What condition of a package may indicate the presence of dry ice?

The presence of visible frost on the package is a clear indicator that dry ice is being used. Dry ice, which is solid carbon dioxide, sublimates at a temperature of -78.5 degrees Celsius (-109.3 degrees Fahrenheit). When it is exposed to warmer air, it produces a very cold vapor that can cause moisture in the air to freeze, leading to frost formation on the exterior of the package. This visible frost is a visual cue that helps handlers and anyone interacting with the package to recognize the potential risks associated with dry ice, including asphyxiation in poorly ventilated spaces and the need for proper handling due to its low temperature.

Other conditions, such as heavy weight, damaged packaging, and excessive heat, do not specifically indicate the presence of dry ice. Heavy weight could be attributed to various factors unrelated to the use of dry ice, and damaged packaging may signify a range of issues across different types of materials. Excessive heat is often a concern with hazardous materials, but it would not indicate the presence of dry ice, which is associated with very low temperatures. Therefore, visible frost is the most definitive indication of dry ice being present in a package.