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May 1994
Immediately Dangerous to Life or Health Concentrations (IDLH)

CAS number: 8065–48–3

NIOSH REL: 0.1 mg/m3 TWA [skin]

Current OSHA PEL: 0.1 mg/m3 TWA [skin]

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.11 mg/m3 (0.01 ppm) TWA [skin]

Description of Substance: Amber, oily liquid with a sulfur-like odor.

LEL:. . Unknown

Original (SCP) IDLH: 20 mg/m3

Basis for original (SCP) IDLH: No useful data on acute inhalation toxicity are available on which to base the IDLH for demeton. The chosen IDLH, therefore, has been based on an analogy with parathion which has an IDLH of 20 mg/m3.

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50 LCLo Time Adjusted 0.5-hrLC (CF) Derivedvalue
RatCat Izmerov et al. 1982Izmerov et al. 1982 ———- 15 mg/m315 mg/m3 4 hr4 hr 30 mg/m3 (2.0)30 mg/m3 (2.0) 3.0 mg/m33.0 mg/m3


Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derivedvalue


Gurevich et al. 1962Rosival et al. 1958

Schafer 1972







35 mg/m355 mg/m3

12 mg/m3

3.5 mg/m35.5 mg/m3

1.2 mg/m3


Other animal data: In a subchronic inhalation study, no signs of illness resulted from the first day of exposure to 3 mg/m3 for 2 hours, tremors were noted on the second day, lacrimation and more severe tremors on the third day, and 10 of the 17 rats died during the fourth day [Deichmann and Rakoczy 1955]. It has been reported that the acute oral and dermal toxicity of demeton in mammals is approximately the same as that of parathion; the American Conference of Governmental Industrial Hygienists TLV for demeton is based on an analogy to parathion [ACGIH 1991].

Human data: None relevant for use in determining the revised IDLH.

Revised IDLH: 10 mg/m3Basis for revised IDLH: The revised IDLH for demeton is 10 mg/m3 based on an analogy with parathion [ACGIH 1991] which has a revised IDLH of 10 mg/m3.



1. ACGIH [1991]. Demeton. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 385-386.

2. Deichmann WB, Rakoczy R [1955]. Toxicity and mechanism of action of systox. AMA Arch Ind Health 11:324-331.

3. Gurevich BA, Smetevin NE, Lubetsky KZ [1962]. On the question of toxicity of a new defoliant folex. Gig Sanit 27(8):97-99 (in Russian).

4. Izmerov NF, Sanotsky IV, Sidorov KK [1982]. Toxicometric parameters of industrial toxic chemicals under single exposure. Moscow, Russia: Centre of International Projects, GKNT, p. 52.

5. Rosival L, Selecky FV, Vrbovsky L [1958]. Akutna experimentalna otrava organofosforovymi insekticidmi. Bratislavske Lekarske Listy 38:151-160 (in Czechoslovakian).

6. Schafer EW [1972]. The acute oral toxicity of 369 pesticidal, pharmaceutical and other chemicals to wild birds. Toxicol Appl Pharmacol 21:315-330.