2-Butanone oxime

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SMALL SPILLS AND LEAKAGE: If you should spill this chemical, use absorbent paper to pick up all liquid spill material. Seal the absorbent paper, as well as any of your clothing which may be contaminated, in a vapor-tight plastic bag for eventual disposal. Wash any surfaces you may have contaminated with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

8.0 [ppm]

150 [ppm]

880 [ppm]

RECOMMENDED RESPIRATOR: Where the neat test chemical is weighed and diluted, wear a NIOSH-approved half face respirator equipped with an organic vapor/acid gas cartridge (specific for organic vapors, HCl, acid gas and SO2) with a dust/mist filter. (NTP, 1992)

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 116(SRC), determined from a structure estimation method(2), indicates that 2-butanone oxime is expected to have high mobility in soil(SRC). Volatilization of 2-butanone oxime from moist soil surfaces is expected to occur(SRC) given a an estimated Henry's Law constant of 1.22X10-6 atm-cu m/mole(SRC), estimated from its vapor pressure, 1.06 mm Hg at 20 °C(3), and water solubility, 1X10+5 mg/L(4). 2-Butanone oxime is expected to volatilize from dry soil surfaces based upon its vapor pressure(SRC). A 14-19.6% theoretical BOD over a 2-week period(5) and a 24.7% theoretical BOD over a 4-week period(6) using activated sludge in the Japanese MITI test(3,6) suggests that biodegradation may occur in soil(SRC). [

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 116(SRC), determined from a structure estimation method(2) indicates that 2-butanone oxime is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is expected to occur(3) based upon an estimated Henry's Law constant of 1.22X10-6 atm-cu m/mole(SRC), derived from its vapor pressure, 1.06 mm Hg(4), and water solubility, 1X10+5 mg/L(5). Using this Henry's Law constant and an estimation method(3), volatilization half-lives for a model river and model lake are 28 and 208 days, respectively(SRC). According to a classification scheme(6), an observed BCF range of 0.5 to 5.8 in catfish over a 6-week test period(7), suggests the potential for bioconcentration in aquatic organisms is low. A 14-19.6% theoretical BOD over a 2-week period(8) and a 24.7% theoretical BOD over a 4-week period(7) using activated sludge in the Japanese MITI test(7-8) suggests that biodegradation may occur in water(SRC).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-butanone oxime, which has a vapor pressure of 1.06 mm Hg at 20 °C(2) is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 2-butanone oxime is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 11 days(SRC), calculated from its rate constant of 1.48X10-12 cu cm/molecule-sec at 25 °C(SRC) that was derived using a structure estimation method(2).

The following link will take the user to the National Toxicology Program (NTP) Test Agent Search Results page, which tabulates all of the "Standard Toxicology & Carcinogenesis Studies", "Developmental Studies", and "Genetic Toxicity Studies" performed with this chemical. Clicking on the "Testing Status" link will take the user to the status (i.e., in review, in progress, in preparation, on test, completed, etc.) and results of all the studies that the NTP has done on this chemical.[Available from, as of June 21, 2012: http://ntp-apps.niehs.nih.gov/ntp_tox/index.cfm?fuseaction=ntpsearch.searchresults&searchterm=96-29-7]

Using a structure estimation method based on molecular connectivity indices(1), the Koc of 2-butanone oxime can be estimated to be 116(SRC). According to a classification scheme(2), this estimated Koc value suggests that 2-butanone oxime is expected to have high mobility in soil.

2-Butanone oxime's production and use as an anti-skinning agent in paints and lacquers, as a blocking-agent for isocyanate in polyurethanes, and in the manufacture of oxime silanes for use as a crosslinking agent for silicone sealants(1) may result in its release to the environment through various waste streams(SRC).

AEROBIC: 2-Butanone oxime, present at 30 mg/L, reached 24.7% of its theoretical BOD in 4 weeks using an activated sludge inoculum at 100 mg/L in the Japanese MITI test(1). 2-Butanone oxime, present at 30 mg/L, reached 14-19.5% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 100 mg/L in the Japanese MITI test(2).

