WHAT IS POPCORN LUNG? UNDERSTANDING THIS SERIOUS RESPIRATORY CONDITION

Key Takeaways

• Popcorn lung (bronchiolitis obliterans) is a rare but serious condition that damages the small airways of the lungs and causes long-term breathing problems.

• It is most strongly linked to high, repeated exposure to certain chemicals, especially diacetyl used in industrial settings—not typical consumer vaping use.

• Modern regulated vape products have largely removed diacetyl, making the risk from legally compliant e-liquids extremely low compared to historical cases.

Popcorn lung, medically known as bronchiolitis obliterans, is a serious and irreversible respiratory condition that has gained significant attention in recent years. This devastating disease primarily affects the smallest airways in the lungs, called bronchioles, causing scarring and inflammation that can severely impact breathing capacity. Originally discovered in workers at microwave popcorn factories, popcorn lung has since been linked to various chemical exposures, including certain industrial chemicals.

Understanding popcorn lung is crucial for anyone exposed to potential risk factors, particularly those who vape or work in industries involving chemical exposure. While relatively rare, the permanent nature of this condition makes prevention and early recognition vital. This comprehensive guide explores everything you need to know about popcorn lung, from its causes and symptoms to prevention strategies and treatment options.

The Science Behind Bronchiolitis Obliterans Syndrome

Bronchiolitis obliterans occurs when the bronchioles, the tiniest air passages in your lungs—also known as tiny airways—become inflamed and subsequently scarred. These tiny airways end in tiny air sacs (alveoli), where oxygen exchange occurs. This scarring process, known as fibrosis, causes the airways to narrow or become completely blocked. Unlike larger airways that can compensate for damage, bronchioles are so small that even minor scarring can significantly impact lung function. Popcorn lung is a type of flavourings-related lung disease, often linked to chemical exposure from artificial flavourings like diacetyl.

The condition develops through a complex inflammatory process. When toxic chemicals irritate the delicate lining of the bronchioles, the body’s immune system responds by sending inflammatory cells to the area. While this response is meant to be protective, chronic exposure or severe acute exposure can lead to excessive inflammation and subsequent scarring. Popcorn lung causes damage and scarring in the tiny airways, but does not involve abnormal cell growth like cancer.

What makes popcorn lung particularly concerning is its progressive nature. Once the scarring begins, it tends to worsen over time, even after exposure to the causative agent has stopped. The scar tissue continues to build up, further restricting airflow and making breathing increasingly difficult. Popcorn lung is a non-cancerous lung disease caused by chemical exposure, while lung cancer involves uncontrolled cancer cell growth in the lungs.

How Popcorn Lung Affects Lung Function

Normal lung function allows for efficient oxygen exchange and easy breathing, but this is compromised in popcorn lung.

The respiratory system relies on a complex network of airways to deliver oxygen to the bloodstream and remove carbon dioxide. When bronchioles become scarred and narrowed, several problems occur:

• Reduced airflow makes it harder to breathe, especially during physical activity

• Air can become trapped in parts of the lung, leading to overinflation

• Gas exchange becomes less efficient, potentially affecting oxygen levels

• The work of breathing increases significantly, causing fatigue and shortness of breath

Primary Risk Factors That Cause Popcorn Lung

The most well-documented cause of popcorn lung is exposure to the chemical diacetyl, a flavouring agent that gives butter-flavoured foods their distinctive taste and aroma. The Centers for Disease Control and Prevention (CDC) has extensively studied chemical diacetyl exposure in workplace settings, particularly in food manufacturing facilities. (1)

Factory workers at microwave popcorn plants were at higher risk of developing popcorn lung due to repeated exposure to chemical diacetyl. Diacetyl was first identified as a cause of bronchiolitis obliterans in these workers in the early 2000s. These workers inhaled diacetyl vapours daily, leading to an outbreak of the condition that gave popcorn lung its common name. Diacetyl is a proven cause of popcorn lung and was used in some flavoured E-Cigarettes made outside the UK.

Other risk factors for developing popcorn lung include exposure to chemicals such as formaldehyde, ammonia, and metal oxides from welding, which can also cause this lung condition. Certain populations, such as factory workers and those exposed to these chemicals, are at higher risk of developing popcorn lung. Since then, diacetyl has been found in numerous other products and industries.

Common Sources of Diacetyl Exposure

• Food Manufacturing: Facilities producing flavoured foods, baked goods, and dairy products (2)

• Vaping Products: Some flavoured e-cigarettes and flavoured e-liquids contain diacetyl or related compounds
  Public Health England states that some flavourings used in e-liquids to provide a buttery flavour contain diacetyl, however diacetyl has been banned as an ingredient in UK-made e-liquids.

