- Synonyms: Butanic acid; n-Butanoic Acid; Ethylacetic Acid; 1-Propanecarboxylic acid; Propylformic Acid
- OSHA IMIS Code Number: B709
- Chemical Abstracts Service (CAS) Registry Number: 107-92-6
- NIOSH Registry of Toxic Effects of Chemical Substances (RTECS) Identification Number: ES5425000
- Chemical Description and Physical Properties:
- colorless oily liquid, with characteristic odor
- molecular weight: 88.12
- vapor pressure: 57 Pa at 20°C
- molecular formula: C4H8O2
- boiling point: 164°C
- melting point: -7.9°C
- flash point: 72°C closed cup
- Potential Symptoms: Irritation of eyes, skin, throat; skin redness, pain, burns, blisters (from contact with liquid); cough, shortness of breath, labored breathing; eye redness, pain, burns, loss of vision (from liquid); Acute ingestion: Burning sensation, abdominal pain; shock or collapse.
- Health Effects: Irritation-Eyes, Nose, Throat, Skin---Marked (HE14)
- Affected Organs: Eyes, skin, respiratory system
- OSHA does not have a PEL for butyric acid.
- Explosive vapor/air mixtures of butyric acid may be formed at temperatures above 72°C.
- Butyric acid is listed by the FDA as a synthetic flavoring substance that is generally recognized as safe (GRAS) for its intended use (21 CFR 182.60).
- NIOSH reported butyric acid to be among the prominent volatile organic compounds (VOC) found in a commercial paste form of butter flavoring when heated to 50°C. VOC from butter flavorings have been causally implicated in occupational lung disease, including bronchiolitis obliterans (see also Diacetyl). However, no information was found regarding the health effects of chronic low-level inhalational exposure to butyric acid.
- Butyric acid is a potent uncompetitive inhibitor of human diacetyl reductase (IC50, 64 µM), a ubiquitous enzyme that has the capability of detoxifying diacetyl.
- Literature Basis:
- International Chemical Safety Cards (WHO/IPCS/ILO): Butyric acid.
- Boylstein, R., Piacitelli, C., Grote, A., Kanwal, R., Kullman, G. and Kreiss, K.: Diacetyl emissions and airborne dust from butter flavorings used in microwave popcorn production. J. Occup. Environ. Hyg. 3(10): 530-535, 2006.
- Nakagawa, J., et al.: Molecular characterization of mammalian dicarbonyl/L-xylulose reductase and its localization in kidney. J. Biol. Chem. 277(20): 17883-17891, 2002.
- Pohanish, R.P. (editor): Butyric Acid. In, Sittig's Handbook of Toxic and Hazardous Chemicals and Carcinogens, Fourth Ed., Vol. 1. Norwich, NY: Noyes Publications, William Andrew Publishing, 2002, pp. 429-431.
- Date Last Revised: 05/02/2007
Monitoring Methods used by OSHA
Primary Laboratory Sampling/Analytical Method (SLC1):
- Silica Gel Tube (520/260 mg sections; 20/40 mesh)
- maximum volume: 18 Liters
- maximum flow rate: 0.1 L/min
- current analytical method: Gas Chromatography; GC/FID
- analytical solvent: (1:99) Formic Acid:Water
- method reference: OSHA Salt Lake Technical (SLTC) Center In-House File
- method classification: Not Validated
Gilland, James C.; Johnson, Gary T.; McGee, William A. American Industrial Hygiene Association Journal Vol 42, 8, 630-2
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