Chloroform

Chloroform is an organic compound with the chemical formula CHCl3. [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] It is a clear, colourless, volatile, non-flammable liquid with a pleasant, sweet odour, which is detectable at ppm levels. Chloroform is slightly soluble in water. It is miscible with alcohol, benzene, petroleum ether, carbon tetrachloride, carbon disulfide and oils. Chloroform reacts vigorously with strong caustics, strong oxidants, chemically active metals such as aluminium, lithium, magnesium, sodium or potassium, and acetone, causing fire and explosion hazards. It can attack plastic, rubber and coatings. Chloroform decomposes slowly under the influence of light and air. It also decomposes on contact with hot surfaces, flames or fire, forming irritating and toxic fumes, which consist of hydrogen chloride, phosgene and chlorine. [2]

 

Uses [2]

 

Chloroform is primarily used in the production of refrigerants (e.g.

chlorofluorocarbon (CFC)-22, fluorocarbon-22), in the production of plastics (especially vinyl chloride) and in the manufacture of other chemicals. Chloroform is used as an extraction solvent for fats, oils, greases, rubber, waxes, gutta-percha, resins, lacquers, floor polishes, artificial silk manufacture, gums and adhesives. It is utilised as an industrial solvent in the extraction and purification of some antibiotics, alkaloids, vitamins and flavours. It is used as a solvent in organic chemistry, in photography and in making dyes, drugs and pesticides. Other uses are as a dry cleaning agent to remove spots, as a fumigant and in fire extinguishers to lower the freezing temperature of carbon tetrachloride. Chloroform formulated with other ingredients is used to control screwworm in animals. Chloroform is steadily being replaced by less toxic solvents and may no longer be used in some of these applications. Its use as an inhaled anaesthetic during surgery has already been largely discontinued.

 

In the Environment [3]

 

Chloroform evaporates easily into the air. Most of the chloroform in air breaks down eventually, but it is a slow process. The breakdown products in air include phosgene and hydrogen chloride, which are both toxic. Chloroform doesn’t stick to soil very well and can travel through soil to groundwater. It dissolves easily in water and some of it may break down to other chemicals. Chloroform lasts a long time in groundwater. It doesn’t appear to accumulate in great amounts in plants and animals.

 

Sources & Routes of Exposure

 

Sources of Exposure [4]

 

Chloroform may be released to the air from a large number of sources related to its manufacture and use, as well as its formation in the chlorination of drinking water, wastewater, and swimming pools. Pulp and paper mills, hazardous waste sites, and sanitary landfills are also sources of air emissions. Human exposure to chloroform may occur through drinking water, where chloroform is formed as a result of the chlorination of naturally occurring organic materials found in raw water supplies. Furthermore, chloroform may be found in some foods and beverages, largely from the use of tap water during production processes.

 

Routes of Exposure [2]

 

Chloroform can be absorbed into the body by inhalation, through the skin and by ingestion. Exposure to chloroform can occur mainly in the workplace of industries that use chloroform. Inhalation and skin contact are the most likely exposure routes. Ingestion is unlikely. The general public may be exposed to trace amounts of chloroform by drinking chlorinated water, by eating food or drinking beverages where tap water containing chloroform is used during production processes or by swimming in pools treated with chlorine.

 

Health Effects [4]

 

Acute Effects

 

The major effect from acute inhalation exposure to chloroform in humans is central nervous system depression. At very high levels (40,000 ppm), chloroform exposure may result in death, with concentrations in the range of 1,500 to 30,000 ppm producing anaesthesia, and lower concentrations (<1,500 ppm) resulting in dizziness, headache, tiredness, and other effects. Effects noted in humans exposed to chloroform via anaesthesia include changes in respiratory rate, cardiac effects, gastrointestinal effects, such as nausea and vomiting, and effects on the liver and kidney. In humans, a fatal oral dose of chloroform may be as low as 10 mL (14.8 g), with death due to respiratory or cardiac arrest. Tests involving acute exposure of animals have shown chloroform to have low acute toxicity from inhalation exposure and moderate acute toxicity from oral exposure.

