1,1-Dichloroethylene

1,1-dichloroethylene, also called1,1-Dichloroethene, vinylidene chloride or1,1-DCE, is anorganochloridewith the molecular formula C2H2Cl2. It is a colourless liquid with a sharp odour. [fusion_builder_container hundred_percent=”yes” overflow=”visible”][fusion_builder_row][fusion_builder_column type=”1_1″ background_position=”left top” background_color=”” border_size=”” border_color=”” border_style=”solid” spacing=”yes” background_image=”” background_repeat=”no-repeat” padding=”” margin_top=”0px” margin_bottom=”0px” class=”” id=”” animation_type=”” animation_speed=”0.3″ animation_direction=”left” hide_on_mobile=”no” center_content=”no” min_height=”none”][1] 1,1-Dichloroethylene turns into a vapour quickly at room temperature and burns fast. 1,1-Dichloroethylene is a manmade chemical and is not found naturally in the environment. [2] Like most chlorocarbons, it is poorly soluble in water, but soluble in organic solvents. 1,1-dichloroethylene was the precursor to the original cling-wrap for food, but this application has been phased out. [1]

 

Uses [3]

 

1,1-Dichloroethylene is used to make certain plastics, such as flexible films like food wrap, and in packaging materials. It is also used to make flame retardant coatings for fibre and carpet backings, and in piping, coating for steel pipes, and in adhesive applications.

 

In the Environment [3]

 

  • 1,1-Dichloroethylene enters the environment from industries that make or use it.
  • 1,1-Dichloroethylene evaporates very quickly from water and soil to the air.
  • In the air, it takes about 4 days for it to break down.
  • 1,1-Dichloroethylene breaks down very slowly in water.
  • It does not accumulate very much in fish or birds.
  • In soil, 1,1-Dichloroethylene is slowly transformed to other less harmful chemicals.

 

Sources & Routes of Exposure

 

Sources of Exposure [3]

 

  • Workers may be exposed in industries that make or use 1,1-dichloroethylene.
  • Food that is wrapped in plastic wrap may contain very low levels of 1,1-dichloroethylene. The government controls these levels to prevent harm to your health.
  • A small percentage (3%) of the drinking water supplies may contain very low levels of 1,1-dichloroethylene.
  • Air near factories that make or use 1,1-dichloroethylene and air near hazardous waste sites may contain low levels of it.

 

Routes of Exposure [4]

 

The main routes of exposure to 1,1-dichloroethylene are:

  • Inhalation,
  • Skin absorption,
  • Ingestion, and
  • Skin and/or eye contact

 

Health Effects [5]

 

Acute Effects

 

  • Studies in humans indicate that relatively high concentrations of inhaled 1,1-dichloroethylene can induce adverse neurological effects including central nervous system(CNS) depression and symptoms of inebriation, convulsions, spasms, and unconsciousness, and respiratory effects, such as inflammation of mucous membranes.
  • Acute animal tests in rats have shown 1,1-dichloroethylene to have high toxicity from oral exposure and moderate toxicity from inhalation exposure.

Chronic Effects

 

  • Several studies have suggested that 1,1-dichloroethylene may affect the liver in humans.
  • Animal studies have shown that chronic exposure to 1,1-dichloroethylene causes effects on the kidneys, liver, CNS and lungs.
  • The Reference Dose (RfD) for 1,1-dichloroethylene can be found on IRIS.
  • The California Environmental Protection Agency (CalEPA) has established a chronic reference exposure level of 0.02 milligrams per cubic metre (mg/m3) for 1,1-dichloroethylene 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.

 

Reproductive/Developmental Effects

 

  • No studies were located regarding developmental or reproductive effects in humans.
  • Birth defects were noted in the offspring of pregnant rats and mice that had been exposed to 1,1-dichloroethylene in air. In this study, maternal toxicity was observed at developmentally toxic concentrations.

