Chloroacetic acid, also known as monochloroacetic acid (MCA), is an organochlorine compound with the formula ClCH2CO2H. It is a key building block in organic synthesis. In its liquid form, MCA appears as a colourless solution with an acid concentration of up to 80%. In its solid form, it is a colourless to light-brown crystalline material. It is soluble in water and sinks when mixed. MCA is highly corrosive to both metals and human tissue. It has a strong, penetrating odour similar to vinegar.
What is Chloroacetic Acid used for?
Chloroacetic acid is widely used in various industries. It is an essential component in the manufacture of cellulose ethers, which are used in drilling muds, detergents, food, and pharmaceuticals. It is also applied as a post-emergence contact herbicide and defoliant. Additionally, it plays a role in producing glycine, thioglycolic acid, dyes, synthetic caffeine, and other organic chemicals.
Chloroacetic acid is used in the manufacture of cellulose ethers, which is mainly used for detergents.
Sources & Routes of Exposure
Sources of Exposure
Workplace exposure is the most common source.
Environmental release can occur during production and use.
Routes of Exposure
Chloroacetic acid can enter the body through:
Inhalation (breathing it in).
Skin or eye contact.
Ingestion (swallowing).
Health Effects
Acute Effects:
Severe irritation and burns to the skin, eyes, and respiratory tract.
Depression of the central nervous system after inhalation exposure.
Ingestion can interfere with enzyme systems, leading to intestinal damage and peritonitis.
Neurological dysfunction has been observed in mice.
Extremely toxic in animals via inhalation; moderate to highly toxic if ingested.
Chronic Effects:
No human data is available.
In rodent studies, chronic exposure caused:
Respiratory damage, including nasal inflammation and congestion.
Heart inflammation (myocarditis) and mortality from heart failure in rats.
Liver damage in mice.
EPA Reference Dose (RfD): 0.002 mg/kg/day.
Reproductive/Developmental Effects:
No data is available on reproductive or developmental toxicity.
Cancer Risk:
No human data is available.
Not tumorigenic in mice when tested via ingestion, skin application, or injection.
The NTP study found no significant tumour increase in rats or mice.
Not classified for carcinogenicity by the EPA.
Safety
First Aid Measures
Eye Contact: Flush eyes with water for at least 15 minutes. Seek medical attention.
Skin Contact: Remove contaminated clothing. Wash skin with water and soap. Seek medical attention if irritation persists.
Serious Skin Exposure: Wash with disinfectant soap, apply antibacterial cream, and get immediate medical attention.
Inhalation: Move to fresh air. If breathing is difficult, administer oxygen. Seek medical attention.
Serious Inhalation Exposure: Use a self-contained breathing apparatus. Seek immediate medical attention.
Ingestion: Do not induce vomiting. Seek immediate medical attention.
Exposure Controls & Personal Protection
Engineering Controls
Use ventilation, enclosures, or local exhaust to keep airborne exposure below limits.
Personal Protective Equipment (PPE)
Eye Protection: Splash goggles.
Skin Protection: Synthetic apron, gloves.
Respiratory Protection: Vapour and dust respirator (approved type).
For Large Spills: Full protective suit, boots, self-contained breathing apparatus.
Suggested protective clothing may not be sufficient—consult a specialist before handling.
Regulations
United States:
No exposure limits have been set for chloroacetic acid.
Australia:
Safe Work Australia has established a time-weighted average (TWA) concentration limit of 0.3 ppm or 1.2 mg/m³ for a 40-hour workweek.
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