CAS RN: 111-65-9

Health Effects

    • A) USES: Hydrocarbons are a diverse group of organic compounds that are made up of primarily carbon and hydrogen atoms. Hydrocarbons are derived from petroleum, coal tar and natural gas, as well as from plants and animals. They may be classified as aliphatic (including the paraffins, olefins, acyclic terpenes, and acetylenes) and cyclic (including the alicyclics, aromatics and cyclic terpenes). Examples range from gasoline to essential oils to solvents. They are used as fuels and solvents, and are found in many household and commercial products.
    • B) PHARMACOLOGY: Pharmacology of hydrocarbons varies according to the specific substance. Some have sites of action in the CNS, namely increasing neurotransmitter binding and potentiating nicotinic blockade by interacting with acetylcholine receptors. Others stimulate GABA A activity. Glutamate release may be stimulated or transmission inhibited, depending on the specific agent. Glycine receptor activity may be augmented with certain hydrocarbons, and hydrocarbons are used as general anesthetics. In addition, alpha-2 adrenergic receptor activation can occur.
    • C) TOXICOLOGY: Hydrocarbons are a large and diverse group of substances with toxicity varying according to specific substance and route of exposure. Pneumonitis after aspiration is common and is the main route of injury from hydrocarbons. The exact mechanism of pulmonary toxicity is unclear but is likely due to direct toxicity to lung tissue as well as destruction of surfactant. Low viscosity, low surface tension and high volatility of a hydrocarbon (gasoline, for example, has all of these properties) increase the aspiration potential of that particular compound. Pulmonary toxicity can also occur after IV injection of hydrocarbons. Acute systemic toxicity is primarily due to CNS depression, reflecting the inhalational anesthetic effects of hydrocarbons. Inhalational abuse of hydrocarbons can cause simple asphyxiation. Chronic exposure in industrial settings or after long-term inhalational abuse can lead to chronic nervous system effects. Chlorinated hydrocarbons may cause cardiac sensitization to catecholamines, predisposing patients to cardiac dysrhythmias. Halogenated hydrocarbons may also cause hepatotoxicity, nephrotoxicity, and electrolyte disturbances. Hydrocarbons can destroy lipid bilayers and this can lead to "defatting" dermatitis following prolonged skin exposure. Capillary endothelium can be severely damaged in any organ system exposed to hydrocarbon. Hemolysis is rarely reported after hydrocarbon ingestion. Benzene is a bone marrow toxin.
    • D) EPIDEMIOLOGY: Poisoning is relatively common as these products are widely available in homes and industrial settings. Populations at highest risk include children with unintentional exposure (often ingesting pleasant-smelling oils), workers with occupational exposures, and those who intentionally abuse solvents via inhalation (often referred to as "sniffing" or "huffing"). Toxicity is primarily due to aspiration, but may occur via oral, parenteral, dermal or inhalational routes depending on the substance and nature of exposure.
      • 1) ACUTE EFFECTS OF INGESTION by SIMPLE PETROLEUM DISTILLATES: Low viscosity, highly volatile hydrocarbons (eg, kerosene, gasoline, liquid furniture polish) are chiefly aspiration hazards. Pulmonary damage, transient CNS depression or excitement, and secondary effects of hypoxia, infection, pneumatocele formation, and chronic lung dysfunction can occur. Cardiac complications are rare. These hydrocarbons are poorly absorbed from the gastrointestinal tract and do not cause appreciable systemic toxicity by this route unless aspiration has occurred.
      • 2) ACUTE EFFECTS OF INGESTION by CHLORINATED AND AROMATIC HYDROCARBONS: Many chlorinated, aromatic and other substituted hydrocarbons can produce systemic toxicity following ingestion. CNS, respiratory depression, dysrhythmias, gastrointestinal disturbances, and other effects may occur depending on the agent and amount ingested.
      • 3) ACUTE EFFECTS OF INHALATION: Cardiac dysrhythmias and CNS depression are major concerns of acute exposure. Straight chain hydrocarbons with few carbon atoms (eg, methane, ethane, propane gases) can cause asphyxiation if exposure occurs in poorly ventilated spaces.
        • a) INHALATIONAL ABUSE ("sniffing") of some hydrocarbons can result in sudden death, encephalopathy, residual neurological impairment, nephrotoxicity, hepatotoxicity, acid-base disturbances, and rhabdomyolysis.
