1,1Dichloroethane [factsheet]

1,1-DICHLOROETHANE

Please Note: The main source of information for this fact sheet is the Agency for Toxic Substances and Disease Registry's (ATSDR's) Toxicological Profile for 1,1-Dichloroethane. Other sources include the Hazardous Substances Data Bank (HSDB), a database of summaries of peer-reviewed literature, and the Registry of Toxic Effects of Chemical Substances (RTECS), a database of toxic effects that are not peer reviewed.

Environmental/Occupational Exposure

* 1,1-Dichloroethane has been detected in ambient air; average levels of 0.055 ppb have been reported in urban air in the United States. (1)

* Drinking water supplies have been found to contain 1,1-dichloroethane; levels up to 4.8 ppb have been detected. (1)

* Occupational exposure to 1,1-dichloroethane may occur for those workers in the rubber and plastic, chemical, electrical equipment and supply, medical and other health services, and oil and gas industries. (1)

Assessing Personal Exposure

* Tests are available that measure 1,1-dichloroethane in urine, blood, breath, and body tissues. (1)

Health Hazard Information

Acute Effects:

* Acute (short-term) inhalation exposure to high levels (105,000 mg/m³) of 1,1-dichloroethane in humans results in CNS depression and a cardiostimulatory effect, resulting in cardiac arrhythmias. (1)

* Acute dermal exposure to 1,1-dichloroethane in humans can cause skin burns, scaliness, or rashes. (2)

* Tests involving acute exposure of animals, such as the LC₅₀ and LD₅₀tests in rats and mice, have shown 1,1-dichloroethane to have low acute toxicity from inhalation exposure and moderate acute toxicity from oral exposure. (3)

Chronic Effects (Noncancer):

* No information is available on the chronic (long-term) effects of 1,1-dichloroethane in humans. (1)

* No adverse clinical effects have been noted in rats, rabbits, or guinea pigs exposed to 1,1-dichloroethane via inhalation, while studies in cats have noted effects on the kidneys. (1)

* The only adverse health effect noted in two oral animal studies was body weight depression. (1)

* The RfC and the RfD for 1,1-dichloroethane are under review by EPA. (4)

* EPA has calculated a provisional RfD of 0.1 mg/kg/d for 1,1-dichloroethane. (5)

Reproductive/Developmental Effects:

* No information is available on the reproductive or developmental effects of 1,1-dichloroethane in humans. (1)

* In the only available reproductive or developmental animal study, retarded fetal development (but no malformations) was observed from inhalation exposure to 1,1-dichloroethane. (1)

Cancer Risk:

* No information is available on the carcinogenic effects of 1,1-dichloroethane in humans. (1)

* No animal inhalation cancer studies are available on 1,1-dichloroethane, while an oral animal study reported a significantly positive dose-related trend in hemangiosarcomas, mammary tumors, liver tumors, and endometrial stromal polyps. However, only the incidence of endometrial stromal polyps was significantly increased over the controls. (1,4)

* EPA has classified 1,1-dichloroethane as a Group C, possible human carcinogen. (4)

Physical Properties

* 1,1-Dichloroethane is a colorless oily liquid which is very volatile. (1)

* 1,1-Dichloroethane has an odor similar to ether; the odor threshold is 120 ppm. (1)

* The chemical formula for 1,1-dichloroethane is C₂H₄Cl₂, and the molecular weight is 98.97 g/mol. (1)

* The vapor pressure for 1,1-dichloroethane is 230 mm Hg at 25 EC, and it has a log octanol/water partition coefficient (Log K_ow) of 1.79. (1)

Uses

* 1,1-Dichloroethane is primarily used as an intermediate in the manufacture of other products such as vinyl chloride, 1,1,1-trichloroethane, and high vacuum rubber. (1)

* 1,1,-Dichloroethane has limited use as a solvent for plastics, oils, and fats. (1)

* In the past, 1,1-dichloroethane was used as an anesthetic, but that use has been discontinued. (1)

Health Data from Inhalation Exposure

Concentration (mg/m³)	Health numbers^a	Regulatory, advisory numbers^b	Reference
1,000,000.0
_ _ _ _ 100,000.0
_ _ _ _ 10,000.0	* LC₅₀ (mice) (70,027 mg/m³) * LC₅₀ (rats) (64,765 mg/m³)		3 3
_ _ _ _ 1,000.0		* ACGIH STEL (1,010 mg/m³)	1
_ _ _ _ 100.0		* ACGIH TLV (TWA) (810 mg/m³) * OSHA PEL (TWA) (400 mg/m³)	1 1

ACGIH STELCAmerican Conference of Governmental and Industrial Hygienists' short-term exposure limit: 15-min time-weighted-average exposure that should not be exceeded at any time during a workday even if the 8-h time-weighted-average is within the threshold limit value.

ACGIH TLVCAmerican Conference of Governmental and Industrial Hygienists' threshold limit value expressed as a time-weighted average; the concentration of a substance to which most workers can be exposed without adverse effects.

LC₅₀ (Lethal Concentration₅₀)CA calculated concentration of a chemical in air to which exposure for a specific length of time is expected to cause death in 50% of a defined experimental animal population.

OSHA PELCOccupational Safety and Health Administration's permissible exposure limit expressed as a time-weighted average; the concentration of a substance to which most workers can be exposed without adverse effect averaged over a normal 8-h workday or a 40-h workweek.

^a Health numbers are toxicological numbers from animal testing or risk assessment values developed by EPA.

^b Regulatory numbers are values that have been incorporated in Government regulations, while advisory numbers are nonregulatory values provided by the Government or other groups as advice.

References

1. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for 1,1-Dichloroethane. U.S. Public Health Service, U.S. Department of Health and Human Services, Atlanta, GA. 1990.

2. U.S. Department of Health and Human Services. Hazardous Substances Data Bank (HSDB, online database). National Toxicology Information Program, National Library of Medicine, Bethesda, MD. 1993.

3. U.S. Department of Health and Human Services. Registry of Toxic Effects of Chemical Substances (RTECS, online database). National Toxicology Information Program, National Library of Medicine, Bethesda, MD. 1993.

4. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on 1,1-Dichloroethane. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1993.

5. U.S. Environmental Protection Agency. Health Effects Assessment Summary Tables. Annual Update. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1993.