Propylene Glycol

This chemical does not meet GHS hazard criteria for 98% (6762 of 6899) of all reports.

Not Classified

Reported as not meeting GHS hazard criteria by 6762 of 6899 companies (only 2% companies provided GHS information). For more detailed information, please visit ECHA C&L website.

Aggregated GHS information provided per 6899 reports by companies from 22 notifications to the ECHA C&L Inventory.

Reported as not meeting GHS hazard criteria per 6762 of 6899 reports by companies.

There are 17 notifications provided by 137 of 6899 reports by companies with hazard statement code(s).

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown. For more detailed information, please visit ECHA C&L website.

H336: May cause drowsiness or dizziness [Warning Specific target organ toxicity, single exposure; Narcotic effects]

H370: Causes damage to organs [Danger Specific target organ toxicity, single exposure]

H372: Causes damage to organs through prolonged or repeated exposure [Danger Specific target organ toxicity, repeated exposure]

P260, P261, P264, P270, P271, P304+P340, P308+P316, P319, P321, P403+P233, P405, and P501 (click each P-code to see the statement)

Fresh air, rest.

Remove contaminated clothes. Rinse skin with plenty of water or shower.

Rinse with plenty of water (remove contact lenses if easily possible).

Rinse mouth. Seek medical attention if you feel unwell.

EYES: First check the victim for contact lenses and remove if present. Flush victim's eyes with water or normal saline solution for 20 to 30 minutes while simultaneously calling a hospital or poison control center. Do not put any ointments, oils, or medication in the victim's eyes without specific instructions from a physician. IMMEDIATELY transport the victim after flushing eyes to a hospital even if no symptoms (such as redness or irritation) develop.

SKIN: IMMEDIATELY flood affected skin with water while removing and isolating all contaminated clothing. Gently wash all affected skin areas thoroughly with soap and water. If symptoms such as redness or irritation develop, IMMEDIATELY call a physician and be prepared to transport the victim to a hospital for treatment.

INHALATION: IMMEDIATELY leave the contaminated area; take deep breaths of fresh air. If symptoms (such as wheezing, coughing, shortness of breath, or burning in the mouth, throat, or chest) develop, call a physician and be prepared to transport the victim to a hospital. Provide proper respiratory protection to rescuers entering an unknown atmosphere. Whenever possible, Self-Contained Breathing Apparatus (SCBA) should be used; if not available, use a level of protection greater than or equal to that advised under Protective Clothing.

INGESTION: DO NOT INDUCE VOMITING. If the victim is conscious and not convulsing, give 1 or 2 glasses of water to dilute the chemical and IMMEDIATELY call a hospital or poison control center. Be prepared to transport the victim to a hospital if advised by a physician. If the victim is convulsing or unconscious, do not give anything by mouth, ensure that the victim's airway is open and lay the victim on his/her side with the head lower than the body. DO NOT INDUCE VOMITING. IMMEDIATELY transport the victim to a hospital. (NTP, 1992)

Fire Extinguishing Agents: Water fog, alcohol foam, carbon dioxide, dry chemical. (USCG, 1999)

Use water spray, powder, alcohol-resistant foam, carbon dioxide.

Water fog, alcohol foam, carbon dioxide, dry chemical.

In case of fire, keep drums, etc, cool by spraying water.

Vapor is heavier than air.

Absorb liquid in sand or inert absorbent. Then store and dispose of according to local regulations.

SRP: Wastewater from contaminant suppression, cleaning of protective clothing/equipment, or contaminated sites should be contained and evaluated for subject chemical or decomposition product concentrations. Concentrations shall be lower than applicable environmental discharge or disposal criteria. Alternatively, pretreatment and/or discharge to a permitted wastewater treatment facility is acceptable only after review by the governing authority and assurance that "pass through" violations will not occur. Due consideration shall be given to remediation worker exposure (inhalation, dermal and ingestion) as well as fate during treatment, transfer and disposal. If it is not practicable to manage the chemical in this fashion, it must be evaluated in accordance with EPA 40 CFR Part 261, specifically Subpart B, in order to determine the appropriate local, state and federal requirements for disposal.

Collect leaking and spilled liquid in sealable containers as far as possible. Wash away spilled liquid with plenty of water.

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.

SRP: Local exhaust ventilation should be applied wherever there is an incidence of point source emissions or dispersion of regulated contaminants in the work area. Ventilation control of the contaminant as close to its point of generation is both the most economical and safest method to minimize personnel exposure to airborne contaminants. Ensure that the local ventilation moves the contaminant away from the worker.

Above 99 °C use a closed system, ventilation.

Propylene glycol should be handled in a well-ventilated environment; eye protection is recommended.

SMALL SPILLS AND LEAKAGE: If you should spill this chemical, use absorbent paper to pick up all liquid spill material. Seal the absorbent paper, as well as any of your clothing which may be contaminated, in a vapor-tight plastic bag for eventual disposal. Wash any surfaces you may have contaminated with a soap and water solution. Do not reenter the contaminated area until the Safety Officer (or other responsible person) has verified that the area has been properly cleaned.

STORAGE PRECAUTIONS: You should protect this material from exposure to light and moisture. Keep it away from oxidizing materials and store it under refrigerated temperatures. (NTP, 1992)

Separated from strong oxidants and alkalis. Dry. Well closed. Ventilation along the floor.

Propylene glycol is hygroscopic and should be stored in a well-closed container, protected from light, in a cool, dry place.

Propylene glycol, dipropylene glycol, and tripropylene glycol are stable materials that require no special handling procedures. They are noncorrosive and can be transported or stored in stainless steel, aluminum, and lined steel containers. Carbon steel is also acceptable, although slight iron contamination may occur upon extended periods of storage. U.S.P.-grade propylene glycol is typically stored in stainless steel.

30 [mg/m3]

1300 [mg/m3]

7900 [mg/m3]

Workplace Environmental Exposure Level (WEEL): 8-hr Time-weighted Average (TWA) 10vmg/cu m.

No indication can be given whether a harmful concentration in the air will be reached.

The substance is mildly irritating to the eyes and respiratory tract. Ingestion of large amounts could cause metabolic acidosis.

Residues of propylene glycol are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to growing crops or to raw agricultural commodities after harvest. Use: solvent, cosolvent.

Residues of propylene glycol are exempted from the requirement of a tolerance when used in accordance with good agricultural practice as inert (or occasionally active) ingredients in pesticide formulations applied to animals. Use: solvent, cosolvent.

Goggles. (USCG, 1999)

Protective gloves, safety spectacles.

NO open flames.

Avoid inhalation of mist and vapour. Use ventilation.

Protective gloves.

Wear safety spectacles.

Do not eat, drink, or smoke during work.

Thick odorless colorless liquid. Mixes with water. (USCG, 1999)

Large Crystals; CBI; Liquid; Wet Solid; Other Solid; Liquid; Liquid; Other Solid

Clear, colourless, hygroscopic, viscous liquid

Clear, colorless, viscous liquid; [ChemIDplus]

COLOURLESS ODOURLESS HYGROSCOPIC VISCOUS LIQUID.

Thick odorless colorless liquid.

Colorless viscous liquid

Practically odorless

Practically tasteless

370.8 °F at 760 mmHg (NTP, 1992)

187.6 °C

188.2 °C

370.8 °F

187.6 °C @760 [mm Hg]

-76 °F (NTP, 1992)

210 °F (NTP, 1992)

104 °C Pensky-Martens closed cup

210 °F (99 °C) (Closed cup)

225 °F (Open cup)

101 °C c.c.

greater than or equal to 100 mg/mL at 70 °F (NTP, 1992)

Soluble in water, ethanol and acetone

Soluble in benzene

Miscible with acetone and chloroform; soluble in ether. Will dissolve many essential oils, but is immiscible with fixed oils.

In water, 1X10+6 mg/L at 20 °C /miscible/

Solubility in water: miscible

1.04 at 68 °F (USCG, 1999) - Denser than water; will sink

1.0361 g/cu cm at 20 °C

Relative density (water = 1): 1.04

1.0361 @ 20°C

2.62 (NTP, 1992) - Heavier than air; will sink (Relative to Air)

Relative vapor density (air = 1): 2.6

0.08 mmHg at 68 °F ; 0.13 mmHg at 77 °F (NTP, 1992)

0.13 [mmHg]

0.13 mm Hg at 25 °C /Extrapolated/

Vapor pressure, Pa at 20 °C: 10.6

0.08 mmHg

log Kow = -0.92

At cool temperatures, propylene glycol is stable in a well-closed container, but at high temperatures, in the open, it tends to oxidize, giving rise to products such as propionaldehyde, lactic acid, pyruvic acid, and acetic acid. Propylene glycol is chemically stable when mixed with ethanol (95%), glycerin, or water; aqueous solutions may be sterilized by autoclaving.

