Methyl methacrylate (MMA) is an organic compound with the chemical formula CH₂=C(CH₃)COOCH₃. It is the methyl ester of methacrylic acid (MAA) and is widely used in industry as a monomer for producing poly(methyl methacrylate) (PMMA)—commonly known by trade names like Plexiglas.
Methyl methacrylate is a colourless liquid with a sharp, fruity smell. It is flammable, slightly soluble in water, and readily dissolves in some organic solvents.
Methyl methacrylate plays a key role in the production of methacrylate resins and plastics, especially PMMA. Its principal applications include:
When released into the environment, methyl methacrylate evaporates quickly into the air. It can dissolve in water and tends to enter the atmosphere during industrial processes. It may also evaporate from soil or water that is exposed to air.
In the air, MMA breaks down into other compounds. Microorganisms in soil and water can also degrade it. Since MMA doesn’t bind well to soil, it may leach into groundwater. Plants and animals are unlikely to accumulate MMA in their systems.
Exposure to methyl methacrylate is most likely in:
Contaminated drinking water may also be a potential source of exposure.
The primary exposure routes include:
MMA is quickly broken down and eliminated from the body, meaning it does not accumulate over time.
Short-term exposure to MMA can cause irritation of the skin, eyes, and mucous membranes. Some individuals may develop allergic skin reactions. Respiratory symptoms such as:
Chest tightness
Coughing
Wheezing
Shortness of breath
may occur after inhalation.
Neurological symptoms have also been reported, including
In animals, high levels of inhalation exposure have led to damage in nasal passages and lungs, and oral exposure has caused liver damage. Overall, MMA has low to moderate acute toxicity by inhalation or ingestion in animal tests.
Workers exposed to MMA over long periods may experience:
One study also noted a possible link to cardiovascular disorders, though more evidence is needed.
In animal studies, chronic exposure to high concentrations resulted in:
The U.S. EPA Reference Concentration (RfC) is 0.7 mg/m³, based on respiratory effects in rats. The Reference Dose (RfD) is 1.4 mg/kg/day, based on no observed adverse effects in animal studies.
There are no comprehensive studies in humans. However, inhalation of high levels of MMA in rats led to:
MMA and its by-products can cross the placenta, reaching foetal tissues.
A retrospective study suggested a possible link to colon and rectal cancer in workers exposed to MMA. However, further analysis showed no strong causal relationship due to multiple confounding factors.
Animal studies involving inhalation and oral exposure showed no evidence of carcinogenicity. The EPA classifies methyl methacrylate as “not likely to be carcinogenic to humans.
Eye Contact:
If methyl methacrylate gets into the eyes, remove contact lenses if present. Rinse eyes immediately with running water for at least 15 minutes, keeping the eyelids open. Cold water can be used. Avoid using any eye ointments. Seek medical attention without delay.
Skin Contact:
Rinse the affected skin area thoroughly with plenty of water and a non-abrasive soap. Pay close attention to skin folds and crevices. Cold water may be used. Apply an emollient to soothe the irritated area. If irritation continues, seek medical help. Contaminated clothing should be washed before reuse.
Serious Skin Contact:
Clean the skin using a disinfectant soap, then apply an anti-bacterial cream. Get medical assistance immediately.
Inhalation:
Move the individual to a well-ventilated area and allow them to rest. Seek medical attention promptly.
Serious Inhalation:
Evacuate the person to a safe area as soon as possible. Loosen tight clothing such as collars, belts, or waistbands. If breathing is difficult, administer oxygen. If the person is not breathing, perform mouth-to-mouth resuscitation. Seek emergency medical help.
Ingestion:
Do not induce vomiting. Loosen tight clothing. If the person is not breathing, start mouth-to-mouth resuscitation. Get medical assistance immediately.
Methyl methacrylate is flammable, especially in the presence of open flames and sparks, and may be explosive when exposed to heat.
Use local exhaust ventilation or other engineering controls to maintain airborne concentrations of methyl methacrylate below the established threshold limit values. Ensure that eyewash stations and safety showers are located close to areas where the chemical is handled.
When handling methyl methacrylate, the following PPE is recommended:
In the event of a large spill, additional protection includes:
Note: These are general recommendations. Always consult a qualified safety specialist before working with methyl methacrylate to ensure proper protection for your specific environment.
