o-Chlorobenzylidene malononitrile

CAS number: 2698–41–1

NIOSH REL: 0.05 ppm (0.4 mg/m³) CEILING [skin]

Current OSHA PEL: 0.05 ppm (0.4 mg/m³) TWA

1989 OSHA PEL: 0.05 ppm (0.4 mg/m³) CEILING [skin]

1993-1994 ACGIH TLV: 0.05 ppm (0.39 mg/m³) CEILING [skin]

Description of Substance: White crystalline solid with a pepper-like odor.

LEL: . . Unknown

Original (SCP) IDLH: 2 mg/m³

Basis for original (SCP) IDLH: The chosen IDLH is based on the Army [1961] report that a 2-minute exposure to concentrations between 2 and 10 mg/m³ was considered "intolerable" by 6 of 15 persons. Grant [1974] reported that human volunteers have found concentrations greater than 10 mg/m³ to be extremely irritating, intolerable for more than 30 seconds because of burning and pain in the eyes and chest [Punte et al. 1963].

Short-term exposure guidelines: None developed

ACUTE TOXICITY DATA

Lethal concentration data:

Species	Reference	LC50 (ppm)	LCLo (ppm)	Time	Adjusted 0.5-hr LC (CF)	Derived value
Rat Mouse Rabbit G. pig	Ballantyne and Swanston 1978 Ballantyne and Swanston 1978 Ballantyne and Swanston 1978 Ballantyne and Swanston 1978	----- ----- ----- -----	1,806 mg/m3 2,753 mg/m3 1,802 mg/m3 2,326 mg/m3	45 min 20 min 10 min 10 min	2,059 mg/m3 (1.14) 2,643 mg/m3 (0.96) 1,243 mg/m3 (0.69) 1,605 mg/m3 (0.69)	206 mg/m3 264 mg/m3 124 mg/m3 161 mg/m3

Other animal data: RD₅₀(mouse), 4.08 mg/m³ [Alarie 1981].

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 2-minute 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].

Revised IDLH: 2 mg/m3 [Unchanged] Basis for revised IDLH: Based on acute inhalation toxicity data in human volunteers [Army 1961; Punte et al. 1963; U.S. Depts of Army and Air Force 1963; Weigand 1969], the original IDLH for o-chlorobenzylidene malononitrile (2 mg/m3) is not being revised at this time.

REFERENCES:

1. Alarie Y [1981]. Dose-response analysis in animal studies: prediction of human responses. Environ Health Perspect 42:9-13.

2. Army [1961]. U.S. Army, Chemical Corps Safety Directive No. 385-12. Safety guide for processing, filling, handling and decontamination of CS and CS1. Edgewood Arsenal, MD: CML C SD-385-12, p. 4.

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

4. Grant WM [1974]. Toxicology of the eye. 2nd ed. Springfield, IL: C.C. Thomas, pp. 263-264.

5. Punte CL, Owens EJ, Gutentag PJ [1963]. Exposures to ortho-chlorobenzylidene malononitrile: controlled human exposures. Arch Environ Health 6:366-374.

6. U.S. Departments of the Army and Air Force [1963]. Military chemistry and chemical agents. Washington, DC: Army Technical Manual TM3-215; Air Force Manual AFM 355-7, December 1963.

7. Weigand DA [1969]. Cutaneous reaction to the riot control agent CS. Milit Med 134:437.