IUPAC Name: 2-[(2-Chlorophenyl)methylidene]propanedinitrile
Molecular Formula: C₁₀H₅ClN₂
Molecular Weight: 188.61 g/mol
EINECS: 220-278-9
Density: 1.296 g/cm³
Flash Point: 148 °C
Melting point: 95 °C
Index of Refraction: 1.623
Surface Tension: 56.4 dyne/cm
Enthalpy of Vaporization: 55.35 kJ/mol
Boiling Point: 310-315 °C at 760 mmHg
Vapour Pressure: 0.000527 mmHg at 25 °C
Water Solubility:  0.1-0.5 g/100 mL at 16 °C 
Appearance: White crystalline solid or light beige powder
Following is the structure of O-Chlorobenzylidene malononitrile (CAS NO.2698-41-1):
      

 O-Chlorobenzylidene malononitrile (CAS NO.2698-41-1) malononitrile can be used as riot control agent. It is used primarily as an incapacitating agent, both by military & law enforcement personnel. It can be disseminated in burning grenades & weapon-fired projectiles, as an aerosol from the finely divided solid chemical, or from a solution of the chemical dissolved in methylene chloride or acetone.

 O-Chlorobenzylidene malononitrile (CAS NO.2698-41-1) was reported in EPA TSCA Inventory. Cyanide and its compounds are on the Community Right-To-Know List.

Poison by ingestion, intraperitoneal, and intravenous routes. Moderately toxic by inhalation. Human systemic effects by inhalation: conjunctiva irritation, cough, and unspecified respiratory system effects. A human skin and eye irritant. Human exposure data suggest relatively low systemic toxicity, but intense irritation of eyes, skin, and mucous membranes. Mutation data reported. A tear gas used for riot control. When heated to decomposition it emits very toxic fumes of Cl⁻, NO_x, and CN⁻.
Hazard Codes:  Xi,T
Risk Statements: 36/37/38-42/43-25 
R36/37/38:Irritating to eyes, respiratory system and skin. 
R42/43:May cause sensitization by inhalation and skin contact. 
R25 :Toxic if swallowed.
Safety Statements: 26-27-37/39-45-36/37/39 
S26: In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. 
S27:Take off immediately all contaminated clothing. 
S37/39:Wear suitable gloves and eye/face protection. 
S45:In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible.) 
S36/37/39:Wear suitable protective clothing, gloves and eye/face protection.
RIDADR: UN 3448 6.1/PG 2
RTECS:  OO3675000
WGK Germany: 3
HazardClass: 6.1(a)
PackingGroup: I 

OSHA PEL: CL 0.05 ppm (skin)
ACGIH TLV: CL 0.05 ppm (skin); Not Classifiable as a Human Carcinogen

 O-Chlorobenzylidene malononitrile , with a CAS name of 2698-41-1, it has some synonyms like 2-[(2-chlorophenyl)methylene]malononitrile or ((2-Chlorophenyl)methylene)propanedinitrile.
 O-Chlorobenzylidene malononitrile (CAS NO.2698-41-1) is hazardous, so the first aid measures and others should be known. Such as: When on the skin: first, should immediately flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water.Then, get medical aid. Or in the eyes: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously get medical aid. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. Immediately While, it's inhaled: Immediately leave the contaminated area; take deep breaths of fresh air.Then, get medical aid. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used. Then you have the ingesting of the product :  If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical. Get medical aid immediately. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. Do not induce vomiting. Transport the victim immediately to a hospital.