate a bacteriotoxicity was revealed.

Genotoxicity study of CS (ortho-chlorobenzylidenemalononitrile) in Salmonella, Drosophila, and mice. Failure to detect mutagenic effects

The lacrimatory agent CS was examined for genotoxic properties. In vitro, Salmonella typhimurium was exposed to CS at concentrations up to 1.5 mg per plate and reverse mutations were assayed. In vivo: male Drosophilae were fed with CS and sex-linked recessive lethal mutations in sperm cells were assayed using the Basc test. Further, mice were exposed to CS by oral or intraperitoneal administration; bone marrow erythrocytes were analysed for chromosomal mutations by means of the micronucleus test. All experiments failed to show a mutagenic activity of CS.

A repeated dose study of the toxicity of inhaled 2-chlorobenzylidene malononitrile (CS) aerosol in three species of laboratory animal

The repeated dose inhalation toxicity of 2-chlorobenzylidene maloninitrile (CS) was investigated in male mice, rats, and guinea-pigs. Exposure was 1 h X day-1 for 120 days surviving animals being killed approximately 1 year after the start of exposure. Excess mortality was noted in the high dose groups of all three species but at exposure concentrations below 30 micrograms X 1(-1) mortality varied little between the control and test groups. Death during the experiment was related to concentration of exposure rather than total dose (Ct). No case of a dose-response relationship between tumours in a particular site, and total dose of CS was noted.

Short-term toxicity studies of O-chlorobenzylidene malononitrile on humoral immunity in mice

The effect of O-chlorobenzylidene malononitrile (CS) on the immune system was studied in mice given 8 and 16 mg/kg body weight i.p. of the compound, daily for 10 days. The humoral immune response to SRBC was suppressed at both doses, as determined by the antibody producing cells in the spleen. To find out whether the immunosuppression observed was due to the indirect effect of CS on the nutritional status and endocrine balance, serum proteins and corticosterone levels were measured. While the serum proteins did not alter, corticosterone levels rose significantly only in mice receiving higher dose of CS.

The comparative acute mammalian toxicity of 1-chloroacetophenone (CN) and 2-chlorobenzylidene malononitrile (CS)

The comparative acute toxicity of two peripheral sensory irritant materials, 1-chloroacetophenone (CN) and 2-chlorobenzylidene malononitrile (CS), has been investigated in several species of small mammal using solutions in polyethylene glycol 300 for intravenous, intraperitoneal and oral administration, and as pure aerosols for inhalation exposure. Additionally, the comparative potency for inducing primary contact dermatitis was studied. CN and CS were found to be about equitoxic by intravenous and intraperitoneal injection, but CS was significantly less toxic by the oral and inhalation routes and less likely to cause non-lethal tissue damage than CN.

The acute mammalian toxicology of dibenz(b,f)-1,4-oxazepine

Dibenz(b,f)-1,4-oxazepine (CR), a potent peripheral sensory irritant material, has been shown to have a very low acute lethal and sub-lethal toxicity by intravenous, intraperitoneal, oral, percutaneous and inhalation routes to several species of laboratory mammal. There was no organ-specific pathology. Comparison of the acute toxicity of CR with that of two other peripheral sensory irritants, 1-chloroacetophenone (CN) and 2-chlorobenzyl-lidene malononitrile (CS), shows CR to be significantly less toxic than either of them. Pyrotechnically generated CR smoke was more toxic than pure (thermally generated) aerosols of CR; this was due to the presence of pyrotechnic decomposition products in the atmosphere from the burning of the smoke generating composition. However, the median lethal toxicity of pyrotechnically generated CR smoke was very significantly less than that of either pyrotechnically generated CN or CS smokes. Short-term cumulative toxicity did not occur following multiple oral dosing with CR. The acute toxicology of three ether intermediates encountered in the synthesis of CR from 1-chloro-2-nitrobenzene and sodium phenoxide (2-nitrodiphenyl ether, 2-aminodiphenyl ether and 2-formamidodiphenyl ether) was investigated; all three ethers were found to be less acutely toxic than CR itself.