Veil of Vapors: Unmasking the Hidden Perils of Hexane

Hexane, a hexyl hydride, is a chemical compound of six carbon atoms arranged straight. It has the chemical formula C6H14 and a molecular weight of 86.2. Hexane is a liquid that evaporates quickly at room temperature and has no color. It boils (turns into a gas) at 69°C and smells like gasoline. It doesn’t mix with water, and its vapors (gas form) are heavier than air, so they can move along the ground and catch fire if they come into contact with a spark or flame. Hexane can react with certain strong chemicals, leading to fire and explosions and damaging plastic, rubber, and coatings.

When people refer to “hexane,” they usually mean n-hexane, the straight-chain version. Research has shown that only n-hexane and mixtures containing it can damage nerves, while other forms of hexane do not have the same effect.

Why understanding hexane is crucial?

Understanding hexane is crucial for occupational safety and public health because it is a widely used industrial chemical that poses significant health risks when the users don’t follow safety measures properly. Hexane exposure can lead to acute and chronic health issues, including respiratory irritation, nerve damage, and brain disorders. Workers in industries that use hexane are at particular risk, and without knowledge of its dangers, workers may not take appropriate precautions, leading to serious health consequences. Ensuring workers and employers know hexane’s hazards helps implement necessary controls to prevent harm, such as ventilation, protective equipment, and exposure limits.

Relating Hexane Exposure to Everyday Situations

Household Products:
- Many people may not realize that hexane is present in everyday household products. For example, certain adhesives, paints, and cleaning agents contain hexane as a solvent. If you’ve ever used strong glue for DIY projects or certain types of paint, you might have been exposed to hexane vapors. Ensuring good ventilation and using protective gear like gloves and masks can help reduce the risk.
Automotive Work:
- If you work on cars or have ever been around a mechanic’s workshop, you might have encountered hexane. It’s a component of gasoline and is also used in degreasers and cleaners. Mechanics who regularly use these products in poorly ventilated areas could be at risk of chronic exposure, which might lead to health issues over time.
Food Processing:
- The food industry often uses hexane, particularly in the extraction of oils from seeds like soybeans. While most of the hexane is removed before the oil reaches consumers, workers involved in the extraction process may be exposed—this is why food processing plants have strict regulations and safety procedures to protect their employees.
Footwear and Furniture Manufacturing:
- Shoes, handbags, and furniture often use adhesives containing hexane. If workers don’t follow safety protocols in factories where they prepare these products, workers could be exposed to high levels of hexane—this has been a significant issue in places where industrial safety standards are not rigorously enforced.

Occupational Exposures

Hexane is found in various industrial products, such as solvents (chemicals that dissolve other substances), adhesives (glues), protective coatings, and paints. It’s also a part of gasoline and can be present during oil refining. In workplaces, n-hexane is rarely pure and is usually mixed with other chemicals. It is often found in products like petroleum ether, which is used to thin out adhesives and paints. Because hexane can be harmful, it’s frequently replaced with a similar but less toxic chemical called heptane.

Hexane mainly removes oils such as soybeans, peanuts, and corn from seeds and vegetables. It is also present in products like paints, lacquers (a type of protective coating), and inks and is used in making things like shoes, handbags, suitcases, and furniture. Workers in these industries—such as oil refineries, shoe factories, or labs, might be exposed to hexane, sometimes in high amounts.

Health Effects and Diagnosis

Hexane is a common air pollutant that can be absorbed into the body when inhaled (breathed in) or through the skin. Once inside, it spreads throughout the body, especially to fatty tissues like the brain, and is partly exhaled or removed through urine. The temporary buildup of hexane in the brain can cause effects similar to those caused by inhaling other chemicals or anesthetics (substances that make you lose feeling).

In the liver, hexane is changed into a harmful substance called 2,5-hexanedione. This substance can build up in the protective layer around nerves, leading to nerve damage, which can cause a loss of feeling and movement in the fingers and limbs.