700 °F (USCG, 1999)

Water soluble.

Alcohols and Polyols

PROPYLENE GLYCOL is hygroscopic. It is sensitive to excessive heat (tends to oxidize at high temperatures). This compound can react with oxidizing materials. It is incompatible with acid chlorides, acid anhydrides, chloroformates, and reducing agents. It dissolves many essential oils. A mixture of this compound with hydrofluoric acid and silver nitrate was put in a glass bottle which burst 30 minutes later. (NTP, 1992)

Reacts with strong oxidants, causing fire hazard.

Propylene glycol is incompatible with oxidizing reagents such as potassium permanganate.

No significantly dangerous substances are produced after contact with light, humidity or commonly available chemicals. Propylene glycol may react with hydrofluoric acid + nitric acid + silver nitrate to form the explosive silver fulminate.

A chemical polishing mixture /of hydrofluoric acid, propylene glycol, and silver nitrate/ was put into a closed glass bottle which burst 30 min later, and formation of silver fulminate was suggested. However, in absence of the silver salt such mixtures evolve gas and should not be stored in any event, especially after use for metal polishing, when the dissolved metal(s) tend to further destabilize the mixture.

CDC-ATSDR Toxicological Profile

The CIR Expert Panel concluded that ... PG and any PG >= 3 are safe as cosmetic ingredients in present practices of use and concentration as described in this safety assessment when formulated to be nonirritating.

Safe for use in cosmetics, with qualifications

EXPOSURE. Propylene glycol (PG) production capacity in the US was 1312 million pounds (596 kilotons) in 1998. Domestic demand was 1050 million pounds (477 kilotons). PG is used as an ingredient in cosmetics at concentrations of <0.1% to >50%. Approximately 4000 cosmetic products contained PG in 1994. Uses of PG, with percent of demand, are: unsaturated polyester resins, 26 percent; antifreeze and de- icing fluids, 22 percent; food, drug and cosmetics uses, 18 percent; liquid detergents, 11 percent; functional fluids (inks, specialty anti-freeze, de-icing lubricants), 4 percent; pet foods, 3 percent; paints and coatings, 5 percent; tobacco, 3 percent; miscellaneous, including plasticizer use, 8 percent. HEALTH. Propylene glycol (PG) is not acutely toxic. The lowest oral LD50 values range between 18 and 23.9 mg/kg (5 different species) and the reported dermal LD50 is 20.8 mg/kg. PG is essentially nonirritating to the skin and mildly irritating to the eyes. Numerous studies support that PG is not a skin sensitizer. Repeated exposures of rats to propylene glycol in drinking water or feed did not result in adverse effects at levels up to 10% in water (estimated at about 10 g/kg bw/day) or 5% in feed (dosage reported as 2.5 g/kg bw/day) for periods up to 2 years. In cats, two studies of at least 90 days duration show that a species-specific effect of increased Heinz bodies was observed (NOAEL = 80 mg/kg bw/day; LOAEL = 443 mg/kg bw/day), with other hematological effects (decrease in number of erythrocytes and erythrocyte survival) reported at higher doses (6-12% in diet, or 3.7-10.1 g/cat/day). Propylene glycol did not cause fetal or developmental toxicity in rats, mice, rabbits, or hamsters (NOAELs range from 1.2 to 1.6 g/kg bw/day in four species). No reproductive effects were found when propylene glycol was administered at up to 5% in the drinking water (reported as 10.1 g/kg bw/day) of mice. Propylene glycol was not a genetic toxicant as demonstrated by a battery of in vivo (micronucleus, dominant lethal, chromosome aberration) and in vitro (bacterial and mammalian cells and cultures) studies. No increase in tumors was found in all tissues examined when propylene glycol was administered in the diet of rats (2.5 g/kg bw/day for 2 years), or applied to the skin of female rats (100% PG; total dose not reported; 14 months) or mice (mouse dose estimated at about 2 g/kg bw/week; lifetime). These data support a lack of carcinogenicity for PG. ENVIRONMENT. ... Measured freshwater aquatic toxicity data for fish, daphnia and algae report LC/EC50 values of >18,000 mg/L. Therefore, PG is not acutely toxic to aquatic organisms except at very high concentrations. Using an assessment factor of 100 and the Ceriodaphnia data (48- hour EC 50 = 18,340 mg/l), the predicted no effect concentration is 183 mg/L.

Propylene glycol

No indication of carcinogenicity to humans (not listed by IARC).

Dry throat. Cough.

Dryness of eyes. Pain. Itching.

See Effects of short-term exposure

Respiratory (From the Nose to the Lungs)

Chemical: PROPYLENE GLYCOL

Neurotoxin - Acute solvent syndrome

Skin Sensitizer - An agent that can induce an allergic reaction in the skin.

JECFA: ADI: 0 to 25 mg/kg bw

Propylene Glycol

2 x 10^1 mg/kg-day

PDF Document

Not likely to be carcinogenic to humans

PPRTV Archive

ATSDR Final

PPRTV Current

LD50 Rat oral 21000 - 33700 mg/kg

LD50 Rat oral 22,000 mg/kg

LD50 Rat ip 6660 mg/kg

LD50 Rat iv 6423 mg/kg

For more Non-Human Toxicity Values (Complete) data for Propylene glycol (20 total), please visit the HSDB record page.

The effects of propylene-glycol (PG) alone and the interactions between PG and calcium channel blockers were investigated on the inward calcium current at motor nerve terminals in mice. Phrenic nerve/diaphragm preparations from male ICR-mice were used. Examining the effect of 5% PG on the potassium current at the nerve terminal showed two positive spikes generated by treatment with d-tubocurarine (d-Tc) at the terminal part of the nerve terminal. The second positive spike is ascribed to the outward potassium current. PG did not change this spike at all, suggesting that this compound had no effect on the potassium channels. Pretreatments with d-Tc, tetraethylammonium (TEA), and 3,4-diaminopyridine (DAP) evoked the prolonged negative component of the action potential at the terminal part of the nerve terminal. PG augmented this component which is ascribed to the inward calcium current. The effects of calcium channel blockers were examined to determine whether the calcium channel blockers antagonize PG. Cumulative addition of cadmium-chloride, manganese-chloride, or cobalt-chloride suppressed the prolonged negative component that had been augmented by treatment with PG.

Check the anion gap, arterial pH, renal function, and glucose level. Serum propylene glycol levels up to 1,000 mg/dL do not correlate well with clinical status. Patients have been conscious with serum levels of 760 mg/dL.

Maintain an open airway and assist ventilation if necessary. Administer supplemental oxygen. Treat coma, convulsions, cardiac arrhythmias, and metabolic acidosis if they occur. Observe the patient for several hours to monitor for for development of metabolic acidosis, especially if the patient is symptomatic or there is known co-ingestion of ethanol. Treat hypocalcemia with intravenous calcium gluconate or calcium chloride

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Ethylene glycol, glycols, and related compounds/

Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Do not use emetics. For ingestion, rinse mouth and administer 5 ml/kg up to 200 ml of water for dilution if the patient can swallow, has a strong gag reflex, and does not drool. Administer activated charcoal ... . /Ethylene glycol, glycols, and related compounds/

Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive-pressure ventilation techniques with a bag-valve-mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Treat seizures with diazepam or lorazepam ... . Use proparacaine hydrochloride to assist eye irrigation ... . /Ethylene glycol, glycols, and related compounds/

/HUMAN EXPOSURE STUDIES/ Results from human patch testing show no sensitization potential after semi-occlusive or occlusive epicutaneous application to the skin of volunteers (in excess of 300 subjects in total). These studies demonstrate that it is not irritating to skin or eye, nor does it cause sensitization by skin contact.

/HUMAN EXPOSURE STUDIES/ Patch-test in humans, 15 uL 100% propylene glycol/test chamber for 48 hr. Results: not irritating.

/HUMAN EXPOSURE STUDIES/ In 6 human volunteers, pads containing /propylene glycol/ test substance were fixed to the forearm for 2 hr, observation time: 7 days. Results: not irritating.

/HUMAN EXPOSURE STUDIES/ Cream containing 12% propylene glycol was tested on 204 persons. Results: not sensitizing.

For more Human Toxicity Excerpts (Complete) data for Propylene glycol (45 total), please visit the HSDB record page.