• Industrial Settings: Chemical plants and facilities using flavouring compounds

• Consumer Products: Certain flavoured foods and household items

Other chemicals that can cause similar lung damage include acetyl propionyl (also known as 2,3-pentanedione) and other α-dicarbonyl compounds. These chemicals are often used as diacetyl substitutes but can be equally harmful to lung tissue.

Vaping and Popcorn Lung Risk

The relationship between vaping and popcorn lung has been a subject of significant research and debate. Some early e-cigarette liquids contained diacetyl, particularly those with buttery or custard flavours. However, reputable manufacturers have since reformulated their products to exclude these harmful chemicals.

As of 2026, there are no confirmed cases of popcorn lung directly linked to the use of regulated E-Cigarettes. The American Lung Association has called popcorn lung a dangerous risk of flavoured e-cigarettes, highlighting the importance of understanding the health risks associated with vaping, however the volume of exposure to diacetyl from vaping is unlikely to match the high-volume exposure seen in popcorn factories where popcorn lung was first established, so claims that vaping causes popcorn lung are unfounded. (3) 

Vaping can involve inhaling harmful chemicals and ultrafine particles that can damage the lungs, and users should be aware of these potential health risks, though Public Health England maintain that E-Cigarettes are 95% less harmful than smoking tobacco cigarettes. (4)

At SMOKO E-Cigarettes and Vapes, our products are manufactured in the UK under strict quality controls and do not contain diacetyl or related harmful compounds. Our commitment to safety has helped protect our customers while they transition away from traditional cigarettes, contributing to preventing over 850 million cigarettes from being smoked over the past 12 years.

Recognising the Symptoms

Popcorn lung symptoms typically develop gradually and can be easily mistaken for other respiratory conditions. The most common early symptoms include (5):

• Persistent dry cough that doesn’t improve with time

• Shortness of breath, particularly during physical activity

• Wheezing or whistling sounds when breathing

• Chest tightness or discomfort

• Fatigue and reduced exercise tolerance

• Breathing issues

Symptoms of popcorn lung usually start slowly but keep getting worse, and may not appear until weeks after exposure to harmful chemicals.

As the condition progresses, symptoms may worsen and include:

• Severe shortness of breath even at rest

• Rapid breathing or feeling unable to catch your breath

• Significant reduction in physical activity tolerance

• Chronic fatigue and weakness

Unlike lung cancer, which often does not show symptoms in the early stages, popcorn lung symptoms generally worsen over weeks to months.

When to Seek Medical Attention

Anyone experiencing persistent respiratory symptoms, particularly if they have a history of exposure to diacetyl or work in high-risk industries, should seek medical evaluation promptly. Early diagnosis and intervention, while unable to reverse existing damage, can help prevent further deterioration and manage symptoms effectively. Early treatment can slow disease progression and improve patient outcomes.

Diagnosis and Medical Testing

Diagnosing popcorn lung requires a comprehensive medical evaluation combining clinical assessment, imaging studies, and lung function tests. The Mayo Clinic outlines several key diagnostic approaches used by healthcare professionals.

Pulmonary Function Tests

Lung function tests are crucial for diagnosing popcorn lung and assessing its severity. These tests measure how well your lungs work by evaluating:

• Forced expiratory volume (FEV1) - how much air you can exhale in one second

• Forced vital capacity (FVC) - total amount of air you can exhale

• Peak expiratory flow rate - how fast you can exhale

In popcorn lung, these measurements typically show an obstructive pattern, with reduced airflow rates that don't improve significantly with bronchodilator medications.

Imaging Studies

A chest X-ray is often performed as an initial imaging test for suspected popcorn lung, but it may appear normal in many cases and is not conclusive for diagnosing bronchiolitis obliterans. CT scans, particularly high-resolution computed tomography (HRCT), are more sensitive and are the preferred imaging modality for diagnosing popcorn lung, as they can better visualise lung abnormalities and assess the extent of airway obstruction.

High-resolution computed tomography (HRCT) scans of the chest can reveal characteristic changes associated with bronchiolitis obliterans. These may include:

• Mosaic attenuation patterns showing areas of different lung density

• Air trapping in certain lung regions

• Thickening of small airway walls

• Reduced blood vessel markings in affected areas

Additional Diagnostic Considerations

Healthcare providers will also conduct a thorough exposure history, looking for potential sources of diacetyl or other harmful chemicals. This includes occupational history, hobbies, and lifestyle factors that might contribute to chemical exposure. If imaging and lung function tests do not provide a clear diagnosis, a lung biopsy may be performed to confirm the presence of popcorn lung by providing definitive evidence of tissue damage.

