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SECTION 1. CHEMICAL IDENTIFICATION

CHEMINFO Record Number: 775
CCOHS Chemical Name: Dibutyltin oxide

Synonyms:
DBTO
Dibutyloxide of tin
Dibutyloxostannane
Dibutyloxotin
Dibutylstannane oxide
Dibutylstannium oxide
Dibutyltin monoxide
Di-n-butyltin oxide

Chemical Name French: Oxyde de dibutylétain
Chemical Name Spanish: Dibutiloxoestannano
CAS Registry Number: 818-08-6
RTECS Number(s): WH7175000
EU EINECS/ELINCS Number: 212-449-1
Chemical Family: Tin and compounds / organometallic tin compound / dialkyltin oxide
Molecular Formula: C8-H18-O-Sn
Structural Formula: CH3-CH2-CH2-CH2-Sn(=O)-CH2-CH2-CH2-CH3

SECTION 2. DESCRIPTION

Appearance and Odour:
White powder (10,11,12)

Odour Threshold:
Not available

Warning Properties:
Information not available for evaluation

Uses and Occurrences:
Silicone catalyst; condensation catalyst; intermediate for other organotins.(12)


SECTION 3. HAZARDS IDENTIFICATION

EMERGENCY OVERVIEW:
White powder. Can burn if strongly heated. Can decompose at high temperatures forming tin and tin oxides. COMBUSTIBLE DUST. Can form explosive dust-air mixtures. TOXIC. Harmful if swallowed.



POTENTIAL HEALTH EFFECTS

Effects of Short-Term (Acute) Exposure

Inhalation:
Dibutyltin oxide (DBTO) is a dust which does not form a vapour. Short- term inhalation of high concentrations of dust may cause temporary irritation of the nose and throat and coughing. These are typical symptoms of dust exposure. Some organic tin compounds are known to cause neurological effects, such as headache, nausea and vomiting.(1) It is not known if exposure to high concentrations of DBTO would cause similar effects. There is no animal or human information available for DBTO.

Skin Contact:
DBTO dust is expected to produce no to mild irritation, based on animal and human information. A single application of DBTO (rubbed into the skin in powder form) on the back of the hands of volunteers was not irritating.(2) Some organic tin compounds can be absorbed through the skin. It is not known if DBTO can cause harmful effects by this route of exposure.

Eye Contact:
DBTO dust is expected to produce mild irritation and "foreign" body injury, based on animal and human information. Four workers were accidentally exposed to an unspecified amount of powdered DBTO. Slight pain, sensitivity to light, slight congestion and inflammation of the eye were observed. In all cases, treatment was not sought immediately after the incident and additional injury may have occurred. After treatment, the eyes healed within 3-20 days after exposure.(3)

Ingestion:
There is no human information available. Animal toxicity information and comparison to related organic tin compounds indicates that DBTO would be toxic by ingestion. Symptoms may include headache, listlessness, diarrhea and reduced appetite. Ingestion is not a typical route of occupational exposure.

Effects of Long-Term (Chronic) Exposure

There is no human information available for DBTO.

Nervous System:
Long-term exposure to related organic tin compounds has produced symptoms such as severe headaches.(1) It is not known if exposure to DBTO could cause similar effects.

Digestive System:
Long-term exposure to related organic tin compounds has produced gastrointestinal disturbances.(1) It is not known if exposure to DBTO could cause similar effects.

Carcinogenicity:

There is no animal or human information available for DBTO.

The International Agency for Research on Cancer (IARC) has not evaluated the carcinogenicity of this chemical.

The American Conference of Governmental Industrial Hygienists (ACGIH) has designated this chemical as not classifiable as a human carcinogen (A4).

The US National Toxicology Program (NTP) has not listed this chemical in its report on carcinogens.

Teratogenicity and Embryotoxicity:
There is no human information available. No conclusions can be drawn from one limited animal study. DBTO caused teratogenicity in rats following administration of an oral dose which did not produce maternal toxicity. This study is limited by the small number of animals studied, and the fact that only a single dose was administered on a single day.

Reproductive Toxicity:
There is no human or animal information available.

Mutagenicity:
There is no information available.

Toxicologically Synergistic Materials:
There is no information available.

Potential for Accumulation:
No specific information is available for DBTO. It probably does not accumulate in the body. The amount of an organotin compound absorbed into the body is related to its solubility in physiologic solutions.


SECTION 4. FIRST AID MEASURES

Inhalation:
If symptoms are experienced, remove source of contamination or have victim move to fresh air and obtain medical attention.

Skin Contact:
No health effects expected. If irritation does occur, flush with lukewarm, gently flowing water for 5 minutes or until the chemical is removed.

Eye Contact:
Do not allow victim to rub eye(s). Let the eye(s) water naturally for a few minutes. Have victim look right and left, and then up and down. If particle/dust does not dislodge, flush with lukewarm, gently flowing water for 5 minutes or until the particle/dust is removed, while holding the eyelid(s) open. If irritation persists, obtain medical attention. DO NOT attempt to manually remove anything stuck to the eye(s).

