Petroleum is toxic. In its crude and refined forms, it contains a mixture of hazardous chemicals that can damage the lungs, brain, liver, skin, and blood cells. The degree of harm depends on the type of petroleum product, how you’re exposed (breathing it, swallowing it, or getting it on your skin), and how long the exposure lasts. Even brief contact with certain petroleum products can cause serious injury, while long-term exposure is linked to cancer, organ damage, and immune suppression.
What Makes Petroleum Toxic
Petroleum isn’t a single chemical. It’s a complex mixture of hydrocarbons, and several of them are independently dangerous. The most concerning include benzene, toluene, xylenes, naphthalene, and hexane. Benzene is a known human carcinogen. Toluene and xylenes affect the nervous system. These compounds appear across a wide range of petroleum products, from crude oil to gasoline to jet fuel to mineral oils.
The hydrocarbons in petroleum are lipophilic, meaning they dissolve easily into fats. This property is exactly what makes them harmful. They can penetrate cell membranes, disrupting the structure that holds cells together and altering how cells communicate with each other. In the brain, this disruption interferes with the chemical signaling between neurons. In the lungs, it triggers inflammation, swelling, and bleeding in the tissue.
What Happens When You Inhale Petroleum Vapors
Inhaling petroleum fumes is the most common route of harmful exposure. The hydrocarbons in petroleum vapor can reach the brain through two paths: directly through the nasal passages via the olfactory system, or by entering the bloodstream through the lungs and circulating to the brain. Once there, they accumulate in the fatty tissue of nerve cell membranes and disrupt normal neurotransmitter signaling. This imbalance in brain chemistry is what produces the dizziness, headaches, nausea, and confusion that people report after inhaling petroleum fumes.
Short-term inhalation at high concentrations can cause stupor, loss of consciousness, and in extreme cases, death. This is a particular risk for adolescents who intentionally inhale petroleum products for intoxication, a practice sometimes called “huffing.” Even at lower concentrations, repeated inhalation over time causes measurable neurological harm.
The Danger of Swallowing Petroleum
Swallowing petroleum products is dangerous, but not primarily for the reason most people assume. The biggest risk isn’t what happens in your stomach. It’s what happens in your lungs. Liquid hydrocarbons are thin and slippery, and when swallowed, some almost inevitably slips past the windpipe and into the airways. This is called aspiration, and it happens easily during accidental ingestion, like when someone tries to siphon gasoline with a hose and their mouth.
Once petroleum reaches the lungs, it causes rapid inflammation, swelling, and bleeding in the lung tissue. Symptoms include coughing, wheezing, shortness of breath, fever, and blue discoloration of the lips and fingernails from lack of oxygen. Highly toxic hydrocarbons can cause respiratory failure quickly. In severe cases, a person may need a ventilator.
Critically, if someone swallows a petroleum product, vomiting should not be induced. This is a firm point of medical consensus. Vomiting forces the liquid back up through the throat, giving it a second opportunity to enter the lungs and making aspiration far more likely.
Skin Contact and Petroleum
Petroleum products strip natural oils from the skin. A single exposure typically causes mild irritation, but repeated or prolonged contact leads to drying, cracking, and dermatitis. This is well documented in occupational settings where workers handle petroleum distillates regularly. The skin damage itself isn’t usually life-threatening, but cracked skin opens a pathway for infection and allows deeper absorption of chemicals.
Interestingly, NIOSH notes that no chronic systemic effects have been reported from the widespread industrial use of petroleum distillates like naphtha, at least through skin contact alone. The greater systemic risks come from inhalation and ingestion.
Long-Term Health Effects of Chronic Exposure
The long-term picture is where petroleum toxicity becomes especially concerning. Studies of oil refinery workers, cleanup crews, and people living near spill sites have documented a range of chronic health problems that can persist for years after exposure ends.
Cancer is the most studied long-term risk. Workers with historical crude oil exposure show elevated rates of acute myelogenous leukemia and multiple myeloma. Benzene, one of petroleum’s key components, is the primary driver of these blood cancers. Beyond cancer, chronic exposure is linked to broader blood abnormalities including anemia, changes in white blood cell counts, and atrophy of the lymph nodes and spleen.
The liver takes significant damage from prolonged petroleum exposure. Ultrasound assessments of oil workers have revealed fatty liver disease and enlarged livers. Among volunteers who participated in the Deepwater Horizon oil spill cleanup, liver enzyme levels were elevated during the response and remained elevated in follow-up testing conducted seven years later. That persistence suggests ongoing liver stress long after the exposure itself ended.
Cardiovascular effects are also documented. Upstream oil workers show higher rates of cardiovascular disease, and studies of oil shale workers have found elevated rates of hypertension. Workers who cleaned up the 2002 Prestige oil spill off the coast of Spain still showed reduced lung function, chromosome damage, and genetic alterations years after the work was completed. Immune suppression, characterized by drops in key antibody levels, has been found in workers who maintain oil tanks on ships.
Petroleum Jelly: A Special Case
If petroleum is toxic, why is petroleum jelly sold as a skin care product? The answer comes down to purification. When petroleum jelly (petrolatum) is properly refined, the hazardous compounds are removed, and the remaining product has no known health concerns. The European Union requires that any petrolatum used in cosmetics must have a complete refining history proving it is non-carcinogenic.
The United States has no such requirement. Petrolatum sold in US personal care products is often not fully refined, which means it can contain residual polycyclic aromatic hydrocarbons (PAHs), a class of chemicals linked to cancer. There is no way for a consumer to verify proper refinement unless the manufacturer provides a complete refining history. Looking for “white petrolatum” or “USP grade” on the label offers some reassurance, as these designations indicate a higher standard of refinement.
How Exposure Levels Are Regulated
Workplace exposure to petroleum distillates is regulated by two federal agencies. NIOSH recommends a time-weighted average exposure limit of 350 mg/m³ over a work shift, with a ceiling of 1,800 mg/m³ for any 15-minute period. OSHA’s enforceable limit is higher, at 500 parts per million (2,000 mg/m³) as a time-weighted average. These limits apply to airborne concentrations in occupational settings and are designed to prevent the kind of chronic exposure that leads to organ damage and cancer.
For context, you can often smell petroleum products at concentrations well below these thresholds. If you can smell gasoline or another petroleum product strongly in an enclosed space, you’re being exposed to hydrocarbons, and ventilation matters. People working in garages, around fuel storage, or with solvents should treat petroleum vapors with the same caution they’d give any other toxic chemical.