Plants and animals are not likely to store methyl isobutyl ketone. Effects of methyl isobutyl ketone on human health and the environment depend on how much MIBK is present and the length and frequency of exposure. Effects also depend on the health of a person or the condition of the environment when exposure occurs. Breathing MIBK for short periods of time, such as when painting in a poorly vented area, can adversely affect the nervous system. Effects range from headaches, dizziness, nausea, and numbness in fingers and toes to unconsciousness and death.
MIBK vapor irritates the eyes, the nose, and the throat.
Direct, prolonged contact with liquid methyl isobutyl ketone irritates the skin. MIBK liquid also irritates the eyes. These effects are not expected to occur at levels of MIBK that are normally found in the environment. Human health effects associated with breathing or otherwise consuming smaller amounts of MIBK over long periods of time are not known. Laboratory studies show that breathing large amounts of methyl isobutyl ketone during pregnancy causes adverse effects in the developing fetus of animals.