Agent Name

o-Chlorobenzylidene malonitrile

CAS Number

2698-41-1

Formula

C10-H5-Cl-N2

Major Category

Toxic Gases & Vapors

Synonyms

((2-Chloro-phenyl)methylene)propanenitrile; (o-Chlorobenzal)malononitrile; (o-Chlorobenzylidene)malononitrile; 2-Chlorobenzalmalononitrile; 2-Chlorobenzylidene malonitrile; 2-Chlorobenzylidene malononitrile; 2-Chlorobenzylidenemalononitrile; 2-Chlorobmn; Alonitrile; CS; CS (lacrimator); Malononitrile, (o-chlorobenzylidene)-; Propanedinitrile, ((2-chlorophenyl)methylene); TL 238; beta,beta-Dicyano-o-chlorostyrene; chlorobenzylidenemalononitrile; o-Chlorobenzylidene malonitrile; o-Chlorobenzylidene malononitrile; o-Chlorobenzylidenemalonic nitrile; ortho-Chlorobenzylidene malononitrile; OCBM; [ChemIDplus] UN2811

Category

Tear Gas Agents

Description

White crystalline solid with a pepper-like odor; [NIOSH]

Sources/Uses

Occupational exposures can occur during the manufacturing and formulation of OCBM for a riot control agent; [NIOSH Guidelines for Chemical Hazards]

Comments

This is the active ingredient in the "CS" type of tear gas. No CS-related deaths have been reported. [NIOSH Guidelines for Chemical Hazards] Workers who handle CS during production have a significant risk of allergic contact dermatitis. [ACGIH] A lachrymator; [HSDB] A skin sensitizer; Severely irritating to the eyes, skin, and respiratory tract; [ICSC]

Exposure Assessment
Skin Designation (ACGIH)

Yes

Ceiling (ACGIH)

0.05 ppm

PEL (OSHA)

0.05 ppm

Excerpts from Documentation for IDLHs

Human data: It has been reported that median incapacitating concentrations range from 12 to 20 mg/m3 after about 20 seconds of exposure [U.S. Depts of Army and Air Force 1963] and that a 2minute exposure to concentrations between 2 and 10 mg/m3 was considered "intolerable" by 6 of 15 persons [Army 1961]. In another study, 3 of 4 volunteers exposed to 1.5 mg/m3 for 90 minutes developed headaches and 1 volunteer developed slight eye and nose irritation; human volunteers have found concentrations greater than 10 mg/m3 to be extremely irritating and intolerable for more than 30 seconds because of burning and pain in the eyes and chest [Punte et al. 1963]. Exposures above 14 mg/m3 for 1 hour produced extreme irritation, erythema, and vesication of the skin of volunteers [Weigand 1969].

Vapor Pressure

3.0E-5 mm Hg

RD50

4 ppm

Lethal Concentration

LCLo (rat) = 1,806 mg/m3/45M

Adverse Effects
Skin Sensitizer

Yes

Lacrimator

Yes

ACGIH Carcinogen

Not Classifiable

Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information

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Chemical Information

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Biomedical References

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Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent: