1,2Dichloropropane [factsheet]

1,2-DICHLOROPROPANE

(PROPYLENE DICHLORIDE)

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 1,2-Dichloropropane. Other sources include EPA's Integrated Risk Information System (IRIS), which contains information on inhalation chronic toxicity of 1,2-dichloropropane and the RfC, and the Registry of Toxic Effects of Chemical Substances (RTECS), a database of toxic effects that are not peer reviewed.

Environmental/Occupational Exposure

* 1,2-Dichloropropane has been detected at low levels in ambient air, with an average level in air of about 0.022 ppb. (1)

* 1,2-Dichloropropane has been detected in a few drinking water supplies. A nationwide survey of groundwater supplies showed that 1.4 percent of these supplies contained 1,2-dichloropropane at levels around 1 ppb. (1,2)

* Occupational exposure to 1,2-dichloropropane may occur during its production, during its use in chemical reactions or as an industrial solvent, or from evaporation from wastewater that contains the chemical. (1)

Assessing Personal Exposure

* Medical tests can detect 1,2-dichloropropane in urine and blood. 1,2-Dichloropropane leaves the body quickly, and thus the tests should be done soon after the exposure. (1)

Health Hazard Information

Acute Effects:

* Acute (short-term) exposure to 1,2-dichloropropane in humans from inhalation and oral exposure results in effects on the gastrointestinal system, blood, liver, kidneys, and central nervous system. Additional effects noted in humans, from inhalation exposure only, are effects on the lung (chest discomfort, dyspnea [shortness of breath], and cough) and the eyes (conjunctival hemorrhages). (1)

* Animal studies have reported effects on the respiratory system, liver, kidneys, eyes, and central nervous system from acute inhalation exposure to 1,2-dichloropropane. (1)

* Tests involving acute exposure of animals, such as the LC₅₀and LD₅₀ tests in rats, have shown 1,2-dichloropropane to have moderate acute toxicity from inhalation and oral exposure. (1,3)

Chronic Effects (Noncancer):

* No information is available on the effects from chronic (long-term) exposure to 1,2-dichloropropane in humans from inhalation or oral exposure. (1)

* Chronic animal studies, via inhalation exposure, have reported effects on the respiratory system and blood, while oral animal studies have noted effects on the blood, liver, and central nervous system. (1,4)

* The RfC for 1,2-dichloropropane is 0.004 mg/m³ based on hyperplasia of the nasal mucosa in rats. (5)

* EPA has high confidence in the study on which the RfC was based because it used an adequate number of animals, exposure concentrations, and controls, examined three species, focused on known target organs, and the incidence and severity of the nasal lesions were exposure-related; medium confidence in the database because there are no chronic inhalation studies; and, consequently, medium confidence in the RfC. (5)

* EPA has not established an RfD for 1,2-dichloropropane. (5)

Reproductive/Developmental Effects:

* A case was reported of a woman who was hospitalized with metrorrhagia (bleeding from the uterus between menstrual periods) after acute inhalation exposure to 1,2-dichloropropane. No other information is available on the reproductive or developmental effects of 1,2-dichloropropane in humans. (1)

* No reproductive effects were noted in several animal inhalation studies. (1)

* Developmental effects, such as an increased incidence of delayed ossification of the bones of the skull, and reproductive effects such as testicular degeneration and increased incidences of infection of the ovary, uterus, or other organs, have been observed in animals exposed to 1,2-dichloropropane by gavage (experimentally placing the chemical in the stomach). It is not known if the infections observed were related to 1,2-dichloropropane treatment since controls were also infected. (1)

Cancer Risk:

* No studies are available regarding carcinogenic effects in humans from inhalation or oral exposure to 1,2-dichloropropane. (1)

* An increased incidence of mammary gland tumors in female rats and liver tumors in male and female mice were reported in studies in which 1,2-dichloropropane was given by gavage. (1,6)

* EPA has classified 1,2-dichloropropane as a Group B2, probable human carcinogen. (7)

* EPA's Office of Air Quality Planning and Standards, for a hazard ranking under Section 112(g) of the Clean Air Act Amendments, has ranked 1,2-dichloropropane in the nonthreshold category. The 1/ED₁₀ value is 0.36 per (mg/kg)/d and this would place it in the low category under Superfund's ranking for carcinogenic hazard. (7)

Physical Properties

* The chemical formula for 1,2-dichloropropane is C₃H₆Cl₂, and the molecular weight is 112.99 g/mol. (1)

* 1,2-Dichloropropane is a colorless liquid which evaporates quickly at room temperature. (1)

* 1,2-Dichloropropane has a chloroform-like odor and an odor threshold of 0.25 ppm. (1)

* The vapor pressure for 1,2-dichloropropane is 49.67 mm Hg at 25 EC, and it has a log octanol/water partition coefficient (log K_ow) of 1.99. (1)

Uses

* 1,2-Dichloropropane is used as a chemical intermediate in the production of chlorinated organic chemicals, as an industrial solvent, in ion exchange manufacture, in toluene diisocyanate production, in photographic film manufacture, for paper coating, and for petroleum catalyst regeneration. (1)

* 1,2-Dichloropropane was used in the past as a soil fumigant for a variety of crops. This use has been discontinued, and pesticide formulations containing 1,2-dichloropropane are no longer available in the United States. (1)

Health Data from Inhalation Exposure

Concentration (mg/m³)	Health numbers^a	Regulatory, advisory numbers^b	Reference
10,000.0
_ _ _ _ 1,000.0	* LC₅₀ (rats) (9,242 mg/m³)		1
_ _ _ _ 100.0		* OSHA PEL and ACGIH STEL (508 mg/m³) * OSHA PEL and ACGIH TLV (347 mg/m³)	6 6
_ _ _ _ 10.0
_ _ _ _ 1.0	* LOAEL (rats) (1.3 mg/m³)^c		5
_ _ _ _ 0.1
_ _ _ _ 0.01
_ _ _ _ 0.001	* RfC (0.004 mg/m³)		5

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.

LOAELCLowest-observed-adverse-effect level.

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.

RfCCReference concentration.

^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.

^c This LOAEL is from the critical study used as the basis for the EPA RfC.

References

1. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for 1,2-Dichloropropane (Draft). U.S. Public Health Service, U.S. Department of Health and Human Services. 1989.

2. U.S. Environmental Protection Agency. Health Advisory for 1,2-Dichloropropane. Office of Drinking Water, Washington, DC. 1987.

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

5. U.S. Environmental Protection Agency. Integrated Risk Information System (IRIS) on 1,2-Dichloropropane. Environmental Criteria and Assessment Office, Office of Health and Environmental Assessment, Office of Research and Development, Cincinnati, OH. 1993.

6. E.J. Calabrese and E.M. Kenyon. Air Toxics and Risk Assessment. Lewis Publishers, Chelsea, MI. 1991.

7. U.S. Environmental Protection Agency. Technical Background Document to Support Rulemaking Pursuant to the Clean Air ActCSection 112(g). Ranking of Pollutants with Respect to Hazard to Human Health. EPAB450/3-92-010. Emissions Standards Division, Office of Air Quality Planning and Standards, Research Triangle Park, NC. 1994.