The combination of acetone (a highly effective solvent found in nail polish remover) and isopropyl alcohol (IPA, commonly known as rubbing alcohol and a disinfectant) is a frequent safety concern. Because both liquids are prevalent in homes and workplaces, understanding the safety implications of combining them is necessary. This article clarifies the physical and chemical hazards of this mixture and provides practical guidance on safe handling and storage.
The Immediate Safety Verdict
Acetone and isopropyl alcohol are miscible, meaning they blend completely into a single, stable solution without separating or reacting to form a new compound. This chemical stability means there is no immediate danger of a spontaneous explosion or the generation of extreme heat upon mixing. However, the resulting mixture is far from safe due to a significant increase in physical hazards. The combination creates a solution that is considerably more volatile and flammable than isopropyl alcohol alone, magnifying the risk of fire and inhalation exposure.
Understanding the Combined Chemical Hazard
The primary danger in combining these solvents comes from their enhanced physical characteristics, most notably their increased volatility. Volatility refers to how easily a substance turns into vapor at a given temperature, and both acetone and IPA are already highly volatile liquids. Acetone has a very low flash point, which is the lowest temperature at which a liquid produces enough vapor to form an ignitable mixture with air near its surface.
A mixture of acetone and isopropyl alcohol will have a lower flash point than pure isopropyl alcohol, making the entire solution more prone to ignition. For example, pure acetone’s flash point is approximately 0°F (-18°C), while IPA’s is 53°F (11.7°C). The combined liquid will give off flammable vapor much more readily and at lower temperatures than the rubbing alcohol on its own. The resulting vapor cloud is also denser than air, meaning it can travel along floors and low-lying areas to reach a distant ignition source, causing a dangerous flashback.
The enhanced volatility also directly increases the risk of inhalation toxicity. As more liquid turns into vapor, the concentration of fumes in the surrounding air rises rapidly. Breathing high concentrations of either acetone or IPA vapor can cause irritation to the nose, throat, and respiratory tract. High exposure can lead to central nervous system effects, with symptoms including headaches, dizziness, nausea, and drowsiness. The increased rate of evaporation from the mixture makes achieving these hazardous vapor concentrations in an enclosed space much easier and faster.
Safe Handling and Storage Protocols
Given the extreme flammability and inhalation risks, strict safety protocols must be followed when handling these solvents, whether separately or mixed. Working only in highly ventilated areas is paramount to prevent the accumulation of flammable and toxic vapors. If natural ventilation is inadequate, mechanical exhaust systems or a chemical fume hood should be used to disperse the fumes.
It is absolutely necessary to eliminate all potential ignition sources from the work area, including open flames, pilot lights, hot surfaces, and any equipment that can generate a spark. Because the vapors are heavier than air, this precaution extends to ground level and any nearby drains. Specialized personal protective equipment, such as vapor-resistant gloves and safety goggles, should be worn to protect the skin and eyes from irritation and absorption.
For storage, containers must be kept tightly sealed to minimize evaporation and vapor release. These flammable liquids should be stored in a cool, dry, and well-ventilated area, away from direct sunlight and any source of heat. Additionally, they must be segregated from incompatible chemicals, such as strong oxidizing agents or acids, to prevent accidental reactions. Waste liquid, including any mixed solution, should never be poured down a sink or drain; instead, it must be collected in a clearly labeled container for disposal by a licensed hazardous waste contractor in accordance with local regulations.