Chloroacetic Acid

Chloroacetic acid, industrially known as monochloroacetic acid (MCA), is the organochlorine compound with the formula ClCH2CO2H. This carboxylic acid is a useful building-block in organic synthesis. [1] Liquid chloroacetic acid is a colourless solution of the white crystalline solid. The acid concentration can be up to 80%. In solid form, chloroacetic acid is colourless to light-brown crystalline material. In water, it is soluble and sinks. It is corrosive to metals and tissue. [2] The odour of chloroacetic acid is penetrating, similar to vinegar. [3]

Uses [3]

Chloroacetic acid is used in the manufacture of cellulose ethers (used mainly for drilling muds, detergents, food, and pharmaceuticals), as a post-emergence contact herbicide and defoliant, and in the manufacture of glycine and thioglycolic acid. It is also used in the manufacture of various dyes, synthetic caffeine, and organic chemicals.

Sources & Routes of Exposure

Sources of Exposure [3]

  • Individuals are most likely to be exposed to chloroacetic acid in the workplace.
  • Chloroacetic acid may be released to the environment during its production and use.

Routes of Exposure [4]

Chloroacetic acid can be absorbed into the body by inhalation and contact with the skin and eyes. It can also enter the body via ingestion.

Health Effects [3]

Acute Effects

  • Acute inhalation or dermal exposure to chloroacetic acid may cause severe damage to the skin and mucous membranes in humans. Chloroacetic acid irritates and may burn the skin, eyes, and respiratory tract.
  • Depression of the central nervous system may occur in humans following acute inhalation exposure.
  • Acute exposure by ingestion of chloroacetic acid may interfere with essential enzyme systems in the body and cause intestinal perforation and peritonitis in humans.
  • Mice acutely exposed by ingestion have exhibited neurological dysfunction.
  • Tests involving acute exposure of animals in rats, mice, and guinea pigs have demonstrated chloroacetic acid to have extreme toxicity from inhalation and moderate to high acute toxicity from ingestion.

Chronic Effects

  • No information is available on the chronic effects of chloroacetic acid in humans.
  • Damage to the respiratory tract, including inflammatory changes in the respiratory organs, inflammatory lesions of the nasal mucosa, metaplasia of the olfactory epithelium, and respiratory congestion, have been observed in rodents chronically exposed to chloroacetic acid by inhalation, orally, and via gavage.
  • Chronic exposure via gavage has resulted in myocarditis (inflammation of the muscular tissue of the heart wall) and mortality due to myocardial failure in rats and hepatic vacuolar degeneration in mice.
  • EPA has not established a Reference Concentration (RfC) for chloroacetic acid.
  • EPA has calculated a provisional Reference Dose (RfD) of 0.002 milligrams per kilogram body weight per day (mg/kg/d) for chloroacetic acid.

Reproductive/Developmental Effects

  • No information is available on the reproductive or developmental effects of chloroacetic acid in humans or animals.

Cancer Risk

  • No information is available on the carcinogenic effects of chloroacetic acid in humans.
  • Chloroacetic acid was not found to be tumorigenic to mice when administered via gavage or by subcutaneous injection or when applied to the skin.
  • In a National Toxicology Program (NTP) study, no statistically significant increases in tumour incidences were reported in rats and mice exposed to chloroacetic acid via gavage.
  • EPA has not classified chloroacetic acid for potential carcinogenicity.

Safety [5]

First Aid Measures

  • Eye Contact: Check for and remove any contact lenses. Immediately flush eyes with running water for at least 15 minutes, keeping eyelids open. Cold water may be used. Do not use an eye ointment. Seek medical attention.
  • Skin Contact: If the chemical got onto the clothed portion of the body, remove the contaminated clothes as quickly as possible, protecting your own hands and body. Place the victim under a deluge shower. If the chemical got on the victim’s exposed skin, such as the hands: Gently and thoroughly wash the contaminated skin with running water and non-abrasive soap. Be particularly careful to clean folds, crevices, creases and groin. Cold water may be used. If irritation persists, seek medical attention. Wash contaminated clothing before reusing.
  • Serious Skin Contact: Wash with a disinfectant soap and cover the contaminated skin with an anti-bacterial cream. Seek immediate medical attention.
  • Inhalation: Allow the victim to rest in a well-ventilated area. Seek immediate 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 immediate medical attention.
  • Ingestion: Do not induce vomiting. Examine the lips and mouth to ascertain whether the tissues are damaged, a possible indication that the toxic material was ingested; the absence of such signs, however, is not conclusive. Loosen tight clothing such as a collar, tie, belt or waistband. If the victim is not breathing, perform mouth-to-mouth resuscitation. Seek immediate medical attention.

Exposure Controls & Personal Protection

Engineering Controls

  • Use process enclosures, local exhaust ventilation, or other engineering controls to keep airborne levels below recommended exposure limits.
  • If user operations generate dust, fume or mist, use ventilation to keep exposure to airborne contaminants below the exposure limit.

Personal Protective Equipment

The following personal protective equipment is recommended when handling chloroacetic acid:

  • Splash goggles;
  • Synthetic apron;
  • Vapour and dust 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 and dust 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.


United States [4]

No exposure limits have been set for chloroacetic acid.

Australia [6]

Safe Work Australia: Safe Work Australia has set a time weighted average (TWA) concentration for monochloroacetic acid of 0.3ppm or 1.2mg/m3 for a 40 hour work week.