Ethylene glycol is a federal hazardous air pollutant and was identified as a toxic air contaminant in April 1993 under AB 2728.
CAS Registry Number: 107-21-1
Molecular Formula: C2H6O2
Ethylene glycol is a colorless, odorless, sweet-tasting, viscous liquid that is hygroscopic. It is miscible with water, lower aliphatic alcohols, glycerol, acetic acid, acetone and similar ketones, aldehydes, pyridine, and similar coal tar bases. Ethylene glycol is slightly soluble in ether and practically insoluble in benzene and its homologs, chlorinated hydrocarbons, petroleum ether, and oils (Merck, 1989).
|Boiling Point||197.6 oC|
|Melting Point||-13.0 oC|
|Flash Point||115 oC (closed cup)|
|Vapor Density||2.14 (air = 1)|
|Density/Specific Gravity||1.1135 at 20 oC (water = 1)|
|Vapor Pressure:||0.06 mm Hg at 20 oC|
|Log Octanol/Water Partition Coefficient||-1.36|
|Conversion Factor||1 ppm = 2.54 mg/m3|
(HSDB, 1991; Merck, 1989; U.S. EPA, 1994a)
Ethylene glycol is used as an antifreeze, as a heat transfer agent, in polyester fiber and film manufacture, as a deicer, and as a solvent (HSDB, 1991).
The primary stationary sources that have reported emissions of ethylene glycol in California are commercial printing businesses, manufacturers of wood buildings and mobile homes, and funeral and crematorium services (ARB, 1997b).
Ethylene glycol was registered for use as a pesticide; however as of December 31, 1990, it is no longer registered for pesticidal use in California (DPR, 1997).
The total emissions of ethylene glycol from stationary sources in California are estimated to be at least 37,000 pounds per year, based on data reported under the Air Toxics "Hot Spots" Program (AB 2588) (ARB 1997b).
No information about the natural occurrence of ethylene glycol was found in the readily-available literature.
No Air Resources Board data exist for ambient measurements of ethylene glycol.
No information about the indoor sources and concentrations of ethylene glycol was found in the readily-available literature.
Ethylene glycol exists in the atmosphere in the gas phase. The dominant atmospheric loss process for ethylene glycol is by reaction with the OH radical. Based on this reaction, the atmospheric half-life and lifetime of ethylene glycol is estimated to be 1.3 days and 1.9 days, respectively (Atkinson, 1989). The major product of this reaction is expected to be hydroxyacetaldehyde (Atkinson, 1995).
For non-cancer health effects, ethylene glycol contributed to the total hazard index in 1 of the approximately 89 risk assessments reporting a total chronic hazard index greater than 1 (OEHHA, 1996b).
Possible routes of human exposure to ethylene glycol are inhalation, ingestion, and dermal contact.
Non-Cancer: Ethylene glycol is a central nervous system depressant in humans. It is metabolized to oxalic and other acids and may cause acidosis. Following ingestion of large quantities, acute symptoms include vomiting, drowsiness, coma, respiratory failure, and convulsions. Cardiopulmonary effects and renal injury may occur subsequently. No adverse effects were noted in one study of individuals chronically exposed by inhalation to low levels of ethylene glycol for approximately one month. However, short-term exposure of humans to high levels of ethylene glycol aerosol produced irritation (Wills et al., 1974). Rats, rabbits, and guinea pigs, subchronically exposed to ethylene glycol by inhalation developed ocular irritation and lesions and pulmonary inflammation (U.S. EPA, 1994a).
The United States Environmental Protection Agency (U.S. EPA) has not established a Reference Concentration (RfC) for ethylene glycol, but has set an oral Reference Dose (RfD) of 2.0 milligrams per kilogram per day based on kidney toxicity in rats. The U.S. EPA estimates that consumption of this dose or less, over a lifetime, would not likely result in the occurrence of chronic non-cancer effects (U.S. EPA, 1994a).
No information is available on adverse reproductive or developmental effects of ethylene glycol in humans. Rodents in several studies, exposed by gavage or inhalation, exhibited adverse effects on fetuses that included increased preimplantation loss, delayed ossification, and an increased incidence of fetal malformations (U.S. EPA, 1994a).
Cancer: No information is available on the carcinogenic effects of ethylene glycol in humans. The U.S. EPA has classified ethylene glycol in Group D: Not classifiable as to human carcinogenicity (U.S. EPA, 1994a). The International Agency for Research on Cancer has not classified ethylene glycol as to its human carcinogenicity (IARC, 1987a).