      • 4) INJECTION of kerosene, naphtha, turpentine, gasoline, or hydrocarbon insecticides has resulted in febrile reactions, local tissue inflammation and systemic effects, including pulmonary edema, pneumonia, and mild CNS depression. Severe cases have resulted in multiorgan dysfunction syndrome. Injection of pressurized hydrocarbons has caused severe tissue damage.
      • 5) DERMAL/EYE: Mild to moderate eye irritation and reversible ocular injury may occur after contact with most hydrocarbons. Acute but prolonged exposure to some hydrocarbons can result in dermal burns and occasionally, systemic effects. Frostbite can result from contact with some liquefied gases (eg, propane, methane, ethane).
        • a) LOW VISCOSITY, UNSUBSTITUTED: Hydrocarbons with low viscosity (less than 100 S.U.S.), low surface tension, and high volatility are most likely to cause aspiration pneumonitis. Vapor inhalation can cause CNS depression or excitation and other effects. Examples: kerosene, mineral seal oil, gasoline, petroleum naphtha.
        • b) HIGH VISCOSITY, UNSUBSTITUTED ALIPHATIC: Hydrocarbons with high viscosity and low volatility are less likely to be aspirated after ingestion and are generally poorly absorbed from the gastrointestinal tract. Petroleum jelly may cause a mild laxative effect. Oil mist inhalation may cause lipoid pneumonia. Examples: motor oil, petroleum jelly.
        • c) TERPENES: In addition to aspiration, these tend to produce a mild CNS depression after ingestion. Examples: turpentine oil, pine oil. Pine oil cleaners may contain approximately 10% isopropyl alcohol and other additives which may contribute to the observed toxic effects.
        • d) AROMATICS: These have a high potential for CNS depression, a mild tendency to cause cardiac irritation, and little risk of aspiration. Adverse effects can result from vapor inhalation, ingestion, or skin exposure. Examples: benzene, xylene. Many polyaromatic hydrocarbons are potential carcinogens.
        • e) HALOGENATED-CHLORINATED: These can produce CNS effects, dysrhythmias, renal and hepatic effects. Aspiration is a small risk. Adverse effects can result from vapor inhalation, ingestion, or skin exposure. Examples: chloroform, carbon tetrachloride, trichloroethylene.
        • f) NOTE: Brominated hydrocarbons, fluorinated hydrocarbons, alcohols, esters, ethers, chlorinated hydrocarbon pesticides, and other hydrocarbons are covered in other managements.
      • 7) MILD TO MODERATE POISONING: The primary effect seen in mild to moderate inhalational poisoning is euphoria and intoxication followed by CNS depression. This should resolve quickly with removal from the source of inhalational exposure. Patients with oral exposure usually have some gastrointestinal upset and then can develop systemic symptoms as the hydrocarbon is absorbed if a large quantity is ingested. Patients who have vomiting are at increased risk of aspiration. Aspiration may cause minimal respiratory symptoms (eg, an intermittent cough) initially but progress to severe respiratory injury.
      • 8) SEVERE POISONING: Severe effects may include coma and dysrhythmias. Severe pneumonitis from aspiration may require prolonged intubation. Patients that aspirate will often display a systemic inflammatory response including fever. Chlorinated hydrocarbons can cause ventricular dysrhythmias, and can cause hepatic necrosis that may progress to liver failure. Injection can cause compartment syndrome and necrotizing fasciitis.
      • 9) CHRONIC POISONING: Long-term or repeated exposure to certain aromatic and chlorinated hydrocarbons can result in hematologic (eg, benzene), hepatotoxic (eg, chlorinated hydrocarbons), renal (eg, chlorinated hydrocarbons), neuropsychiatric (eg, toluene), neurological (eg, n-hexane) and carcinogenic (eg, benzene, vinyl chloride) effects. Some effects have occurred primarily in chronic solvent abusers or glue sniffers (eg, neuropsychiatric, renal, and hepatic effects of toluene). Chronic or repeated exposure can result in skin irritation due to defatting of the skin. Greases, coal pitch, and cutting oils can produce acne and folliculitis. Chlorinated aromatic hydrocarbon exposure can result in chloracne.
  • A) In a prospective study in Toronto, major congenital malformations were noted in 13 of 125 fetuses of mothers exposed to organic solvents during pregnancy. An analysis of data from the ongoing, case-control, National Birth Defects Prevention Study found that for women with occupational exposure to polycyclic aromatic hydrocarbons (PAH) in the month before through 3 months after conception had increased risk for having offspring with a neural tube defect (NTD), particularly spina bifida; however, after adjusting for confounders, the odds ratio for NTDs and spina bifida decreased and lost statistical significance.
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