1,1-Dichloroethylene is also known as 1,1-Dichloroethene, vinylidene chloride, or 1,1-DCE, this chemical is an organochloride with the formula C₂H₂Cl₂. It is a colourless liquid with a sharp odour that evaporates quickly and burns easily at room temperature.
1,1-Dichloroethylene is a manmade substance — it does not occur naturally in the environment. Like most chlorinated compounds, it doesn’t dissolve well in water, but it dissolves easily in organic solvents.
It was once used to make cling-wrap for food, but this use has been phased out.
What is 1,1-Dichloroethylene used for?
1,1-Dichloroethylene is used to make various types of plastics and coatings, including
Flexible films (e.g., food wraps)
Packaging materials
Flame-retardant coatings (for fibres and carpet backings)
Plastic piping
Steel pipe coatings
Adhesives
1,1-Dichloroethylene is used to make various types of plastics such as packaging materials.
In the Environment
1,1-Dichloroethylene gets into the environment mainly from factories that make or use it.
Evaporates quickly from water and soil into the air
In the air, it breaks down in about 4 days
In water, it breaks down very slowly
It does not build up much in fish or birds
In soil, it slowly changes into less harmful chemicals
Sources and Routes of Exposure
Sources of Exposure
People can be exposed to 1,1-dichloroethylene in several ways:
Workplaces that make or use the chemical
Plastic food wraps (though levels are regulated for safety)
Drinking water – around 3% of supplies may contain very low levels
Air near factories or hazardous waste sites
Routes of Exposure
The main ways people can be exposed include
Inhalation (breathing in vapours)
Skin contact and absorption
Eye contact
Ingestion (eating or drinking contaminated items)
Health Effects
Acute Effects
Breathing in high levels of 1,1-dichloroethylene can cause neurological symptoms in humans such as:
Central nervous system (CNS) depression
Feelings of inebriation (like being drunk)
Convulsions, muscle spasms, and even unconsciousness
Irritation of the nose, throat, and mucous membranes
In animal studies, rats showed:
High toxicity when the chemical was swallowed (oral exposure)
Moderate toxicity when it was inhaled
Chronic Effects
Long-term exposure to 1,1-dichloroethylene may lead to liver damage in humans.
Animal studies show that repeated exposure can affect
Kidneys
Liver
Central nervous system
Lungs
The Reference Dose (RfD)—an estimate of safe daily exposure — is available on the EPA’s IRIS database.
The California EPA (CalEPA) has set a chronic reference exposure level of 0.02 mg/m³, based on liver effects observed in guinea pigs. This is the level below which health effects are not expected to occur.
Reproductive and developmental Effects
There are no known studies on reproductive or developmental effects in humans.
However, in animal studies:
Birth defects were seen in the offspring of rats and mice exposed to the chemical in air.
These effects occurred at levels that also caused harm to the pregnant animals themselves, suggesting maternal toxicity was involved.
Cancer Risk
In humans, current research has not confirmed a link between 1,1-dichloroethylene and cancer. However, the available studies are
Limited in number (only three)
Have small sample sizes
And short study durations
In animal studies:
Mice exposed by inhalation showed kidney and mammary (breast) tumours
Rats exposed through drinking water showed adrenal gland tumours
However, a study by the National Toxicology Program (NTP) did not find increased tumours in rats or mice when the chemical was given orally (by gavage)
The EPA has assigned an oral cancer slope factor of 0.6 (mg/kg/day)⁻¹, which is used to estimate cancer risk from long-term exposure.
Safety
First Aid Measures
Eye Contact:
Remove contact lenses if present.
Flush eyes with plenty of warm water for at least 15 minutes.
Seek medical attention if irritation persists.
Skin Contact:
Rinse skin immediately with plenty of water.
Use an emollient (soothing cream) on irritated skin.
Remove contaminated clothing and shoes.
Wash clothing and clean shoes before reuse.
Get medical help if needed.
Serious Skin Contact:
Wash with disinfectant soap.
Apply an anti-bacterial cream.
Get immediate medical attention.
Inhalation:
Move person to fresh air.
If not breathing, give artificial respiration.
If breathing is difficult, provide oxygen.
Seek medical attention.
Serious Inhalation:
Evacuate the victim to a safe area.
Loosen tight clothing (e.g., collars, belts).
Provide oxygen or mouth-to-mouth resuscitation only if safe – avoid if the material is toxic or corrosive.
Seek immediate medical help.
Ingestion:
Do not induce vomiting unless told to by a healthcare professional.
Never give anything by mouth to an unconscious person.
Loosen tight clothing.
Get medical help immediately.
Fire and Explosion Information
1,1-Dichloroethylene is a flammable liquid
Auto-ignition temperature: 520°C (968°F)
Combustion can produce:
Carbon monoxide (CO)
Carbon dioxide (CO₂)
Halogenated compounds
Firefighting measures:
For small fires: Use dry chemical powder.
For large fires: Use alcohol-resistant foam, water spray, or fog.
Cool containers with water jets to prevent pressure build-up, explosion, or auto-ignition.
Exposure Control & Personal Protection
Engineering Controls
Provide exhaust ventilation to keep vapour levels below limits.
Make sure eyewash stations and safety showers are nearby.
Personal Protective Equipment (PPE)
When handling 1,1-dichloroethylene, wear:
Safety glasses
Lab coat
Chemical-resistant gloves
Approved vapour respirator
For large spills, additional protection includes
Splash goggles
Full protective suit
Vapour respirator
Boots
Self-contained breathing apparatus (SCBA)
Protective clothing may not be enough — consult a safety specialist before working with this chemical.
Regulation
United States
OSHA: The Occupational Safety and Health Administration has set an occupational exposure limit of 1 ppm for 1,1-dichloroethylene in workplace air for an 8-hour workday, 40-hour workweek.
NIOSH: The National Institute for Occupational Safety and Health currently recommends that workers breathe as little 1,1-dichloroethylene as possible.
EPA: The Environmental Protection Agency has set a limit in drinking water of 0.007 parts of 1,1-dichloroethylene per million parts of drinking water (0.007 ppm). EPA requires that discharges or spills into the environment of 5,000 pounds or more of 1,1-dichloroethylene be reported.
Australia
Safe Work Australia: Safe Work Australia has established a time weighted average (TWA) concentration for 1,1-dichloroethylene of 5ppm or 20mg/m3 for a 40-hour workweek. In addition, a 15-minute time-weighted average (TWA) exposure limit (STEL) of 20ppm or 79mg/m3 has been set. These limits must not be exceeded at any time during an 8-hour working day exposure limit.
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