Is Methyl Ethyl Ketone safe when breathed in?

Inhalation of methyl ethyl ketone can cause irritation of the eyes, nose, throat, and respiratory tract.

Why here

Direct exposure to the respiratory system's mucous membranes.

What would have to be true

Human volunteer studies reported slight nose and throat irritation at 100 ppm (295 mg/m³) for 6 hours, becoming objectionable at 350 ppm (1032 mg/m³). Mild eye irritation was reported at 200 ppm (590 mg/m³) after 3-5 minutes.

Acute inhalation of high concentrations of methyl ethyl ketone can cause central nervous system depression, leading to symptoms such as headache, dizziness, fatigue, nausea, drowsiness, confusion, and in severe cases, unconsciousness.

Why here

MEK is absorbed through the lungs and affects the central nervous system.

What would have to be true

Symptoms like headache, dizziness, fatigue, and feeling of intoxication are reported in humans following inhalation. Severe CNS depression (e.g., unconsciousness) occurs at very high concentrations (several thousand ppm).

Prolonged or high-level inhalation exposure to methyl ethyl ketone may lead to systemic toxicity, including potential effects on the liver and kidneys, and metabolic disturbances such as hyperglycemia, ketosis, and metabolic acidosis.

Why here

MEK is absorbed through the lungs and distributed systemically, where it is metabolized and can affect various organs.

What would have to be true

Animal studies showed liver and kidney congestion, increased organ weight, and mild renal necrosis at very high concentrations (6,000 to 10,000 ppm). Human systemic toxicity symptoms like gastrointestinal upset, tremor, incoordination, and respiratory depression have been noted following inhalation.

Inhalation exposure to high concentrations of methyl ethyl ketone has been associated with developmental effects in animal studies, including reduced fetal body weight and bone abnormalities.

Why here

Inhaled MEK can be absorbed into the bloodstream and potentially cross the placental barrier to affect fetal development.

What would have to be true

Animal studies in rats showed fetotoxicity at 3,000 to 4,000 ppm (8,850 to 11,800 mg/m³) and reduced fetal body weight and bone abnormalities at 3,000 ppm.

Inhalation of methyl ethyl ketone vapor can irritate the eyes, nose, and throat.

Why here

Methyl ethyl ketone is a common volatile organic compound found in indoor air due to its use in consumer products like paints, varnishes, and cleaning solutions.

What would have to be true

Inhalation of methyl ethyl ketone vapor at concentrations as low as 100 ppm (295 mg/m³) for nose and throat irritation, and 200 ppm (590 mg/m³) for eye irritation.

Methyl ethyl ketone is a volatile organic compound (VOC) that readily evaporates into indoor air, contributing to indoor air pollution.

Why here

Methyl ethyl ketone is used in various consumer products such as varnishes, glues, and cleaning solutions, and its evaporation from these products releases it into indoor environments.

What would have to be true

Presence of methyl ethyl ketone in indoor air from consumer product use, with short-term indoor concentrations potentially elevated above levels considered safe for workers, especially in poorly ventilated areas.