CLINICAL PEARLS Hydrocarbon ingestion can cause severe aspiration pneumonitis, even in the absence of vomiting Even asymptomatic patients should have a chest radiograph obtained hours after ingestion to determine the need for further observation Current Evidence Hydrocarbons are carbon compounds that become liquid at room temperature The term hydrocarbon is somewhat confusing and is often used interchangeably with the term petroleum distillates However, whereas all petroleum distillates are hydrocarbons, not all hydrocarbons are petroleum distillates (e.g., pine oil) Hydrocarbons can be found in solvents, fuels, household cleaners, and polishes Hydrocarbons are typically divided into three categories: the aliphatic hydrocarbons, the aromatics, and the “toxic” hydrocarbons The aliphatic hydrocarbons are petroleum distillates and are found in such household products as furniture polish, lamp oils, and lighter fluids The aromatic hydrocarbons are cyclic structures and include toluene, xylene, and benzene These agents are found in solvents, glues, nail polish, paints, and paint removers The “toxic” hydrocarbons consist of a broad class of substances that possesses no specific profile of toxicity These agents include halogenated hydrocarbons and hydrocarbons that serve as vehicles for toxic substances such as pesticides The major toxicity of hydrocarbons varies from class to class However, they all have in common low viscosity and surface tension that permits them to spread freely over large surface areas This property (plus their solvent actions) leads to a necrotizing, potentially fatal chemical pneumonitis ( Fig 102.9 ) when these compounds are aspirated The high volatility of these substances is responsible for alterations in mental status, including narcosis, inebriation, and coma In addition to these toxicities, the solvents possess additional toxicities (see “Inhalants” section), including the risk of bone marrow injury (in the case of benzene) Finally, with the toxic hydrocarbons, additional toxicities may occur as a result of actions such as cardiotoxicity or as a result of the pharmacologic properties of the other agents contained within these compounds The major toxicity of hydrocarbons is classified in Table 102.15 The amount of ingested hydrocarbon is often difficult to quantify However, generally any degree of aspiration results in signs, including coughing, gagging, or tachypnea Less than mL of some compounds, when aspirated directly into