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Thallium (soluble compounds, as Tl)

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

CAS number: Varies

NIOSH REL: 0.1 mg/m3 TWA [skin]

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

1989 OSHA PEL: Same as current PEL

1993­1994 ACGIH TLV: 0.1 mg/m3 TWA [skin]

Description of substance: Varies

Original (SCP) IDLH*: 20 mg TI/m3

Basis for original (SCP) IDLH: Because no data on acute inhalation toxicity are available on which to base the IDLH for the soluble compounds of thallium, research in this area is needed. The chosen IDLH has been estimated from the data given by; ACGIH [1971] that LD50 values for different thallium compounds, by various routes of administration and for several species of animals ranged from 3 to 92 mg/kg [Downs et al. 1960 as cited by Patty 1963]. Further support for the chosen IDLH can be gained from the statement by Deichmann and Gerarde [1969] that a dose of 0.2 gram (inorganic salts of thallium) may be lethal unless treatment if started promptly.

ShortShort­term exposure guidelines: None developed


Lethal dose data:

Species Reference Route LD50 (mg/kg) LDLo (mg/kg) Adjusted LD Derived value
Tikhova 1964 oral 24 —– 143 mg Tl/m3 14 mg Tl/m3
Gekkan Yakuji 1980 oral 16 —– 91 mg Tl/m3 9.1 mg Tl/m3
Tikhova 1964 oral 23.5 —– 133 mg Tl/m3 13 mg Tl/m3
Kusano 1969 oral 35 —– 191 mg Tl/m3 19 mg Tl/m3
TlC2H3O 2 Rat Venugopal and Luckey 1978 oral 41.3 —– 225 mg Tl/m3 23 mg Tl/m3
Tikhova 1964 oral 21 —– 128 mg Tl/m3 13 mg Tl/m3
Tikhova 1964 oral —– 23 140 mg Tl/m3 14 mg Tl/m3

Human data : Lethal oral doses ranging from 0.9 to 9.4 mg/kg have been reported [Gekkan Yakuji 1980; Tanaka et al. 1978; Venugopal and Luckey 1978; Yakkyoku 1977]. [Note: an oral dose ranging from 0.9 to 9.4 mg/kg is equivalent to a 70-kg worker being exposed to concentrations ranging from about 40 to 450 mg/m3 for 30 minutes, assuming a breathing rate of 50 liters per minute and 100% absorption.]


1. ACGIH [1971]. Thallium. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, p. 256.

2. Deichmann WB, Gerarde HW [1969]. Thallium. In; Toxicology of drugs and chemicals. New York, NY: Academic Press, Inc., pp. 582-583.

3. Downs WL, Scott JK, Steadman LT, Maynard EA [1960]. Acute and sub-acute toxicity studies of thallium compounds. Am Ind Hyg Assoc J 21:399-406.

4. Gekkan Yakuji (Pharmaceuticals Monthly) [1980]; 22:291-298 (in Japanese).

5. Kusano T [1969]. Studies on the improved effectiveness of anticoagulative rodenticides on rodents. I. Synergistic toxic action between coumarin or indandione derivatives and thallium salts on mice. Journal of the Faculty of Agriculture, Tottori University 5(2):15-52.

6. Patty FA, ed. [1963]. Industrial hygiene and toxicology. 2nd rev. ed. Vol. ll. Toxicology. New York, NY: Interscience Publishers, Inc., p. 1140.

7. Tanaka J. Yonezawa T. Ueyama M [1978]. Acute thallotoxicosis: neuropathological and spectrophotometric studies on an autopsy case. J Toxicol Sci 3:325-334.

8. Tikhova TS [1964]. Problems of labor hygiene in the production of metallic thallium and its salts. Gig Sanit 29(2):26-32 (translated).

9. Venugopal B. Luckey TD [1978]. Metal toxicity in mammals. Vol. 2. Chemical toxicity of metals and metalloids. New York, NY: Plenum Press, p. 101.

10. Yakkyoku (Pharmacy) [1977]; 28:329 (in Japanese).