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Benzoyl peroxide

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

CAS number: 94-36-0

NIOSH REL: 5 mg/m3 TWA

Current OSHA PEL:5 mg/m3 TWA

1989 OSHA PEL: Same as current PEL

1993-1994 ACGIH TLV: 5 mg/m3 TWA

Description of Substance: Colorless to white crystals or a granular powder with a faint, benzaldehyde-like odor.

LEL: Unknown

Original (SCP) IDLH: 7,000 mg/m3

Basis for original (SCP) IDLH: The chosen IDLH is based on the estimated mouse 4-hour LC50 of 700 ppm (7,000 mg/m3) for benzoyl peroxide cited by ACGIH [1971]. However, this concentration is not an actual LC50 value for benzoyl peroxide; it was estimated by ACGIH [1971] by analogy from data concerning LC50 values for other related organic peroxides [Floyd and Stokinger 1958].

Short-term exposure guidelines: None developed


Lethal concentration data:

Species Reference LC50 LCLo Time Adjusted 0.5-hr LC (CF) Derived Value PPM
Mouse Floyd and Stokinger 1958 7,000 mg/m3 ----- 4 hr 14,000 mg/m3 (2.0) 1,400 mg/m3

Lethal dose data:

Species Reference Route LD50(mg/kg) LDLo(mg/kg) Adjusted LD Derived Value
Mouse ARCO 1982 oral 7,710 ----- 53,970 mg/m3 5,397 mg/m3

Human data: Concentrations of 12 mg/m3 and higher have resulted in pronounced irritation of the nose and throat [Moskowitz and Grabois 1950].

Revised IDLH: 1,500 mg/m3

Basis for revised IDLH: The revised IDLH for benzoyl peroxide is 1,500 mg/m3 based on acute inhalation toxicity data in animals [Floyd and Stokinger 1958].


  1. ACGIH [1971]. Acetaldehyde. In: Documentation of the threshold limit values for substances in workroom air. 3rd ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 23-24.
  2. ARCO [1982]. Toxicology report. 70% aqueous tertiary butyl hydroperoxide: acute toxicity evaluation. Newtown Square, PA: Arco Chemical Company, June 1982.
  3. Floyd EP, Stokinger HE [1958]. Toxicity studies of certain organic peroxides and hydroperoxides. Am Ind Hyg Assoc J 19:205-212.
  4. Moskowitz S, Grabois B [1950]. Unpublished report sent to ACGIH. Albany, NY: New York State Department of Labor, Division of Industrial Hygiene (November 1950). [From ACGIH [1991]. Benzoyl peroxide. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. Cincinnati, OH: American Conference of Governmental Industrial Hygienists, pp. 123-124.]