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

CAS number: 1300–73–8 (mixed isomers)

NIOSH REL: 2 ppm (10 mg/m3) TWA [skin]

Current OSHA PEL: 5 ppm (25 mg/m3) TWA [skin]

1989 OSHA PEL: 2 ppm (10 mg/m3) TWA [skin]

1993-1994 ACGIH TLV: 0.5 ppm (2.5 mg/m3) TWA [skin], A2

Description of substance: Pale-yellow to brown liquid with a weak, aromatic, amine-like odor.

LEL: . . 1.0% (10% LEL, 1,000 ppm)

Original (SCP) IDLH: 150 ppm

Basis for original (SCP) IDLH: The chosen IDLH is based on the mouse 7-hour LC50 of 149 ppm [von Oettingen et al. 1947 cited by ACGIH 1971].

Short-term exposure guidelines: None developed


Lethal concentration data:





TimeAdjusted 0.5-hr


Derived value
Mice (2,4-)von Oettingen et al. 1947149-----7 hr358 ppm (2.4)36 ppm

Lethal dose data:





Adjusted LDDerived value
RabbitDeichmann & Gerarde 1969oral-----600833 ppm83 ppm
RatTreon et al. 1949oral-----610847 ppm85 ppm
Rat (2,3-)Vernot et al. 1977oral-----9301,292 ppm129 ppm
Mouse (2,3-)Vernot et al. 1977oral-----1,0701,486 ppm149 ppm
Rat (2,4-)Vernot et al. 1977oral-----470653 ppm65 ppm
Mouse (2,4-)Vernot et al. 1977oral-----250347 ppm35 ppm
Rat (2,4-)Lindstrom et al. 1969oral-----1,2591,749 ppm175 ppm
Rat (2,5-)Vernot et al. 1977oral-----1,3001,806 ppm181 ppm
Mouse (2,5-)Vernot et al. 1977oral-----8401,167 ppm117 ppm
Rat (2,6-)Vernot et al. 1977oral-----1,2301,708 ppm171 ppm
Mouse (2,6-)Vernot et al. 1977oral-----710986 ppm99 ppm
Rat (2,6-)Short et al. 1983oral-----1,0501,458 ppm146 ppm
Rat (3,4-)Vernot et al. 1977oral-----8101,125 ppm113 ppm
Mouse (3,4-)Vernot et al. 1977oral-----710986 ppm99 ppm
Rat (3,5-)Vernot et al. 1977oral-----710986 ppm99 ppm
Mouse (3,5-)Vernot et al. 1977oral-----420583 ppm58 ppm

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

Revised IDLH: 50 ppm

Basis for revised IDLH: The revised IDLH for xylidine is 50 ppm based on acute toxicity data in animals [Deichmann and Gerarde 1969; Treon et al. 1949; Vernot et al. 1977; von Oettingen et al. 1947]. This may be a conservative value due to the lack of relevant acute toxicity data for workers.


1. ACGIH [1971]. Xylidine. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 282-283.

2. Deichmann WB, Gerarde HW [1969]. Xylidine (aminodimethylbenzene). Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., p. 637.

3. Lindstrom HV, Bowie WG, Wallace WG, et al. [1969]. The toxicity and metabolism of mesidine and pseudodocumidine in rats. J Pharmacol Exp Ther 167:223. [From ACGIH [1991]. Xylidine. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 1743-1745.]

4. Short CR, King C, Sistrunk PW, Kerr KM [1983]. Subacute toxicity of several ring-substituted dialkylanilines in the rat. Fundam Appl Toxicol 3(4):285-292.

5. Treon JF, Deichmann WB, Sigmon HE, Wright H, Witherup SO, Heyro FF, Kitzmiller KV, Kelnan C [1949]. The toxic properties of xylidine and monomethylaniline. I. The comparative toxicity of xylidine and monomethyaniline when administered orally or intravenously to animals or applied upon their skin. J Ind Hyg Toxicol 31:1-18.

6. Vernot EH, MacEwen ID, Haun GG, Kinkead ER [1977]. Acute toxicity and skin corrosion data for some organic and inorganic compounds and aqueous solutions. Toxicol Appl Pharmacol 42(2):417-423.

7. von Oettingen WF, Neal PA, Sievers RF, Svirbely JL, Monaco AR, Horecker BL, Yagoda H, Sweeney TR, Peterson DC, Alford WC, Hauff VB, Gay H [1947]. Xylidine (c,c-dimethylaniline): its toxicity and potential dangers as compared with those of aniline and an appraisal of the potential hazards from its use in blending gasoline. NIH Bulletin 188:88.

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