Selenium compounds (as Se)

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

CAS number: 7782–49–2 (Elemental)

NIOSH REL: 0.2 mg/m3 TWA

Current OSHA PE:L 0.2 mg/m3 TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 0.2 mg/m3 TWA

Description of substance: Varies

Original (SCP) IDLH*: Unknown [*Note: “Effective” IDLH = 100 mg Se/m3 — see discussion below.]

Basis for original (SCP) IDLH: ACGIH [1971] reported that the LD50 values of soluble selenium compounds (selenite and selenate) for various animals and by different routes of administration ranged from 1.5 to 5 mg/kg [Hall et al. 1951]. However, respirators have been selected based on the assigned protection factor afforded by each device up to 500 ´ the OSHA PEL of 0.2 mg Se/m3 (i.e., 100 mg Se/m3); only the “most protective” respirators are permitted for use in concentrations exceeding 100 mg Se/m3.

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50




Time Adjusted 0.5-hr


Derived value


Zapp 1946 ----- 5,890 mg/m3 20 min 3,638 mg Se/m3 (0.87) 364 mg Se/m3


Zapp 1946 ----- 6,590 mg/m3 10 min 3,228 mg Se/m3 (0.69) 323 mg Se/m3


Zapp 1946 ----- 6,590 mg/m3 10 min 3,228 mg Se/m3 (0.69) 323 mg Se/m3

Lethal dose data:

Species Reference Route LD50




Adjusted LD Derived value


Cummins &Kimura 1971 oral 6,700 ----- 46,900 mg Se/m3 4,690 mg Se/m3
SeO3×2Na Rat Cummins & Kimura 1971 oral 7 ----- 22 mg Se/m3 2.2 mg Se/m3
SeO3×2Na Pig Olson 1986 oral ----- 13 42 mg Se/m3 4.2 mg Se/m3
SeO3×2Na Cow Olson 1986 oral ----- 9.9 32 mg Se/m3 3.2 mg Se/m3
SeO3×2Na Goat Olson 1986 oral ----- 3.3 11 mg Se/m3 1.1 mg Se/m3
SeO3×2Na Sheep Olson 1986 oral ----- 3.3 11 mg Se/m3 1.1 mg Se/m3
SeO3×2Na Mouse Pletnikova 1970a oral 7.08 ----- 23 mg Se/m3 2.3 mg Se/m3
SeO3×2Na G. pig Pletnikova 1970a oral 5.06 ----- 16 mg Se/m3 1.6 mg Se/m3
SeO3×2Na Rabbit Pletnikova 1970b oral 2.25 ----- 7.2 mg Se/m3 0.7 mg Se/m3
SeO3×2Na Horse Stowe 1980 oral 13 ----- 42 mg Se/ m3 0.4 mg Se/m3


Wilber 1980 skin ----- 2 6.7 mg Se/m3 0.7 mg Se/m3

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

Revised IDLH: 1 mg Se/m3

Basis for revised IDLH: The revised IDLH for selenium compounds is 1 mg Se/m3 based on acute toxicity data in animals [Olson 1986; Pletnikova 1970a, 1970b]. This may be a conservative value for selenium compounds in general since it is based on sodium selenite, which is orders of magnitude more toxic than many other selenium compounds. Further, this may also be a conservative value due to the lack of relevant acute toxicity data for workers.


1. ACGIH [1971]. Selenium compounds (as Se). In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 224-225.

2. Cummins LM, Kimura ET [1971]. Safety evaluation of selenium sulfide antidandruff shampoos. Toxicol Appl Pharmacol 20:89-96.

3. Hall RH, Laskin S, Frank P, Maynard EA, Hodge HC [1951]. Preliminary observations on toxicity of elemental selenium. AMA Arch Ind Hyg Occup Med 4:458-464.

4. Olson OE [1986]. Selenium toxicity in animals with emphasis on man. J Am Coll Toxicol 5(1):45-70.

5. Pletnikova IP [1970a]. Biological action and the non-injuriousness level of selenium when it enters the organism together with drinking water. Gig Sanit 35(2):14-19 (in Russian).

6. Pletnikova IP [1970b]. Biological effect and safe concentration of selenium in drinking water. Gig Sanit 35(1-3):176-181 (translated).

7. Stowe HD [1980]. Effects of copper pretreatment upon the toxicity of selenium in ponies. Am J Vet Res 41(12):1925-1928.

8. Wilber CG [1980]. Toxicology of selenium: a review. Clin Toxicol 17:171-230.

9. Zapp JA [1946]. Chapter 11. Cadmium, selenium, and the carbonyls of iron and nickel. In: Summary technical report of division 9, NDRC. Vol 1. Chemical warfare agents and related chemical problems. Parts I-II. Washington, DC: National Defence Research Committee, pp. 173-178.

Page last reviewed: December 4, 2014