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CHEMINFO Record Number: 642
CCOHS Chemical Name: Iodoform

Formene triiode

Chemical Name French: Iodoforme
Chemical Name Spanish: Yodoformo
CAS Registry Number: 75-47-8
RTECS Number(s): PB7000000
EU EINECS/ELINCS Number: 200-874-5
Chemical Family: Halogenated aliphatic hydrocarbon / saturated halogenated hydrocarbon / halogenated alkane / halo alkane / trihalo alkane / haloform /iodo alkane / triiodo alkane
Molecular Formula: C-H-I3
Structural Formula: CHI3


Appearance and Odour:
Yellow to greenish-yellow powder or crystalline solid with a characteristic pungent odour.

Odour Threshold:
0.4 ppb (0.0062 mg/m3) (15); 5.0 ppb (8)

Warning Properties:
GOOD - TLV is more than 10 times the odour threshold.

Uses and Occurrences:
Sometimes used as a chemical intermediate. It was widely used medically as an antiseptic for external use because of its germicidal activity, but has now been largely replaced by other agents.


Yellow to greenish-yellow powder or crystalline solid with a pungent odour. Will not burn. Can decompose violently at high temperatures forming toxic gases such as hydrogen iodide, iodine and carbon monoxide. VERY TOXIC. May be fatal if inhaled, absorbed through the skin or swallowed. Central nervous system depressant. Vapour may cause headache, nausea, dizziness, drowsiness, incoordination, unconsciousness and death. Severe exposure may result in lung, kidney, liver and nervous system damage.


Effects of Short-Term (Acute) Exposure

Iodoform can be very toxic by inhalation. In animal studies it caused death at low concentrations (LC50 of 165 ppm).
Low concentrations of dust, mist or vapour may cause mild central nervous system (CNS) depression such as light-headedness, dizziness, nausea, inability to concentrate and reduced coordination.
Higher concentrations or repeated/prolonged exposures may cause serious effects on the nervous system, including delirium, hallucinations, coma, and death. Breathing difficulties and liver, kidney and heart damage may also occur.
No human information is available. These effects were observed in animal studies of iodoform and/or can be caused by the related chemical, chloroform.

Skin Contact:
There is no information available on the effect of iodoform on normal, intact human skin. Experiences with iodoform used as a medicinal agent show it may be absorbed through wounds and cause systemic toxicity (vomiting and CNS depression).

Eye Contact:
Dust, solid, mist or vapour may cause irritation. Irritation was observed in an animal study.

May be moderately toxic, based on animal information. No specific details are available, but may produce vomiting and symptoms similar to those described for inhalation. The lowest published toxic dose for humans is 114 mg/kg.(4)

Effects of Long-Term (Chronic) Exposure

VISUAL DISTURBANCES: Impaired vision has resulted from absorption of excessive amounts of iodoform applied to wounds or infections or from ingestion of large amounts. In rare cases, it has caused temporary blindness. Recovery is usually slow.(9)

Prolonged inhalation may cause CNS depression characterized by delirium, hallucinations, coma and death. Prolonged inhalation may also cause heart, liver and kidney damage.(2,3,4,5)

SKIN: Repeated contact may cause irritation and dermatitis.

SENSITIZATION: There is a report of a person developing an allergic skin reaction following treatment with a bismuth and iodoform paste. It is thought the person actually reacted to iodine released from the iodoform.(16)


Not carcinogenic in rats or mice following chronic oral dosing. No human information available.

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 not assigned a carcinogenicity designation to this chemical.

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

Teratogenicity and Embryotoxicity:
No information available

Reproductive Toxicity:
No information available

Positive results in short-term tests (bacteria and cultured mammalian cells). No animal or human information.

Toxicologically Synergistic Materials:
No information available

Potential for Accumulation:
Not expected to accumulate. Animal data indicates it is metabolized in part to carbon monoxide, which may cause an increase in carboxyhemoglobin. (7)


Remove source of contamination or move victim to fresh air. If breathing has stopped, trained personnel should begin artificial respiration (AR) or, if the heart has stopped, cardiopulmonary resuscitation (CPR) immediately. Avoid mouth-to-mouth contact. Immediately transport victim to an emergency care facility.