Acute Diseases Caused by n-Hexane

Respiratory and Eye Irritation:
- Symptoms: High exposure to n-hexane can irritate the skin, eyes, and breathing passages. Respiratory symptoms include redness, itching of the throat, and coughing. Skin contact can cause blisters, redness, and pain, while eye exposure may damage the eye’s outer layer.
- Diagnosis: Breathing problems can appear several hours after exposure. Chest X-rays and lung function tests may show signs of irritation.
Narcotic Syndrome:
- Symptoms: Even though n-hexane isn’t highly toxic in small amounts, it can act as a mild anesthetic. High levels of exposure (over 1,000 parts per million, or ppm) can cause symptoms like euphoria (a feeling of extreme happiness), headache, nausea, dizziness, and drowsiness. Severe cases can lead to loss of consciousness or even a coma.
- Diagnosis: If someone inhales a large amount of n-hexane, they may develop narcotic syndrome, with symptoms starting from mild dizziness and happiness to severe weakness, confusion, and potentially a coma.

Chronic Diseases Caused by n-Hexane

Peripheral Polyneuropathy:
- Description: This condition affects the nerves in the lower limbs, causing numbness, muscle weakness, and loss of sensation. It usually occurs after prolonged exposure to hexane at levels between 250 and 2,500 ppm, especially in poorly ventilated workplaces.
- Diagnosis: Symptoms include numbness in the hands and feet, muscle weakness, and loss of tendon reflexes, starting with the Achilles reflex. Tests like electromyography can show nerve damage, and nerve biopsies may reveal demyelination (damage to the protective covering of nerves).
Chronic Toxic Encephalopathy:
- Description: Long-term exposure to organic solvents, including n-hexane, can lead to chronic toxic encephalopathy, also known as organic brain syndrome. This condition develops gradually, resulting in memory loss, difficulty concentrating, mood changes, and reduced cognitive function.
- Diagnosis: Symptoms progress through three stages: from mild depression and irritability to severe memory loss and impaired judgment. In advanced cases, the damage is irreversible, even after exposure stops.

Case Study 1: Footwear Factory Workers in China

In the early 2000s, a large number of workers in shoe manufacturing factories in China experienced severe neurological symptoms, including numbness, muscle weakness, and difficulty walking. Investigations revealed that these workers were exposed to high levels of n-hexane, used as a solvent for shoe assembly glues. Due to poor ventilation and lack of protective equipment, the workers inhaled significant amounts of hexane vapors over extended periods. Many were diagnosed with peripheral neuropathy, a condition that causes nerve damage. This incident led to stricter regulations and improved factory safety practices, including substituting less toxic solvents and better ventilation systems.

Case Study 2: Hexane Exposure in a Snack Food Processing Plant

A snack food processing plant in the United States used hexane to extract soybean oil. Workers faced exposure to hexane vapors due to inadequate ventilation and insufficient personal protective equipment. Several employees developed symptoms of dizziness, headaches, and respiratory irritation. One worker, with prolonged exposure, experienced chronic symptoms—including memory loss and concentration difficulties—which were later diagnosed as chronic toxic encephalopathy. The plant underwent a comprehensive safety overhaul, replacing hexane with a safer alternative and implementing strict exposure monitoring and protective measures.

Prevention

It’s essential to use less toxic alternatives like n-heptane whenever possible. If there is no alternative but to use hexane, ensure proper ventilation and exhaust systems are in place to control exposure. Workers should wear protective equipment like gloves, safety goggles, and respirators when necessary. Many countries have set exposure limits for hexane, with a common standard being 50 ppm as an 8-hour time-weighted average, which provides reasonable protection for workers’ health.

Call to Action: Protect Yourself and Your Workplace

Hexane exposure is a severe health risk that can lead to long-term damage if not properly managed. It’s crucial for everyone working in industries where hexane is present to take proactive steps to safeguard their health and well-being.

Here’s what you can do:

Check Your Workplace: Identify any products or processes that contain or use hexane. If hexane is present, ensure that all safety measures are in place.
Consult Safety Guidelines: Familiarize yourself with safety regulations and guidelines regarding hexane use. Scientists designed these guidelines to protect you from harmful exposure.
Get Trained: Proper handling of hazardous materials like hexane requires specific knowledge. Ensure training for you and your colleagues in the safe use of hexane, including how to use protective equipment and what to do in case of exposure.
Advocate for Safety: If you notice gaps in safety procedures or equipment in your workplace, speak up. Your and your coworkers’ health depends on a safe working environment.

Taking these actions protects you and contributes to a safer workplace for everyone. Don’t wait for an incident—act now to prevent hexane-related health issues and ensure a healthy, safe working environment.