Vinylidene Chloride (1,1 -Dichloroethylene)
75-35-4
Hazard Summary
Vinylidene chloride is used as an intermediate in chemical synthesis and to produce polyvinylidene chloride
copolymers. The primary acute (short-term) effects in humans from vinylidene chloride exposure are on
the central nervous system (CNS), including CNS depression and symptoms of inebriation, convulsions,
spasms, and unconsciousness at high concentrations. Low-level, chronic (long-term) inhalation exposure
of vinylidene chloride in humans may effect the liver. Animal studies indicate that chronic exposure to
vinylidene chloride can affect the liver, kidneys, CNS and lungs. Human data are considered inadequate in
providing evidence of cancer from exposure to vinylidene chloride. The most recent cancer classification
for vinylidene chloride can be found on IRIS.
Please Note: The main sources of information for this fact sheet are the Agency for Toxic Substances and Disease
Registry's (ATSDR's) Toxicological Profile for 1,1 -Dichloroethene (1) and EPA's Integrated Risk Information
System (IRIS) (4), which contains information on oral chronic toxicity and the RfD, and the carcinogenic effects of
vinylidene chloride including the unit cancer risk for inhalation exposure.
Uses
s Vinylidene chloride is used as an intermediate for organic chemical synthesis. (1)
s Vinylidene chloride is also used in the production of polyvinylidene chloride copolymers. The major
application of these ^chloride copolymers is in the production of flexible films for food packaging
(SARAN and VELON wraps). (1)
a These copolymers are also used extensively in many types of packing materials, as flame retardant coatings
for fiber and carpet backing and in piping, coating for steel pipes, and adhesive applications. (2)
Sources and Potential Exposure
a Air releases, primarily from emissions from polymer synthesis and fabrication industries, are the greatest
source of ambient vinylidene chloride. (1)
a Occupational exposure to vinylidene chloride may occur by inhalation or dermal contact. (1)
a Vinylidene chloride has been detected at low levels in a number of drinking water supplies across the
United States. (1)
Assessing Personal Exposure
a Measurable levels of vinylidene chloride can be detected in the breath, blood, urine, and body tissues.
Determination of vinylidene chloride in breath samples by gas chromatography/mass spectrometry is the
most commonly used method of monitoring exposure to vinylidene chloride. (1)
Health Hazard Information
Acute Effects:
• Studies in humans indicate that relatively high concentrations of inhaled vinylidene chloride can induce
adverse neurological effects including CNS depression and symptoms of inebriation, convulsions, spasms,

-------
and unconsciousness, and respiratory effects, such as inflammation of mucous membranes. (1,2)
Acute animal tests in rats have shown vinylidene chloride to have high toxicity from oral exposure
and moderate toxicity from inhalation exposure. (3)
Chronic Effects (Noncancer):
s Several studies have suggested that vinylidene chloride may effect the liver in humans. (1,2)
a Animal studies have shown that chronic exposure to vinylidene chloride causes effects on the kidneys, liver,
CNS and lungs. (1,2,3)
s The Reference Dose (RfD) for vinylidene chloride can be found on IRIS. The RfD is an estimate (with
uncertainty spanning perhaps an order of magnitude) of a daily ingestion exposure to the human
population (including sensitive subgroups) that is likely to be without appreciable risk of deleterious
noncancer effects during a lifetime. It is not a direct estimator of risk but rather a reference point to gauge
the potential effects. At exposures increasingly greater than the RfD, the potential for adverse health
effects increases. Lifetime exposure above the RfD does not imply that an adverse health effect would
necessarily occur. (4)
a The California Environmental Protection Agency (CalEPA) has established a chronic reference exposure level
of 0.02 milligrams per cubic meter (mg/m ) for vinylidene chloride based on liver effects in guinea pigs.
The CalEPA reference exposure level is a concentration at or below which adverse health effects are not
likely to occur. (7)
Reproductive/Develop mental Effects:
a No studies were located regarding developmental or reproductive effects in humans. (1,2)
a Birth defects were noted in the offspring of pregnant rats and mice that had been exposed to vinylidene
chloride in air. In this study, maternal toxicity was observed at developmentally toxic concentrations. (1)
Cancer Risk:
a No relationship between the occurrence of cancer in humans and occupational exposure to vinylidene
chloride has been demonstrated. However, only three studies are available and these studies are limited by
small population sizes and short observation periods. (1,2)
a One study showed an increase in kidney and mammary tumors in mice exposed to vinylidene chloride via
inhalation, while a drinking water study showed an increase in adrenal tumors in male rats. (1,2)
a A study by the National Toxicology Program (NTP) did not show an increase in tumors in rats and mice
exposed to vinylidene chloride via gavage (experimentally placing the chemical in the animal's stomachs).(8)
EPA uses mathematical models, based on animal studies, to estimate the probability of a person developing
¦ cancer from breathing air con ta ining a sp ecified concentration of a chemical. EPA calculated an
- 5	3 -1
inhalation unit risk estimate of 5.0 x 1 0 (pg/m ) . EPA estimates that, if an individual were to
3-5	3
continuously breathe air containing vinylidene chloride at an average of 0.02 |jg/m (2x10 mg/m ) over
his or her entire lifetime, that person would theoretically have no more than a one-in-a-million increased
chance of developing cancer as a direct result of brea t^hing air ^containing this chemical. Similarly, EPA
estimates that breathing air containing 0.2 |jg/m (2x10 mg/m ) would result in not greater than a one-
3
in-a-hundred thousand increased chance of developing cancer, and air containing 2.0 |jg/m (2 x
1 0 mg/m ) would result in not greater than a one-in-ten thousand increased chance of developing
cancer. For a detailed discussion of confidence in the potency estimates, please see IR 1^ S. (4)
EPA has calculated an oral cancer slope factor of 0.6 (mg/kg/d) . (4)
Physical Properties
8 Vinylidene chloride is a colorless liquid with a mild sweet odor resembling that of chloroform. (1,5)
a The chemical formula for vinylidene chloride is ^H^CI^ and the molecular weight is 96.95 g/mol. (1,5)
The vapor pressure for vinylidene chloride is 591 mm Hg at 2 5 °C and it has a log octanol/water partition