 

Chronic Effects

 

Chronic exposure to chloroform by inhalation in humans is associated with effects on the liver, including hepatitis and jaundice, and central nervous system effects, such as depression and irritability. Inhalation exposures of animals have also resulted in effects on the kidney. Chronic oral exposure to chloroform in humans has resulted in effects on the blood, liver, and kidney. EPA has not established a Reference Concentration (RfC) for chloroform. The California Environmental Protection Agency (CalEPA) has established a chronic reference exposure level of 0.3 milligrams per cubic metre (mg/m3) for chloroform based on exposures resulting in kidney and liver effects in rats. ATSDR has established an acute inhalation minimal risk level (MRL) of 0.5 mg/m3 (0.1 ppm) based on exposures resulting in liver effects in mice, an intermediate inhalation MRL of 0.2 mg/m3 (0.05 ppm) based on worker exposures resulting in liver effects in humans, and a chronic inhalation. The Reference Dose (RfD) for chloroform is 0.01 milligrams per kilogram per day (mg/kg/d) based on exposures resulting in fatty cyst formation in the livers of dogs.

 

Reproductive/Developmental Effects

 

Little information is available on the reproductive or developmental effects of chloroform in humans, via any route of exposure. A possible association between certain birth outcomes (e.g., low birth weight, cleft palate) and consumption of contaminated drinking water was reported. However, because multiple contaminants were present, the role of chloroform is unclear. Animal studies have demonstrated developmental effects, such as decreased foetal body weight, foetal resorptions, and malformations in the offspring of animals exposed to chloroform via inhalation. Reproductive effects, such as decreased conception rates, decreased ability to maintain pregnancy, and an increase in the percentage of abnormal sperm were observed in animals exposed to chloroform through inhalation. Animal studies have noted decreased foetal weight, increased foetal resorptions, but no evidence of birth defects, in animals orally exposed to chloroform.

 

Cancer Risk

 

No information is available regarding cancer in humans or animals after inhalation exposure to chloroform. Epidemiologic studies suggest an association between cancer of the large intestine, rectum, and/or bladder and the constituents of chlorinated drinking water, including chloroform. However, there are no epidemiologic studies of water containing only chloroform. Chloroform has been shown to be carcinogenic in animals after oral exposure, resulting in an increase in kidney and liver tumours. EPA considers chloroform to be a probable human carcinogen and has ranked it in EPA’s Group B2. EPA has determined that although chloroform is likely to be carcinogenic to humans by all routes of exposure under high-exposure conditions that lead to cell death and regrowth in susceptible tissues, chloroform is not likely to cause cancer in humans by any route of exposure under exposure conditions that do not cause cell death and regrowth. Therefore, EPA has not derived either an oral carcinogenic potency slope or an inhalation unit risk for chloroform.

 

Safety [5]

 

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.
  • 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 antibacterial 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: Do NOT induce vomiting unless directed to do so by medical personnel. Never give anything by mouth to an unconscious person. If large quantities of this material are swallowed, call a physician immediately. Loosen tight clothing such as a collar, tie, belt or waistband.

 

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 chloroform:

  • Splash goggles;
  • 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 [2,5,6]

 

United States

 

OSHA: The United States Occupational Safety and Health Administration permissible exposure limit (PEL) for chloroform is 50 ppm (240 milligrams per cubic metre (mg/m3) as a ceiling limit.

A worker’s exposure to chloroform shall at no time exceed this ceiling level [29 CFR 1910.1000, Table Z-1].

 

NIOSH: The National Institute for Occupational Safety and Health (NIOSH) has established a recommended exposure limit (REL) for chloroform of 2 ppm (9.78 mg/m3) as a 60-minute short-term exposure limit (STEL). NIOSH also considers chloroform a potential occupational carcinogen [NIOSH 1992].

 

ACGIH: The American Conference of Governmental Industrial Hygienists (ACGIH) has assigned chloroform a threshold limit value (TLV) of 10 ppm (49 mg/m3) as a TWA for a normal 8-hour workday and a 40-hour workweek. The ACGIH also considers chloroform a suspected human carcinogen (A2 substance) [ACGIH 1994, p. 16].

 

Australia

 

Safe Work Australia has set the exposure standard for chloroform to 10 ppm (equivalent to 49 milligram/m3) (TWA).

 

Australian Drinking Water Guidelines (NHMRC and ARMCANZ, 1996): Maximum of 0.25 mg/L (i.e. 0.00025 g/L).

 

United Kingdom

 

Inhalation TWA: 2 (ppm)

Inhalation TWA: 9.9 (mg/m3)

 

References

  1. http://en.wikipedia.org/wiki/Chloroform
  2. http://www.npi.gov.au/substances/chloroform/index.html
  3. http://www.atsdr.cdc.gov/tfacts6.pdf
  4. http://www.epa.gov/ttn/atw/hlthef/chlorofo.html
  5. http://www.sciencelab.com/msds.php?msdsId=9927133
  6. http://www.osha.gov/SLTC/healthguidelines/chloroform/recognition.html

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