/LABORATORY ANIMALS: Acute Exposure/ Acute oral toxicity studies yielded similar, low acute toxicities with relatively high LD50 values ranging from 8000-46000 mg/kg/day propylene glycol for rodents and 18000-20000 mg/kg/day for both rabbits and guinea pigs. Clinical signs (loss of balance, marked depression, and analgesia) were reported in the rabbit and guinea pig only at extremely high doses that exceeded the established limit dose (5000 mg/kg) for an acute oral toxicity study. Similar effects were also evident in one study with mice only at doses that resulted in lethality (LD50 value of 24800 mg/kg/day).

/LABORATORY ANIMALS: Acute Exposure/ Propylene glycol induced degeneration of goblet cells (+69%) in tracheal lining of rabbits after 20 and 120 minutes of aerosol exposure to 10% aerosol in an acute inhalation toxicity study; no other toxicological effects were observed.

/LABORATORY ANIMALS: Acute Exposure/ In primary eye irritation studies, propylene glycol was instilled in the eyes of rabbits (0.1-0.5 mL). There were no treatment-related effects on the corneas of the animals and propylene glycol was classified as a non-irritant.

EC50; Species: Selenastrum capricornutum (green algae); Concentration: 19,000 mg/L for 96 hr; Effect: 14-day growth rate /Conditions of bioassay not specified/

EC50; Species: Selenastrum capricornutum (green algae); Concentration: 18,100 mg/L for 14 days; Effect: 14-day growth rate /Conditions of bioassay not specified/

EC50; Species: Daphnia magna (Water flea, age 6-24 hr); Conditions: freshwater, static, 20 °C, pH > or =7.0; Concentration: >10000000 ug/L for 24, 48 hr; Effect: intoxication, immobilization /formulation/

LC50; Species: Daphnia magna (water flea); Conditions: static; Concentration: 43,500 mg/L for 48 hr

For more Ecotoxicity Values (Complete) data for Propylene glycol (23 total), please visit the HSDB record page.

/BIRDS and MAMMALS/ Due to the low likelihood of exposure and low toxicity of propylene glycol ..., the /Environmental Protection/ Agency expects no effects to listed species or critical habitats and therefore makes a "No Effect" determination for this chemical.

/AQUATIC SPECIES/ The very low toxicity of propylene glycol to aquatic organisms, as indicated by the high LC50 values ..., further supports the unlikelihood of adverse effects to fish and aquatic invertebrates.

/AQUATIC SPECIES/ ...This research investigated the contributions of environmentally significant concentrations of selected /aircraft deicing fluid/ (ADF) components to the toxicity of ADF-containing waste streams, and to the inhibition of biodegradation of propylene glycol (PG), the most important component of ADF. The component chemicals studied were PG, the corrosion inhibitor 4(5)-methylbenzotriazole (MeBT; common name: tolyltriazole), and proprietary mixes of corrosion inhibitors, buffers, and surfactants referred to as the additive package or AdPack. Relative to PG alone, the different additives increased the toxicity of ADF and decreased PG biodegradation rates. In enrichments of soil microorganisms acclimated to ADF, the MeBT component significantly decreased cell growth rates and yields, and inhibited PG biodegradation to a greater extent than the AdPack. Microtox tests indicated that MeBT is the ADF component most toxic to microorganisms. However, acute aquatic toxicity tests indicated that the AdPack components were more toxic than MeBT to Ceriodaphnia dubia and Pimephales promelas, although both components were more toxic than PG alone. /Aircraft deicing fluid/

/AQUATIC SPECIES/ Streams receiving runoff from General Mitchell International Airport (GMIA), Milwaukee, Wisconsin, USA, were studied to assess toxic impacts of aircraft and runway deicers. Elevated levels of constituents related to deicing (propylene glycol, ethylene glycol, and ammonia) were observed in stream samples. The LC50s of type I deicer for Ceriodaphnia dubia, Pimephelas promelas, Hyalela azteca, and Chironimus tentans and the EC50 for Microtox were less than 5,000 mg/L of propylene glycol. Concentrations up to 39,000 mg/L were observed at airport outfall sites in samples collected during deicing events. The IC25s of type I deicer for C. dubia and P. promelas were less than 1,500 mg/L of propylene glycol. Concentrations up to 960 mg/L were observed in low-flow samples at an airport outfall site. Measured toxicity of stream water was greatest during winter storms when deicers were applied. Chronic toxicity was observed at airport outfall samples from low-flow periods in the winter and the summer, with the greater toxic impacts from the winter sample. All forms of toxicity in stream-water samples decreased as downstream flows increased. /Aircraft and runway deicers/

