What does a higher vapor density typically indicate regarding a substance?

A higher vapor density indicates that a substance's vapor is heavier than air, and as a result, it is more likely to accumulate or settle closer to the ground. This characteristic is crucial in fire investigations, as heavier vapors can pose significant safety risks. For instance, flammable vapors that settle low to the ground can create hazardous conditions in enclosed spaces, increasing the risk of ignition sources leading to fires or explosions.

When evaluating other options, a higher vapor density does not inherently mean that a substance is more volatile or flammable, even though it may potentially indicate some degree of flammability when combined with additional factors, such as its specific chemical properties and the presence of ignition sources. Additionally, having a higher boiling point is not directly related to vapor density—substances can have high vapor densities while also having low volatility. Hence, understanding the implications of vapor density is key for safety and proper investigative procedures in fire and explosion assessments.