Hazardous substance assessment - n-Butyl acetate

Acute Toxicity (Inhalation – Dust and Mist):

Does not meet criteria

LC₅₀ : 5,2 mg/L (rat)^{Footnote 3}.

The studies were performed to replicate an early result of 160 ppm (0.74 mg/L). The results, including the initial study, range from 160 ppm to 9,312 ppm (0.74-44 mg/L); however, LC₅₀ values within the concentration value range for classification were obtained in only two cases, and these studies were either inconclusive or were determined to have methodological issues^{Footnote 4Footnote 5}. The majority of studies have determined that the LC₅₀ for n-butyl acetate is above the concentration value range for classification.

The available data do not meet the classification criteria for Acute Toxicity (Inhalation – Dust and Mist).

Skin Corrosion / Irritation:

Does not meet criteria

In an Organization for Economic Co-operation and Development Test Guideline (OECD TG) 404 study with rabbits, irritation was found to be mild/insignificant, with mean erythema and edema scores of 0 at 24, 48, and 72 hour time points (based on study summary^{Footnote 1}).

A 4-hour application of 0.5 mL of test substance on 6 rabbits using the Draize scoring method resulted in no erythema, edema, or other irritation, with mean erythema and edema scores of 0 at 24, 48, and 72 hours and 7 and 10 days ^{Footnote 6}.

The available data do not meet the classification criteria for Skin Corrosion / Irritation.

Serious Eye Damage / Eye Irritation:

Does not meet criteria

In an OECD TG 405 study, 0.1 mL of undiluted test substance was applied to the eyes of 4 rabbits, with mean scores for corneal opacity, iritis, conjunctive redness, and chemosis of 0, 0, 1, and 0, respectively at time points 24, 48 and 72 hours^{Footnote 6Footnote 7}.

The available data do not meet the classification criteria for Serious Eye Damage / Eye Irritation.

Respiratory Sensitization:

No data available

Skin Sensitization:e

Does not meet criteria

Results were negative in a Magnusson-Kligman guinea pig maximization test (GPMT) and a Buehler test (OECD Guideline 406 study)^{Footnote 1}.

The available data do not meet the classification criteria for Skin Sensitization.

Germ Cell Mutagenicity:

Does not meet criteria

In Vivo: A bone marrow micronucleus test produced negative results ^{Footnote 8}.

In Vivo: Results were negative in an Ames test^{Footnote 1} and a chromosomal aberration test^{Footnote 9}.

The available data do not meet the classification criteria for Germ Cell Mutagenicity.

Carcinogenicity:

No data available

n-Butyl acetate has not been reviewed by the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP), or the American Conference of Governmental Industrial Hygienists (ACGIH).

Reproductive Toxicity:

Does not meet criteria

An inhalation study in rats exposed to the n-Butyl acetate showed no reproductive effects, but an increase in the incidence of fetal rib deformities was observed^{Footnote 10}. A second generation reproductive toxicity inhalation study in rats showed statistically significant decreases in F2 pup body weights and absolute testis weights^{Footnote 11}. Both studies show that, while there were exposure-related growth effects such as lower pup weights, there were no functional effects on reproduction or other histopathological effects in parents.

The available data do not meet the classification criteria for Reproductive Toxicity.

Specific Target Organ Toxicity – Single Exposure:

Does not meet criteria

Oral Route of Exposure: No data available

Dermal Route of Exposure: No data available

Inhalation Route of Exposure: An inhalation study in humans showed severe throat irritation with exposure to 300 ppm of n-Butyl acetate, with all test subjects complaining of discomfort ^{Footnote 12}. As this is a subjective human observation, it would require objective measurement of STOT-SE respiratory tract irritation for classification.

An acute inhalation study in rats showed dose-dependent narcotic effects and respiratory tract irritation; at 6,867 ppm, signs of toxicity included respiratory irritation, breathing abnormalities, ataxia, and narcosis ^{Footnote 6}. Another study indicated that concentrations of 1,500, 3,000, and 6,000 ppm reduce motor activity and response to stimulus during exposure. At 6,000 ppm, the severity of hypo activity was minor to moderate. At 3,000 ppm, the severity of hypo activity in female rats was minor, while male 3,000 ppm rats were characterized as having minimal hypo activity. Only minimal hypo activity was observed at 1,500 ppm. The no-observed effect level (NOEL) post exposure was determined to be 1,500 ppm ^{Footnote 9}. Although there are some signs of narcotic effects, these effects occur at concentrations above the cut-off of 20 mg/L (4,170 ppm) for a vapour.

The available data do not meet the classification criteria for Specific Target Organ Toxicity – Single Exposure.

Specific Target Organ Toxicity – Repeated Exposure:

Does not meet criteria

Oral Route of Exposure: No data available

Dermal Route of Exposure: No data available

Inhalation Route of Exposure: A 13 week study in rats revealed necrosis of the olfactory epithelium on necropsy but at a dose above the concentration value range for classification ^{Footnote 13}. A secondary 13 week inhalation study in rats showed no systemic organ-specific toxicity^{Footnote 14}. A 14 week inhalation study in rats for neurotoxicity showed no adverse effects^{Footnote 14}.