/AQUATIC SPECIES/ ... Many of the /aircraft/ deicers are formulated mixtures of ethylene glycol (EG) or propylene glycol (PG) and a variety of additives. Because these deicers may be intentionally or accidentally released into aquatic ecosystems, the possibility exists for direct and indirect adverse effects on aquatic organisms. Laboratory studies evaluated the comparative toxicity of formulated glycol deicers and pure materials on the water flea, Ceriodaphnia dubia, and fathead minnow, Pimephales promelas. Acute (48 hr and 96 hr) and short-term chronic tests were performed according to USEPA guidelines. The formulated mixtures were found to be substantially more toxic than either of the pure glycol materials. The 48 hr LC50s for C. dubia were 13,140 mg/L and 1,020 mg/L using formulated EG and PG, and 34,400 mg/L and 18,340 mg/L using pure EG and PG, respectively. The 96 hr LC50s for P. promelas were 8,050 mg/L and 710 mg/L using formulated EG and PG, and 72,860 mg/L and 55,770 mg/L using pure EG and PG, respectively. Chronic IC25s for C. dubia were 3,960 mg/L and 640 mg/L using formulated EG and PG, 12,310 mg/L and 13,470 mg/L using pure EG and PG. Chronic IC25s for P. promelas were 3,660 mg/L and 110 mg/L using formulated EG and PG, 22,520 mg/L and 6,940 mg/L using pure EG and PG. For airports that have stormwater discharge permits, numerical limits for EG and PG are generally listed, potential toxicity is assumed to be due to the glycol materials. However, other compounds in the mixtures may either contribute substantially to, or in some cases overshadow, the toxicity of the glycol materials.

1.30e+06

1.60e+07

4.00e+05

2.00e-01

8.10e+01

2.00e+01

Volatile

3.80e+06

4.90e+07

1.20e+06

Propylene glycol's production and use as an antifreeze in breweries and dairy establishments, substitute for ethylene glycol and glycerol, in the manufacture of synthetic resins, emulsifier in foods, solvent for food colors and flavors, and pharmaceutic aid (humectant, solvent) may result in its release to the environment through various waste streams. Its use to create artificial smoke and mist for theatrical use, as an airplane de-icing fluid and in aerosol mists that are commonly used in hospitals and public buildings for disinfection purposes will result in its direct release to the environment. If released to air, a vapor pressure of 0.13 mm Hg at 25 °C indicates propylene glycol will exist solely as a vapor in the ambient atmosphere. Vapor-phase propylene glycol will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 32 hours. Propylene glycol does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight. If released to soil, propylene glycol is expected to have very high mobility based upon an estimated Koc of 1. Volatilization from moist soil surfaces is not expected to be an important fate process based upon an estimated Henry's Law constant of 1.3X10-8 atm-cu m/mole. Propylene glycol is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Propylene glycol was mineralized 73-78% in laboratory studies conducted using an agricultural soil over a 51 day incubation period, suggesting biodegradation will be an important environmental fate process in soil. If released into water, propylene glycol is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Volatilization from water surfaces is not expected to be an important fate process based upon this compound's estimated Henry's Law constant. Numerous screening studies using wastewater or sewage inoculum as seed suggest that propylene glycol will be degraded readily in aqueous environments. An estimated BCF of 3 suggests the potential for bioconcentration in aquatic organisms is low. Propylene glycol is not expected to undergo hydrolysis since this compound lacks functional groups that hydrolyze under environmental conditions. Occupational exposure to propylene glycol may occur through inhalation and dermal contact with this compound at workplaces where propylene glycol is produced or used. Monitoring and use data indicate that the general population may be exposed to propylene glycol via inhalation and dermal contact with consumer products containing propylene glycol. (SRC)

Propylene glycol's production and use as an antifreeze in breweries and dairy establishments, substitute for ethylene glycol and glycerol, in the manufacture of synthetic resins, emulsifier in foods, solvent for food colors and flavors, and pharmaceutic aid (humectant, solvent)(1) may result in its release to the environment through various waste streams(SRC). Its use to create artificial smoke and mist for theatrical use, as an airplane de-icing fluid(1) and in aerosol mists that are commonly used in hospitals and public buildings for disinfection purposes(2) will result in its direct release to the environment(SRC).