Ingestion:
NEVER give anything by mouth if the victim is rapidly losing consciousness, is unconscious or is convulsing. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz) of water to dilute material in the stomach. Obtain medical attention immediately.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest).
All first aid procedures should be periodically reviewed by a doctor familiar with the material and its conditions of use in the workplace.



SECTION 5. FIRE FIGHTING MEASURES

Flash Point:
Not applicable.

Lower Flammable (Explosive) Limit (LFL/LEL):
Not applicable

Upper Flammable (Explosive) Limit (UFL/UEL):
Not applicable

Autoignition (Ignition) Temperature:
279 deg C (534 deg F) (10,11)

Sensitivity to Mechanical Impact:
Not sensitive. Stable compound.

Combustion and Thermal Decomposition Products:
Tin and tin oxides.(10)

Flammable Properties:

Specific Hazards Arising from the Chemical:
During a fire, irritating/toxic tin oxides and tin fumes may be generated. Closed containers may explode in the heat of the fire.

Extinguishing Media:
Water spray, carbon dioxide, dry chemical powder, alcohol foam or polymer foam (10)

Fire Fighting Instructions:
Evacuate area and fight fire from a safe distance or a protected location. Approach fire from upwind to avoid toxic decomposition products.
Water or foam may cause frothing. The frothing may be violent and could endanger personnel close to the fire. However, a water spray or fog that is carefully applied to the surface of the burning material, preferably with a fine spray or fog nozzle, will cause frothing that will blanket and extinguish the fire. In addition, water spray or fog can be used to prevent dust formation, absorb heat, keep containers cool and protect exposed material. If a leak or spill has not ignited, use water spray to disperse the cloud of dust and protect personnel attempting to stop a leak. Water spray may be used to flush spills away from ignition sources. Solid streams of water may be ineffective and spread material.
The decomposition products of DBTO, such as tin and tin oxides, may be hazardous to health. Do not enter area without wearing specialized protective equipment suitable for the situation. Firefighters normal protective equipment, (Bunker Gear) will not provide adequate protection. Chemical resistant clothing (e.g. chemical splash suit) and positive pressure self-contained breathing apparatus (MSHA/NIOSH approved or equivalent) may be necessary.



NATIONAL FIRE PROTECTION ASSOCIATION (NFPA) HAZARD IDENTIFICATION

NFPA - Comments:
NFPA has no listing for this chemical in Codes 49 or 325.


SECTION 9. PHYSICAL AND CHEMICAL PROPERTIES

Molecular Weight: 248.95

Conversion Factor:
Not applicable

Physical State: Solid
Melting Point: Greater than 300 deg C (decomposes) (2,3)
Boiling Point: Not applicable
Relative Density (Specific Gravity): 1.6 (water = 1) (11)
Solubility in Water: Insoluble (9)
Solubility in Other Liquids: Not available
Coefficient of Oil/Water Distribution (Partition Coefficient): Not applicable
pH Value: Not applicable
Vapour Density: Not applicable
Vapour Pressure: Negligible at 20 deg C (2)
Saturation Vapour Concentration: Not available
Evaporation Rate: Negligible at 20 deg C (2)
Critical Temperature: Not applicable

SECTION 10. STABILITY AND REACTIVITY

Stability:
Normally stable

Hazardous Polymerization:
Does not occur

Incompatibility - Materials to Avoid:

NOTE: Chemical reactions that could result in a hazardous situation (e.g. generation of flammable or toxic chemicals, fire or detonation) are listed here. Many of these reactions can be done safely if specific control measures (e.g. cooling of the reaction) are in place. Although not intended to be complete, an overview of important reactions involving common chemicals is provided to assist in the development of safe work practices.


OXIDIZING AGENTS (e.g. perchlorates, permanganates, nitrates) - reaction may be violent. Risk of fire and explosion.(10,11)

Hazardous Decomposition Products:
None reported

Conditions to Avoid:
Generation of dust, static charge, sparks, flames, heat and other ignition sources.

Corrosivity to Metals:
Information not available


SECTION 11. TOXICOLOGICAL INFORMATION

LD50 (oral, male rat): 180 mg/kg (4); 520 mg/kg (5)
LD50 (oral, rat): 44.9 mg/kg (6, unverified)
LD50 (oral, rabbit): 150-500 mg/kg (7)

Eye Irritation:

Application of an unspecified amount of dibutyltin oxide (DBTO) dust produced slight irritation in rabbits. The eyes returned to normal in 2-3 days.(3) In an unconfirmed study, administration of 100 mg DBTO caused moderate irritation in a standard Draize test.(6)

Skin Irritation:

In one unconfirmed report, administration of 500 mg DBTO for 24 hours caused mild irritation in rabbits in a standard Draize test.(6)

Effects of Short-Term (Acute) Exposure:

Ingestion:
Listlessness and diarrhea, as well as reduced appetite, body weight, body temperature and urination were observed in male rabbits fed very high doses.(7)

Effects of Long-Term (Chronic) Exposure:

