<< Back to Chemical Sampling Information

Chemical Sampling Information (CSI)
Search (use word(s)/phrase)
Table of Contents
By Name

By CAS Number
Quick Links

General Description

Synonyms: Isovaleral; Isopentaldehyde; 3-Methylbutanal; 3-Methylbutyraldehyde

OSHA IMIS Code Number: I201

Chemical Abstracts Service (CAS) Registry Number: 590-86-3

NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: ES3450000

Chemical Description and Physical Properties:

molecular weight: 86.13
molecular formula: C5H10O
boiling point: 90°C
melting point: -51°C
flash point: -5°C

Health Factors

Potential Symptoms: Irritation of eyes, skin, mucous membranes, respiratory system; chest tightness, cough, dyspnea; dizziness, headache, lethargy, anorexia, nausea, vomiting, diarrhea; sweating; tachycardia

Health Effects: Irritation-Eyes, Nose, Throat, Skin---Moderate (HE15)

Affected Organs: Eyes, skin, respiratory system


  1. OSHA does not have a PEL for isovaleraldehyde. A safe level in the workplace of 10 ppm has been suggested on the basis of an aldehyde NOAEL of 50 ppm in rats.
  2. Isovaleraldehyde is listed (as 3-methylbutyraldehyde) by the FDA as a synthetic flavoring substance that is permitted for direct addition to food for human consumption (21 CFR 172.515), and it occurs naturally in various foods and flavorings (e.g., coffee, cheese, corn tortilla chips, and orange, lemon and eucalyptus oils).
  3. Its level in plasma can be increased by oral feeding of the amino acid leucine.
  4. In sensory irritation studies with mice, the RD50 (concentration decreasing respiratory rate in 10 minutes) for isovaleraldehyde was 757-1008 ppm.
  5. Inhalation of isovaleraldehyde at 6176 mg/m3 for 10 hours was lethal in 3/5 mice, 5/20 guinea pigs, and 0/5 rabbits.

Literature Basis:

  • Buttery, R.G. and Ling, L.C.: Additional studies on flavor components of corn tortilla chips. J. Agri. Food Chem. 46(7): 2764-2769, 1998.
  • Ford, R.A., Letizia, C. and Api, A.M.: 3-Methylbutyraldehyde. Food Chem. Toxicol. 26(4): 379-380, 1988.
  • Marshall, A.W., DeSouza, M. and Morgan, M.Y.: Plasma 3-methylbutanal in man and its relationship to hepatic encephalopathy. Clin. Physiol. 5(1): 53-62, 1985.
  • No authors listed: SIDS Initial Assessment Report for SIAM 10, 3-Methylbutanal (and) IUCLID Data Set, isovaleraldehyde [81 KB PDF, 52 pages]. UNEP Publications (2002).
  • Smit, B.A., Engels, W.J., Wouters, J.T. and Smit, G.: Diversity of L-leucine catabolism in various microorganisms involved in dairy fermentations, and identification of the rate-controlling step in the formation of the potent flavour component 3-methylbutanal. Appl. Microbiol. Biotechnol. 64(3): 396-402, 2004.
  • Steinhagen, W.H. and Barrow, C.S.: Sensory irritation structure-activity study of inhaled aldehydes in B6C3F1 and Swiss-Webster mice. Toxicol. Appl. Pharmacol. 72(3): 495-503, 1984.

Date Last Revised: 03/07/2007

Monitoring Methods used by OSHA

Primary Laboratory Sampling/Analytical Method (SLC1):

  • sampling media: Coated XAD-2 Tube (150/75 mg sections, 20/60 mesh); coating is 10% (w/w) 2-(Hydroxymethyl)piperidine
    analytical solvent: Toluene
    maximum volume: 5 Liters
    maximum flow rate: 0.05 L/min
    current analytical method: Gas Chromatography; GC/NPD with GC/MS identification
    method reference: OSHA Modified NIOSH Analytical Method (NIOSH 2539 [255 KB PDF, 10 pages])
    method classification: Partially Validated
    note: OSHA modification is use of GC/NPD in place of GC/FID. This is a screening method and is not quantitative.

  • sampling media: Silica gel tube coated with acidified 2,4-dinitro-phenyl hydrazine
    analytical solvent: Acetonitrile
    maximum volume: 15 Liters
    maximum flow rate: 1.5 L/min
    current analytical method: High Performance Liquid Chromatography, HPLC/UV
    method reference: NIOSH Analytical Method (NIOSH 2018 [127 KB PDF, 10 pages])
    method classification: Partially Validated

** All Trademarks are the property of their respective owners.

Accessibility Assistance: Contact the OSHA Directorate of Technical Support and Emergency Management at (202) 693-2300 for assistance accessing PDF materials.