The Henry's Law constant for 2-butanone oxime is estimated as 1.22X10-6 atm-cu m/mole(SRC) derived from its vapor pressure, 1.06 mm Hg at 20 °C(1), and water solubility, 1X10+5 mg/L(2). This Henry's Law constant indicates that 2-butanone oxime is expected to volatilize slowly from water surfaces(3). Based on this Henry's Law constant, the volatilization half-life from a model river (1 m deep, flowing 1 m/sec, wind velocity of 3 m/sec)(3) is estimated as 28 days(SRC). The volatilization half-life from a model lake (1 m deep, flowing 0.05 m/sec, wind velocity of 0.5 m/sec)(3) is estimated as 208 days(SRC). 2-Butanone oxime's Henry's Law constant indicates that volatilization from moist soil surfaces may occur(SRC). 2-Butanone oxime expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(SRC). In two-week chamber studies using paints containing 2-butanone oxime, an average of 84% of the 2-butanone oxime in the paints initially was recovered in the volatile emissions(4).

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Male CD-1 mice were exposed 6 hr/day, 5 days/wk, for 1, 2, 4, or 13 wk via whole-body inhalation exposures to MEKO vapor concentrations of 0, 3 +/- 0.1, 10 +/- 0.3, 30 +/- 1, or 100 +/- 2 ppm (10 mice/group/interval). Satellite animals were removed after 1, 2, 4, or 13 wk of exposure and allowed to recover for 4 or 13 wk (5 mice/group/interval). After termination, the nasal turbinates were evaluated microscopically, and cross-sectional nasal maps of the lesions were prepared. At the end of the 1-, 2-, 4-, and 13-wk exposure periods, degeneration of the olfactory epithelium lining the dorsal meatus was seen in the anterior region of the nasal cavity. In a few instances, the olfactory epithelium covering the tips of the nasoturbinal scrolls projecting into the dorsal region of the nasal cavity was also degenerated. Large areas of olfactory epithelium lying laterally and posteriorly were unaffected. In general, approximately 10% or less of the total olfactory tissue was affected. In several instances, the degenerated olfactory epithelium was reepithelialized by squamous/squamoid and/or respiratory types of epithelium. Degeneration, which was dose related in incidence and severity, was seen in mice exposed to 30 and 100 ppm after 1 wk of exposure and in several mice exposed to 10 ppm after 13 wk of exposure. The incidence and severity of the degeneration present after 1 wk of exposure did not increase with the longer exposures. The olfactory degeneration was reversible. Recovery was complete within 4 wk following exposures at 10 ppm and nearly complete within 13 wk after exposures at 30 and 100 ppm. A no-observed-effect level (NOEL) for the olfactory degeneration was considered to be 3 ppm.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ /Fischer 344/ rats were exposed by inhalation to MEKO vapor /for 3 hours a day, 5 days a week for 4 weeks at doses of 25, 100, and 400 ppm. Exposure levels were analyzed and particle size distribution measured. Ten animals/sex/group were used. At 100 ppm increased methemoglobin was observed in female rats. At 400 ppm significant alterations in most hematological parameters (increased methemoglobin, increased reticulocytes, increased platelets, increased MCW and MCH, increased total leucocytes and erythrocytes and MCHC) were observed for both male and female rats. At 400 ppm remarkable erythrocyte morphology included increased numbers of nucleated erythrocytes and polychromia, were seen in male and female rats. At 400 ppm increased absolute and relative organ weights of liver and spleen in males and females were seen.

/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ /Fischer 344 rats were dosed once daily by gavage for 28 days at doses of 0, 250, 500 mg/kg/day. Control animals (15/group) received distilled water (negative control), 0.5% methylcellulose (vehicle control) or clofibric acid, 250 mg/kg (positive control), at the same dose volume as administered to the treated animals. Under the conditions of this study, MEKO did not produce any significant hepatic peroxisome proliferation in the rate, as indicated by a lack of effect on palmitoyl-CoA oxidation and by electron microscopy. The potential responsiveness of the animals used in this study was confirmed by the marked induction of palmitoyl-CoA in the rats treated with clofibric acid. While MEKO was not a peroxisome proliferator in the rat, significant increase in the levels of hepatic glutathione (primarily reduced glutathione) were observed in rats given 250 and 500 mg/kg/day MEKO for 14 days. This lack of an effect after 7 days of dosing correlated with the hepatocellular hypertrophy which was seen microscopically after 14 and 28 but not 7 days of treatment.