The available data do not meet the classification criteria for Specific Target Organ Toxicity – Repeated Exposure.

Aspiration Toxicity:

No data available

No human data are available. This substance is not a liquid hydrocarbon.

Biohazardous Infectious Materials:

Not applicable

n-Butyl acetate is not a microorganism, protein or nucleic acid.

Physical hazards

Explosives:

Not Evaluated*

* Explosives are excluded from the Hazardous Products Act and Regulations. Explosives are regulated under the Explosives Act. For more information, visit Natural Resources Canada.

Flammable Gases:

Not applicable

n-Butyl acetate is not a gas. The classification criteria for Flammable Gases do not apply to this substance.

Aerosols:

Not evaluated

Classification of a hazardous product in the Aerosols hazard class is product dependent.

Oxidizing Gases:

Not applicable

n-Butyl acetate is not a gas. The classification criteria for Oxidizing Gases do not apply to this substance.

Gases Under Pressure:

Not applicable

n-Butyl acetate is not a gas. The classification criteria for Gases Under Pressure do not apply to this substance.

Flammable Liquids:

Category 2

n-Butyl acetate is a liquid with a flash point of 22oC (closed cup) & a boiling point of 127oC ^{Footnote 15Footnote 16}.

The available data meet the classification criteria for Flammable Liquids – Category 2 [HPR 7.6.1 (2)].

Flammable Solids:

Not applicable

n-Butyl acetate is not a solid. The classification criteria for Flammable Solids do not apply to this substance.

Self-Reactive Substances and Mixtures:

Does not meet criteria

The chemical composition of n-Butyl acetate precludes the possibility of any self-reactive properties and its auto-ignition temperature was measured to be 415 °C at 1010 hPa, determined by the EU method A.15 (based on study summary^{Footnote 1}).

The available data do not meet the classification criteria for Self-Reactive Substances and Mixtures.

Pyrophoric Liquids:

Does not meet criteria

n-Butyl acetate is a liquid, but is not known to be pyrophoric despite its long and widespread use.

The available data do not meet the classification criteria for Pyrophoric Liquids.

Pyrophoric Solids:

Not applicable

n-Butyl acetate is not a solid. The classification criteria for Pyrophoric Solids do not apply to this substance.

Self-Reactive Substances and Mixtures:

Does not meet criteria

n-Butyl acetate has an auto-ignition temperature of 415 °C at 1010 hPa, determined by the EU method A.15 (based on study summary ^{Footnote 1}), which is well above the spontaneous ignition temperature for classification.

The available data do not meet the classification criteria for Self-Heating Substances and Mixtures.

Substances and Mixtures which, in Contact with Water, Emit Flammable Gases:

Not applicable

n-Butyl acetate is an ester that does not contain metals or metalloids and is, therefore, excluded from classification [HPR 7.12.1(1)].

Oxidizing Liquids:

Not applicable

Paragraph 7.13.1(1)(b) of the HPR excludes from classification any organic liquid that contains oxygen, fluorine or chlorine if those elements are chemically bonded only to carbon and hydrogen. n-Butyl acetate is an ester, composed only of chemically bonded carbon, oxygen and hydrogen.

Oxidizing Solids:

Not applicable

n-Butyl acetate is not a solid. The classification criteria for Oxidizing Solids do not apply to this substance.

Organic Peroxides:

Not applicable

n-Butyl acetate is not an organic peroxide. The classification criteria for Organic Peroxides do not apply to this substance.

Corrosive to Metals:

No data available

n-Butyl acetate is not known to be corrosive to metals. In view of this, no data have been developed to determine whether the substance meets the classification criteria for Corrosive to Metals.

Combustible Dusts:

Not applicable

n-Butyl acetate is not a solid. The classification criteria for Combustible Dusts do not apply to this substance.

Simple Asphyxiants:

Not applicable

n-Butyl acetate is not a gas. The classification criteria for Simple Asphyxiants do not apply to this substance.

Chemicals Under Pressure:

Not evaluated

Classification of a hazardous product in the Chemicals Under Pressure hazard class is product dependent.

Regulatory and other information

Regulatory information:

Hazardous substance assessments are prepared by Health Canada as educational and information resources. Under the HPA, suppliers of hazardous products must, upon the sale or importation of a hazardous product, provide a safety data sheet and label that meet the requirements set out in the HPR.

Other information:

The information and classifications contained in these hazardous substance assessments are based on publicly available sources, such as peer-reviewed literature or reports by international bodies. New information, including proprietary information, could have an impact on the classification of substances or hazardous products containing them. It is the responsibility of the supplier to ensure the accuracy, sufficiency, and reliability of their hazardous product classifications.

Last updated:

2024

Prepared by:

Workplace Hazardous Materials Bureau, Health Canada