Skin Contact:
Quickly and gently blot or brush away excess chemical. Wash gently and thoroughly with water and non-abrasive soap for 20 minutes or until chemical is removed. Under running water, remove contaminated clothing, shoes and leather goods. If irritation persists, repeat flushing. If breathing has stopped, trained personnel should begin artificial respiration (AR) or, if the heart has stopped, cardiopulmonary resuscitation (CPR). Avoid mouth-to-mouth contact. Obtain medical attention immediately. Discard contaminated clothing, shoes and leather goods.

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 particle/dust is removed, while holding eyelid(s) open. If irritation persists, obtain medical attention. DO NOT attempt to manually remove anything stuck to eye(s).

Never give anything by mouth if victim is rapidly losing consciousness, is unconscious or convulsing. Have victim rinse mouth thoroughly with water. DO NOT INDUCE VOMITING. Have victim drink 240 to 300 mL (8 to 10 oz.) of water. If vomiting occurs naturally, rinse mouth and repeat administration of water. If breathing has stopped, trained personnel should begin artificial respiration (AR) or, if the heart has stopped, cardiopulmonary resuscitation (CPR) immediately. Avoid mouth-to-mouth contact. Quickly transport victim to an emergency care facility.

First Aid Comments:
Provide general supportive measures (comfort, warmth, rest).
Consult a doctor and/or the nearest Poison Control Centre for all exposures except minor instances of inhalation or skin contact.
All first aid procedures should be periodically reviewed by a doctor familiar with the material and its conditions of use in the workplace.


Flash Point:
Not combustible (does not burn)

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

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

Autoignition (Ignition) Temperature:
Not applicable

Sensitivity to Mechanical Impact:
Probably not sensitive. Stable under normal conditions.

Sensitivity to Static Charge:
Not applicable (does not burn).

Combustion and Thermal Decomposition Products:
Hydrogen iodide, iodine.(6,11)

Fire Hazard Summary:
During a fire, irritating/toxic gases and fumes such as hydrogen iodide, iodine and carbon monoxide may be generated. Iodoform decomposes violently at about 210 deg C. Container may explode in heat of fire.

Extinguishing Media:
Use extinguishing media appropriate for surrounding materials.

Fire Fighting Instructions:
Iodoform does not burn. If it can be done safely, move fire-exposed containers to a safe area. Use water spray to keep fire-exposed containers cool.
Do not enter without wearing specialized protective equipment suitable for the situation. Firefighter's normal protective clothing (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.


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


Molecular Weight: 393.72

Conversion Factor:
1 ppm = 16.1 mg/m3; 1 mg/m3 = 0.06 ppm at 25 deg C

Physical State: Solid
Melting Point: About 119 deg C (246 deg F)
Boiling Point: Decomposes violently at 210 deg C (410 deg F)
Relative Density (Specific Gravity): 4.1 (water = 1)
Solubility in Water: Practically insoluble (0.01 g/100 mL of water at 25 deg C) (3,6)
Solubility in Other Liquids: Soluble in ethyl alcohol, ether, benzene, acetone, chloroform, glycerol and carbon disulfide.
Coefficient of Oil/Water Distribution (Partition Coefficient): Not available
pH Value: Not available
Vapour Density: 13.6 (air = 1) (14)
Vapour Pressure: Not available
Saturation Vapour Concentration: Not available
Evaporation Rate: Not available
Critical Temperature: Not available


Stable under normal conditions. Decomposes slowly in light.(11)

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.

STRONG OXIDIZERS - reacts vigorously.

STRONG BASES - reacts vigorously.

KETONES - reacts vigorously and exothermally with acetone (and similar ketones) in presence of strong base.(10)

ALKALI METALS (e.g. lithium) - reacts violently.

METALS (e.g. silver) - incandescence (glowing with heat) occurs upon contact with finely divided metal.

METALLIC SALTS (e.g. silver nitrate, mercury fluoride, mercuric oxide) - reacts vigorously.

HEXAMETHYLENETETRAMINE - a 1:1 mixture exploded at 178 deg C.

Hazardous Decomposition Products:
No information available

Conditions to Avoid:
Light. Temperatures above 210 deg C.

Corrosivity to Metals:
No information available, but probably not corrosive.