The rate constant for the vapor-phase reaction of 2-butanone oxime with photochemically-produced hydroxyl radicals has been estimated as 1.48X10-12 cu cm/molecule-sec at 25 °C(SRC) using a structure estimation method(1). This corresponds to an atmospheric half-life of about 11 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1).

According to the 2006 TSCA Inventory Update Reporting data, the number of persons reasonably likely to be exposed in the industrial manufacturing, processing, and use of 2-butanone oxime is 1000 or greater; the data may be greatly underestimated(1).

NIOSH (NOES Survey 1981-1983) has statistically estimated that 313,185 workers (25,609 of these were female) were potentially exposed to 2-butanone oxime in the US(1). Occupational exposure to 2-butanone oxime may occur through inhalation and dermal contact with this compound at workplaces where 2-butanone oxime is produced or used(SRC). The U.S. Consumer Product Safety Commission's Chemicals in Products database lists 764 products that contain 2-butanone oxime (methyl ethyl ketoxime); all but 16 of these products are in the paints and coatings category; other products containing methyl ethyl ketoxime included a glass cleaner and a skin soap(2). The general population will exposed to 2-butanone oxime through inhalation of vapors and dermal contact from consumer products containing the compound (especially paints and coatings)(SRC).

The mean concentration of 2-butanone oxime detected in three alkyd enamel paints purchased from retail outlet stores was 0.92, 2.93 and 1.34 mg/g respectively(1); in two-week chamber studies using these paints, an average of 84% of the 2-butanone oxime in the paints initially was recovered in the volatile emissions(1).

Pursuant to section 8(d) of TSCA, EPA promulgated a model Health and Safety Data Reporting Rule. The section 8(d) model rule requires manufacturers, importers, and processors of listed chemical substances and mixtures to submit to EPA copies and lists of unpublished health and safety studies. 2-Butanone, oxime is included on this list. Effective date: 12/15/86; Sunset date: 12/19/95.

All persons who manufacture (including import) or process or intend to manufacture or process MEKO, including persons who manufacture or process or intend to manufacture or process MEKO as a byproduct, or who import or intend to import products which contain MEKO, after the date specified in paragraph (e) of this section to the end of the reimbursement period, shall submit letters of intent to conduct testing, submit study plans, conduct tests and submit data, or submit exemption applications, as specified in this section, subpart A of this part, and parts 790 and 792 of this chapter for single-phase rulemaking.Methyl ethyl ketoxime is included on this list. Required testing: health effect testing.

Used as an anti-skinning agent in alkyd paints; Also used as a blocking agent (urethane polymers) and a corrosion inhibitor (boilers); [AIHA]

Painting (Pigments, Binders, and Biocides) [Category: Paint]

Antiskinning agent in lacquers.

2-Butanone oxime is widely used as a blocking agent in coatings such as isocyanate urethane coatings for wire and in magnetic tape coatings and resins

Catalyst, oxygen scavenger in steam generation, extraction of silver

Used primarily as an antiskinning agent in alkyd coating resins to prevent formation of a solid or gelatinous skin in the container.

2023: 2,500,000 - <4,000,000 lb

2-Butanone, oxime is listed as a High Production Volume (HPV) chemical (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).

Production volumes for non-confidential chemicals reported under the Inventory Update Rule.[Table#8032]

Production volume for non-confidential chemicals reported under the 2006 Inventory Update Rule. Chemical: 2-Butanone, oxime. Aggregated National Production Volume: 10 to < 50 million lbs.

Machinery Manufacturing

2-Butanone, oxime: ACTIVE

The U.S. Consumer Product Safety Commission's Chemicals in Products database lists 764 products that contain 2-butanone oxime (methyl ethyl ketoxime); all but 16 of these products are in the paints and coatings category; other products containing methyl ethyl ketoxime included a glass cleaner and a skin soap.