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a log Kow of -0.92(2) and a regression-derived equation(3), indicates that propylene glycol is expected to have very high mobility in soil(SRC). Volatilization of propylene glycol from moist soil surfaces is not expected to be an important fate process(SRC) given an estimated Henry's Law constant of 1.3X10-8 atm-cu m/mole(SRC), derived from its vapor pressure, 0.13 mm Hg(4), and assigned value for water solubility of 1X10+6 mg/L (miscible)(5). Propylene glycol is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(4). Laboratory experiments using agricultural soils from South Carolina conducted at 22 °C and a fortification of 1,000 ppm propylene glycol, yielded 73-78% mineralization during a 51 day incubation period(6), suggesting that biodegradation will be an important fate process in soils(SRC).

AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 1(SRC), determined from a log Kow of -0.92(2) and a regression-derived equation(3), indicates that propylene glycol is not expected to adsorb to suspended solids and sediment(SRC). Volatilization from water surfaces is not expected(3) based upon an estimated Henry's Law constant of 1.3X10-8 atm-cu m/mole(SRC), derived from its vapor pressure, 0.13 mm Hg(5), and assigned value for water solubility of 1X10+6 mg/L (miscible)(6). According to a classification scheme(7), an estimated BCF of 3(SRC), from its log Kow(2) and a regression-derived equation(8), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Numerous screening studies using wastewater or sewage inoculum as seed, suggests that propylene glycol will be degraded readily under aqueous environments(9-11).

ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), propylene glycol, which has a vapor pressure of 0.13 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase propylene glycol is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 32 hours(SRC), calculated from its rate constant of 1.2X10-11 cu cm/molecule-sec at 25 °C(3). Propylene glycol does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(4).

AEROBIC: Propylene glycol achieved 64% of its theoretical BOD using a sewage inoculum and a 5 day incubation period(1). A Warburg respirometer study employing a sewage seed showed that propylene glycol reached 78% of its theoretical BOD during a 40 day incubation period(2). Propylene glycol achieved 2.2, 56.7 and 80% of its theoretical BOD using a sewage inoculum and 5, 10, and 50 day incubation periods, respectively(3). Using raw wastewater and synthetic seawater as inoculum, propylene glycol achieved 55 and 83% of its theoretical BOD during 5 and 20 day incubation periods, respectively(4). Using wastewater from pretreated domestic sewage, propylene glycol reached 74.5% of its theoretical BOD in 5 days(5). Propylene glycol underwent 73-78% mineralization within 51 days when incubated with various agricultural soils from Clemson University, SC under laboratory conditions at 22 °C and 1,000 ppm propylene glycol in the soil; 40-79% mineralization was observed for propylene glycol incubated in the same soils for 64 days at 7 °C(6).

AEROBIC: Propylene glycol is mineralized to CO2 in soil microcosms incubated at temperatures ranging from -2 to 25 °C. No lag time period was observed. Degradation occurred with propylene glycol alone and in combination with ethylene glycol and diethylene glycol at glycol concentrations ranging from 392 to 5278 mg/kg suggesting that high levels of glycols in deicing fluids are unlikely to inhibit biodegradation. Complete disappearance of 0.045% propylene glycol occurred after 12 days at 8 °C and 57% of the theoretical oxygen demand was recovered after 34 days. With 0.45% propylene glycol, 76% degradation and 44% mineralization was obtained after 111 days(1). The rate of biodegradation ranged from 11.4 to 41.4 mg/kg soil per day at 8 °C with an average of 22.7 mg/kg per day. Rates at 25 °C were approximately 3.4 times faster than those at 8 °C, ranging from 78.9 to 88 mg/kg per day with a mean of 83.5 mg/kg per day. At -2 °C, biodegradation rates for propylene glycol ranged from 1.1 to 3.5 mg/kg per day with a mean of 2.3 mg/kg per day. After 111 days of incubation at -2 °C, 14% degradation to the parent compound was observed and the BOD was 8% of the theoretical oxygen demand(1).