 

Cancer Risk

 

  • No relationship between the occurrence of cancer in humans and occupational exposure to 1,1-dichloroethylene has been demonstrated. However, only three studies are available and these studies are limited by small population sizes and short observation periods.
  • One study showed an increase in kidney and mammary tumours in mice exposed to 1,1-dichloroethylene via inhalation, while a drinking water study showed an increase in adrenal tumours in male rats.
  • A study by the National Toxicology Program (NTP) did not show an increase in tumours in rats and mice exposed to 1,1-dichloroethylene via gavage (experimentally placing the chemical in the animal’s stomachs).
  • EPA has calculated an oral cancer slope factor of 0.6 (mg/kg/d)-1.

 

Safety [6]

 

First Aid Measures

 

  • Eye Contact: check for and remove any contact lenses. In case of contact, immediately flush eyes with plenty of water for at least 15 minutes. Cold water may be used. WARM water MUST be used. Get medical attention if irritation occurs.
  • Skin Contact: In case of contact, immediately flush skin with plenty of water. Cover the irritated skin with an emollient. Remove contaminated clothing and shoes. Wash clothing before reuse. Thoroughly clean shoes before reuse. Get medical attention.
  • Serious Skin Contact: Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek immediate medical attention.
  • Inhalation: If inhaled, remove to fresh air. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. Get medical attention.
  • Serious Inhalation: Evacuate the victim to a safe area as soon as possible. Loosen tight clothing such as a collar, tie, belt or waistband. If breathing is difficult, administer oxygen. If the victim is not breathing, perform mouth-to-mouth resuscitation. WARNING: It may be hazardous to the person providing aid to give mouth-to-mouth resuscitation when the inhaled material is toxic, infectious or corrosive. Seek medical attention.
  • Ingestion: If swallowed, do not induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. Loosen tight clothing such as a collar, tie, belt or waistband. Get medical attention immediately.

 

Fire & Explosion Information

 

  • 1,1-dichloroethylene is a flammable liquid, which is soluble or dispersed in water.
  • Auto-ignition temperature is 520°C (968°F).
  • Products of combustion include carbon oxides (CO, CO2) and halogenated compounds.
  • Dry chemical powder should be used to fight small fires.
  • Alcohol foam, water spray or fog should be used to extinguish large fires.
  • Cool containing vessels with water jet in order to prevent pressure build-up, autoignition or explosion.

 

Exposure Controls & Personal Protection

 

Engineering Controls

 

  • Provide exhaust ventilation or other engineering controls to keep the airborne concentrations of vapours below their respective threshold limit value.
  • Ensure that eyewash stations and safety showers are proximal to the workstation location.

 

Personal Protective Equipment

 

The following personal protective equipment is recommended when handling 1,1-dichloroethylene:

  • Safety glasses;
  • Lab coat;
  • Vapour respirator (be sure to use an approved/certified respirator or equivalent);
  • Gloves.

 

Personal Protection in Case of a Large Spill:

  • Splash goggles;
  • Full suit;
  • Vapour respirator;
  • Boots;
  • Gloves;
  • A self-contained breathing apparatus should be used to avoid inhalation of the product.
  • Suggested protective clothing might not be sufficient; consult a specialist BEFORE handling this product.

 

Regulation

United States [3]

 

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 [7]

 

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.

 

References

 

  1. http://en.wikipedia.org/wiki/1,1-Dichloroethene
  2. http://dhss.delaware.gov/dhss/dph/files/dichlethene11faq.pdf
  3. http://www.atsdr.cdc.gov/toxfaqs/tf.asp?id=721&tid=130
  4. http://www.cdc.gov/niosh/npg/npgd0661.html
  5. http://www.epa.gov/ttnatw01/hlthef/di-ethyl.html
  6. http://www.sciencelab.com/msds.php?msdsId=9925419
  7. http://www.safeworkaustralia.gov.au/sites/SWA/about/Publications/Documents/772/Workplace-exposure-standards-airborne-contaminants.pdf

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