LC50 (rat): 165 ppm (7-hr exposure, 48-hour observation) (1)
LD50 (oral, rat): 355 mg/kg (1)
LD50 (oral, mouse): 470 mg/kg (1); 810 mg/kg (14)
LD50 (oral, rabbit): 450 mg/kg (1)
LD50 (oral, guinea pig): 487 mg/kg (1)
LD50 (dermal, rat): 1184 mg/kg (1)

SHORT-TERM EXPOSURE: In inhalation studies, rats exposed for 7 hours to 130-270 ppm showed signs of eye irritation (closing their eyes) and breathing difficulties (rapid and shallow breathing). Death was caused by heart and lung failure (cardiopulmonary collapse).
Rats exposed for 7 hrs/day for 7 consecutive days to 1 or 14 ppm did not develop any significant signs of toxicity. Minor kidney changes were observed in all the rats in the 14 ppm exposure group.(2)
It has been reported that absorption of significant amounts of iodoform may cause central nervous system depression, as well as heart, liver and kidney injury. However, no further details are available.(3)

LONG-TERM EXPOSURE: Weight loss and death were reported in rats given oral doses of 56-562 mg/kg/day and in mice given oral doses of 100 or 178 mg/kg/day, for 5 days/week for 6 weeks. In the higher dose groups, there was very high mortality.(4)

MUTAGENICITY: Positive results were reported in short-term tests using bacteria and cultured mammalian cells.(1)

CARCINOGENICITY: There was no evidence of carcinogenic action following oral dosing 5 days/week for 78 weeks in rats (doses up to 142 mg/kg/day) and mice (doses up to 93 mg/kg/day).(4)


Selected Bibliography:
(1) RTECS record for methane, triiodo-. Date of last update 9109
(2) Tansy, M.F., et al. Subacute inhalation toxicity testing with iodoform vapor. Journal of Toxicology and Environmental Health. Vol. 8, nos. 1-2 (1981). p. 59-70
(3) Patty's industrial hygiene and toxicology. 3rd rev. ed. Vol. 2B. John Wiley & Sons, 1981. p. 3470-3472
(4) Bioassay of iodoform for possible carcinogenicity. (National Cancer Institute Carcinogenesis Technical Report Series No. 110). U.S. Department of Health, Education, and Welfare, 1978
(5) Gosselin, R.E., et al. Clinical toxicology of commercial products. 5th ed. Williams & Wilkins, 1984. p. II-387
(6) Documentation of the threshold limit values and biological exposure indices. 5th ed. ACGIH, 1986. p. 324
(7) Anders, M.W., et al. Metabolism of haloforms to carbon monoxide : II. In vivo studies. Drug Metabolism and Disposition. Vol. 6, no. 5 (Sept. 1978). p. 556-560
(8) Amoore, J.E., et al. Odor as an aid to chemical safety : odor thresholds compared with threshold limit values and volatilities for 214 industrial chemicals in air and water dilution. Journal of Applied Toxicology. Vol. 3, no. 6 (1983). p. 272-290
(9) Grant, W.M. Toxicology of the eye. 3rd ed. Charles C. Thomas, 1986. p. 524
(10) Bretherick, L. Bretherick's handbook of reactive chemical hazards. 4th ed. Butterworths, 1990. p. 134-135
(11) Compendium of safety data sheets for research and industrial chemicals. Part II. VCH Publishers, 1985. p. 1006-1007
(12) The Sigma-Aldrich library of chemical safety data. Edition II. Vol. 1. Sigma-Aldrich, 1988. p. 1999C
(13) Comprehensive catalog & guide - 1988. SKC, 1987. p. 52
(14) HSDB record for iodoform. Complete updated on 92/01/28
(15) Ruth, J.H. Odor thresholds and irritation levels of several chemical substances : a review. American Industrial Hygiene Association Journal. Vol. 47 (Mar. 1986). p. A-142, A-147
(16) Goh, C.L., et al. Contact allergy to iodoform and bismuth subnitrate. Short Communications. Vol. 16, no. 2 (1987). p. 109-110
(17) NIOSH pocket guide to chemical hazards. NIOSH, June 1994. p. 172-173

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: 1992-11-12

Revision Indicators:
TDG 1994-02-01
Trans PEL-TWA 1993-04-01
Fire fighting instructions 1995-01-01
Respiratory guidelines 1995-11-01
US Transport 1996-06-01
Sampling 1996-06-01
EU class 1996-06-01
Bibliography 1996-06-01
Resistance of materials 1998-05-01
First aid skin 2003-05-16
Personal hygiene 2003-05-26
Carcinogenicity 2003-06-16
PEL-TWA final 2003-10-30

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