Aerosol cans are sealed containers designed to dispense a product using a pressurized gas, making them highly sensitive to temperature fluctuations. The primary safety concern most people associate with aerosols is the risk of explosion from high heat, which causes the internal pressure to rise dangerously. While extreme cold drastically lowers this internal pressure, the risk of failure does not disappear entirely. Instead, cold temperatures introduce a different mechanism of failure that can still result in the can rupturing. This failure is a structural breach caused by the physical properties of the contents.
How Cold Affects Internal Pressure
The pressure inside an aerosol can is governed by the relationship between gas temperature and pressure. Aerosols use a liquefied gas propellant, such as hydrocarbons, which exists in a liquid and a gaseous state within the sealed can. As the temperature drops, the molecules of the propellant gas lose kinetic energy, causing them to move more slowly and exert less force against the can walls. This reduction in molecular activity directly causes the internal pressure to fall significantly.
A can pressurized to around 85 pounds per square inch (psi) at a comfortable room temperature of 70°F might see its pressure drop to as low as 45-50 psi at 32°F. This loss of internal force is the reason cold aerosols often produce a weak, sputtering, or inconsistent spray. The lower pressure cannot effectively drive the product through the valve system.
Structural Failure Due to Freezing
The primary risk of an aerosol can in extreme cold is not an explosion from high pressure, but a rupture caused by internal expansion. Many common aerosol products, including spray cleaners, foam insulation, and certain paints, contain water or water-based solvents. When the temperature falls below 32°F (0°C), this water content begins to freeze.
Water expands its volume by about nine percent when it transitions into ice, a powerful physical change that exerts immense stress. Since the can is a rigid, fixed-volume container, this expansion forces pressure outward against the weakest points of the metal structure. This stress often targets the can’s seams, the double-seals, or the valve assembly at the top. The result is a structural failure—the metal may crack, the seal may break, or the can may bulge and rupture.
In addition to the water content, the can’s metal material can become slightly more brittle at extremely low temperatures, further contributing to the risk of structural failure. The combined effect of material brittleness and the expansive force of ice is what causes the can to fail.
Safe Storage Temperatures and Recovery
Manufacturers typically recommend storing aerosol cans between 50°F and 120°F. Keeping the can above 50°F ensures the propellant remains energetic enough to function effectively, maintaining optimal performance. Exposure to temperatures below freezing, even for a short time, risks the freezing and expansion of water-based contents.
If an aerosol can has been exposed to freezing temperatures, it should never be placed near a direct heat source, such as a furnace or radiator. Rapid warming can cause thermal shock, which may stress the already compromised container. The safest method for recovery is to move the can to a room-temperature environment and allow it to thaw slowly and naturally over the course of several hours. If a can shows any visible signs of damage after thawing, such as bulging, rust, leaks, or a warped shape, it must be disposed of immediately. These deformities indicate the structural integrity has been compromised.