Flammable petroleum liquids emit what color smoke?

Flammable petroleum liquids typically emit black smoke when they burn. This black smoke is a result of the incomplete combustion of hydrocarbons present in the petroleum. The carbon particles produced during this combustion process give the smoke its dark appearance. Black smoke is an indicator of a fuel-rich environment, which is common with petroleum products because they often contain a significant amount of carbon.

In contrast, other colors of smoke are associated with different types of materials or combustion conditions. For instance, white smoke generally indicates the presence of water vapor or the burning of materials with a high moisture content, while gray smoke can signify a mixture of combustion materials, and yellow-green smoke is often associated with burning chemicals or specific types of plastics. Thus, the characteristic black smoke from flammable petroleum liquids is a distinct identifier of their combustion behavior.