-------
s The vapor pressure for vinylidene chloride is 591 mm Hg at 25 °C and it has a log octanol/water partition
coefficient (log K ) of 1.32.(1)
o w
• Vinylidene chlorid e has an odor threshold of 1 90 parts per million (ppm). (6)
a Vinylidene chloride is practically insoluble in water. (1,5)
Conversion Factors:
3	3
To convert concentrations in air (at 2 5 °C) from ppm to mg/m : mg/m = (ppm) x (molecular weight of the
compound)/(24.45). For vinylidene chloride: 1 ppm = 4.0 mg/m .
Health Data from Inhalation Exposure
1,1 -Dichloroethylene
1000000
100000
10000
1000
® 100
E
Bi
10
c
d
1
£
5
0.1
0j01
0.001
OjOOOI
0.00001
Health numbers"
LCB(rat^ (2 5^177 nng/rr?)
NCAELC (liver)
(20 mg/rrb
LCAEL (InrarJ
(Si nrg/rrb
CalEPA chronic refererce
exposure level
(0.02 mg/nrft
- EPA Canoar Risk
Level (1-irva-
rnil I ion excess
" lifetime risk =
ixlO^nrg/m^
	BeL	
4
Regulatory, advisory
numbers'"
ACGIH TLV
(20 mg/nn5)
ACGIH TLV—American 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.
LC (Lethal Concentration )—A 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.
LOAEL—Lowest-observed-adverse-effect level.
NOAEL—No-observed-adverse-effect level.
The health and regulatory values cited in this factsheet were obtained in December 1999.
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. ACGIH numbers are advisory.

-------
Th is NOAEL and LOAEL are from the critical study used as the basis for the CalEPA chronic reference exposure
level.
Summary created in April 1 992, updated in January 2000
References
1.	Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for 1,1 -Dichloroethene.
(Update). Public Health Service, U.S. Department of Health and Human Services, Atlanta, CA. 1 994.
2.	U.S. Department of Health and Human Services. Hazardous Substances Data Bank (HSDB, online database).
National Library of Medicine, National Toxicology Information Program, Bethesda, MD. 1 993.
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 Dichloroethylene.
National Center for Environmental Assessment, Office of Research and Development, Washington, DC.
1999.
5.	The Merck Index. An Encyclopedia of Chemicals, Drugs, and Biologicals. 1 1 th ed. Ed. S. Budavari. Merck
and Co. Inc., Rahway, NJ. 1 989.
6.	J.E. Amoore and E. Hautala. Odor as an aid to chemical safety: Odor thresholds compared with threshold
limit values and volatilities for 21 4 industrial chemicals in air and water dilution. Journal of Applied
Toxicology, 3(6):272-290. 1 983.
7.	California Environmental Protection Agency (CalEPA). Air Toxics Hot Spots Program Risk Assessment
Guidelines: Part III. Technical Support Document for the Determination of Noncancer Chronic Reference
Exposure Levels. SRP Draft. Office of Environmental Health Hazard Assessment, Berkeley, CA. 1 999.
8.	National Toxicology Program. Carcinogenesis	•" ;	! ¦ in
F344/N Rats and B6C3F^ Mice (Gavaae Study). TR No. 228. U.S. Department of Health and Human Services,
Public Health Service, National Institutes of Health, Bethesda, MD. 1 982.
9.	American Conference of Governmental Industrial Hygienists (ACGIH). 1 999 TLVs and BEIs. Threshold Limit
Values for Chemical Substances and Physical Agents. Biological Exposure Indices. Cincinnati, OH. 1 999.

-------