Ingestion:
Slight, reversible liver and kidney changes were observed in rats orally administered 2.5 mg/kg for 60 days. Daily administration of 100 mg/kg (number of days not specified) produced evident symptoms of poisoning (not described) in 2-3 days, with death on the 5th day. Autopsy showed severe degenerative changes in the liver and the kidneys. Daily doses (number of days not specified) of 25 mg/kg caused death within 11 days, with the same symptoms and almost identical pathological changes.(8) There are insufficient details available to evaluate this study. Significant toxicity was not observed in a small number of male rabbits orally administered 5 or 12 mg/kg/day for 3 weeks or 2 mg/kg/day for 10 weeks.(7)

Teratogenicity, Embryotoxicity and/or Fetotoxicity:
Teratogenicity has been observed in the absence of maternal toxicity in one limited study.
DBTO caused teratogenicity in rats at an oral dose that did not cause maternal toxicity. A single oral dose of approximately 20 mg/kg (cited as 80 microm/kg) in olive oil was administered to rats on the 8th day of pregnancy. No significant maternal toxicity was observed. Statistically significant teratogenicity (external malformations, skeletal malformations and skeletal variations) was observed.(9) This study is limited by the small number of animals (10/group) and the fact that only a single dose was administered on a single day.


SECTION 16. OTHER INFORMATION

Selected Bibliography:
(1) Tin, organic compounds. In: Documentation of the threshold limit values and biological exposure indices. 6th ed. American Conference of Governmental Industrial Hygienists, 1991. p. 1552-1560
(2) Lyle, W.H. Lesions of the skin in process workers caused by contact with butyl tin compounds. British Journal of Industrial Medicine. Vol. 15 (July 1958). p. 193-196
(3) Nemeto, T., et al. Keratitis superficialis believed to have been caused by vinyl chloride stabilizer. Rinsho Ganka (Clinical Ophthalmology). Vol. 11, no. 4 (1957). p. 613-616. (English translation: NIOSHTIC Control Number: 00103439)
(4) Mazaev, V., et al. Comparative hygienic toxicologic assessment of alkyl oxides. (English summary). Gigiena i Sanitariya. Vol. 4 (1977). p. 14-18 (In Russian)
(5) Klimmer, O.R. The use of organotin compounds from an experimental- toxicological point of view. (English summary). Arzneimittel-Forschung. Vol. 19 (1969). p. 934-939 (In German)
(6) RTECS record for stannane, dibutyloxo-. Last updated: 9607
(7) Sakunaga, K. Experimental studies on the toxicity of butyl tin compounds, especially dibutyl tin dilaurate, dibutyl tin monoxide, and tributyl tin monoxide through the digestive tract. Journal of the Tokyo Medical College. Vol. 19, no. 1 (1961). (English translation: NIOSHTIC Control Number: 00103120)
(8) Bartalini, E. Experimental study of the toxicity of a tin organic compound used as a plastifier. (Italian). Medicina del Lavoro. Vol. 50, no. 5 (1950). p. 338-350
(9) Noda, T. et al. Teratogenic effects of various di-n-butyltins with different anions and butyl(3-hydroxybutyl)tin dilaurate in rats. Toxicology. Vol. 85, nos. 2,3 (Dec. 31, 1993). p. 149-160
(10) The Sigma-Aldrich library of chemical safety data. Ed. II. Sigma-Aldrich Corporation, 1988. p. 1107D
(11) Chemical safety sheets. Kluwer Academic Publishers, 1991. p. 281
(12) Hawley's condensed chemical dictionary. 12th ed. Van Nostrand Reinhold, 1993. p. 375
(13) Field, P. Explosibility assessment of industrial powders and dusts. Building Research Establishment, 1983
(14) Grossel, S.S. Safety considerations in conveying of bulk solids and powders. Journal of Loss Prevention in the Process Industries. Vol. 1 (Apr. 1988). p. 62-74
(15) Schwab, R.F. Dusts. In: Fire protection handbook. Edited by A.E. Cote. 18th ed. National Fire Protection Association, 1991. p. 4-174 to 4-181
(16) Indus Bio-Test Labs Inc. Initial submission from Attochem Inc. to USEPA regarding toxicity studies of dibutyl tin oxide and stannous oxalate with cover letter dated 082192. Attochem North America Inc. Date produced: Aug. 21, 1992. EPA/OTS 88-920008457. NTIS/OTS057037.

Information on chemicals reviewed in the CHEMINFO database is drawn from a number of publicly available sources. A list of general references used to compile CHEMINFO records is available in the database Help.


Review/Preparation Date: 1997-03-26

Revision Indicators:
Toxicological info 2003-09-25
Teratogenicity/embryotoxicity 2003-09-25
WHMIS detailed classification 2003-09-25
WHMIS proposed classification 2003-09-25
WHMIS health effects 2003-09-25
WHMIS disclosure list 2003-09-25
Emergency overview 2003-09-25
Handling 2003-10-06
PEL-TWA transitional 2003-12-04
PEL transitional comments 2003-12-04
PEL-TWA final 2003-12-04
PEL final comments 2003-12-04
Bibliography 2006-04-25
LFL/LEL 2006-10-05
UFL/UEL 2006-10-05



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