AEROBIC: Proylene glycol reached 90% of its theoretical BOD in 14 days in the Japanese MITI test(1). A mixture of propylene glycol, diethylene glycol and potassium acetate reached 32.9, 30.2%, and 24.1% of its theoretical BOD in 5 days, respectively at 8 °C, 4 °C and 1 °C(2). The measured surface biodegradation rates for deicing fluids, specifically propylene glycol, was 0.073 day-1(2). Aircraft deicing fluid, the major constituents being ethylene glycol and propylene glycol, reached concentrations ranging from 350-245,000 mg/L, with an average of 87,000 mg/L, of its theoretical BOD after 5 days(3).

ANAEROBIC: Using an activated sludge or digester sludge incubated under anaerobic conditions, propylene glycol was completely degraded within 5-9 days, while a sterile control showed no degradation(1). Rapid propylene glycol degradation is observed in topsoil materials high in organic matter at 20 °C; in subsoil materials, degradation of propylene glycol is very slow and incomplete(2).

Under ordinary conditions propylene glycol is stable, but at high temps it tends to oxidize giving rise to products such as propionaldehyde, lactic acid, pyruvic acid and acetic acid.

The rate constant for the vapor-phase reaction of propylene glycol with photochemically-produced hydroxyl radicals has been measured as 1.2X10-11 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 32 hours at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). Propylene glycol is not expected to undergo hydrolysis in the environment due to the lack of hydrolyzable functional groups(2). Propylene glycol does not contain chromophores that absorb at wavelengths >290 nm and therefore is not expected to be susceptible to direct photolysis by sunlight(2). The rate constant for the reaction of propylene glycol with hydroxyl radicals in aqueous solution is approximately 0.94-1.68X10+9 L/mol-sec(3); if the hydroxyl radical concn of sunlit natural water is assumed to be 1X10-17 moles/L(4), the half-life would be approximately 1.3-2.3 years(SRC).

An estimated BCF of 3 was calculated for propylene glycol(SRC), using a log Kow of -0.92(1) and a regression-derived equation(2). According to a classification scheme(3), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).

The Koc of propylene glycol is estimated as 1(SRC), using a log Kow of -0.92(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that propylene glycol is expected to have very high mobility in soil(SRC).

The Henry's Law constant for propylene glycol is estimated as 1.3X10-8 atm-cu m/mole(SRC) derived from its vapor pressure, 0.13 mm Hg(1), and assigned value for water solubility of 1X10+6 mg/L (miscible)(2). This Henry's Law constant indicates that propylene glycol is expected to be essentially nonvolatile from water surfaces(3). Propylene glycol is not expected to volatilize from dry soil surfaces(SRC) based upon its vapor pressure(1).

GROUNDWATER: Propylene glycol was detected at a concentration of 4 mg/L in samples from a perched water table at the Ottawa Airport, Ontario, Canada(1).

SURFACE WATER: Trigg Lake and Big Bear Creek, in the vicinity of the Dallas/Fort Worth International Airport, TX, were monitored for aircraft deicer/anti-icer fluid runoff from October 2002 to April 2004. Glycol concentrations at outfalls ranged from less than 81 to 23,800 mg/L; concentrations in Big Bear Creek ranged from less than 18 to 230 mg/L, with 10 and 35% of what was applied to aircraft was subsequently discharged into the creek. Glycol effluent released to Trigg Lake was initially diluted and degraded prior to reaching the lake outlet(1). Propylene glycol was detected in storm water runoff at the Salt Lake City airport Utah at concentrations up to 19,000 mg/L. The compound may also be released to surface water as a metabolite of the military propellant propylene glycol dinitrate which is found in waste water streams from munitions facilities(2).

Propylene glycol was identified, not quantified, in a wastewater effluent from a chemical plant in Memphis, TN in Aug 1974(1).

INDOOR AIR: Propylene glycol was detected in indoor air concentrations at the maximum concentration of 69.3 ug/cu m and the average concentration of 7.7 ug/cu m(1).

Propylene glycol was identified as a volatile component of latex-backed carpets(1). Propylene glycol was detected in newly manufactured and site houses at concentrations of 1.1-12.0 ppb and < 2.2-360 ppb in North America(2).

Propylene glycol was detected in snowbanks within the General Mitchell International Airport in Wisconsin, a medium-sized airport. The compound was identified as the main constituent, with the concentration ranging from 144 to 8,210 kg from February 2000-March 2003. Glycol content in snowbanks ranged from 0.17- 11.4%(1)

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.