Treatment Options and Management

Unfortunately, there is no cure for popcorn lung, and the damage to the airways is generally irreversible. However, various treatment approaches can help manage symptoms, slow disease progression, and improve quality of life.

Immediate Interventions

The first and most critical step in treating popcorn lung is eliminating further exposure to the causative agent. This may require:

• Changing jobs or work environments

• Discontinuing use of products containing harmful chemicals

• Using protective equipment in unavoidable exposure situations

• Implementing workplace safety measures

Medication Management

While medications cannot reverse lung damage, they can help manage symptoms and inflammation (6):

• Corticosteroids: Anti-inflammatory medications that may help reduce ongoing inflammation

• Bronchodilators: Medications that help open airways and improve breathing

• Immunosuppressive drugs: In some cases, medications that suppress immune system activity

• Oxygen therapy: Supplemental oxygen for those with severe breathing difficulties

Pulmonary Rehabilitation

Comprehensive pulmonary rehabilitation programs can significantly improve quality of life for people with popcorn lung. These programs typically include:

• Breathing exercises and techniques

• Physical conditioning and exercise training

• Education about the condition and self-management

• Nutritional counselling

• Psychological support and counselling

Prevention Strategies

Preventing popcorn lung focuses primarily on avoiding exposure to diacetyl and related chemicals. Preventing exposure to inhaled chemicals, such as diacetyl and other harmful substances, is essential for maintaining lung health. The Occupational Safety and Health Administration (OSHA) provides comprehensive guidelines for workplace safety and chemical exposure prevention. (7)

Workplace Safety Measures

For individuals working in high-risk industries:

• Use appropriate personal protective equipment, including respiratory protection

• Ensure proper ventilation in work areas

• Follow safety protocols for handling flavouring chemicals

• Participate in regular health screenings and lung function tests

• Report any respiratory symptoms promptly to healthcare providers

Consumer Awareness

For general consumers, prevention strategies include:

• Choosing vaping products from reputable manufacturers that test for harmful chemicals

• Reading ingredient labels on flavoured foods and products

• Being aware of potential chemical exposures in hobbies or home activities

• Maintaining good indoor air quality

The Role of Quality E-cigarette Products

For those who vape, selecting products from manufacturers with rigorous safety standards is essential. Quality E-Cigarette companies like SMOKO conduct comprehensive testing to ensure their products are free from diacetyl and other harmful compounds. Our UK-made products undergo strict quality control processes, helping our customers avoid potential respiratory risks while benefiting from a safer alternative to traditional cigarettes.

Living with Popcorn Lung

While popcorn lung is a serious condition, many people can maintain a reasonable quality of life with proper management and lifestyle adjustments. It is important to note that while both popcorn lung (bronchiolitis obliterans) and chronic obstructive pulmonary disease (COPD) are chronic respiratory conditions that affect breathing, they differ in their causes, progression, and management strategies. Bronchiolitis obliterans is rare in the general population but affects a significant percentage of lung transplant recipients. Key aspects of living with this condition include:

Lifestyle Modifications

• Avoiding respiratory irritants like smoke, strong chemicals, and air pollution

• Maintaining regular exercise within individual limitations

• Eating a healthy diet to support overall health and immune function

• Getting adequate rest and managing stress
  

Long-term Monitoring

Regular follow-up care is essential for managing popcorn lung effectively. This typically includes:

• Periodic lung function testing to monitor disease progression

• Regular chest imaging to assess lung changes

• Ongoing evaluation of symptoms and functional capacity

• Adjustment of medications as needed

Lung transplantation is a common setting where bronchiolitis obliterans develops, and popcorn lung can occur as a complication after lung or heart-lung transplants due to organ rejection. In rare cases, if lung damage from popcorn lung is extremely severe, a lung transplant may be needed.

The prognosis for popcorn lung varies significantly depending on the extent of exposure, individual factors, and how quickly the condition is diagnosed and managed. Some people experience stable symptoms with appropriate treatment, while others may see continued decline in lung function over time.

What is Popcorn Lung - Conclusion

Understanding what popcorn lung is and how to prevent it empowers individuals to make informed decisions about their health and safety. Whether in the workplace or making consumer choices, awareness of diacetyl exposure risks can help prevent this serious respiratory condition.

For those who choose to vape as an alternative to smoking, selecting products from reputable manufacturers committed to safety, like SMOKO E-Cigarettes and Vapes, provides an additional layer of protection while supporting the transition away from traditional cigarettes. If you are a smoker looking to quit, check out the SMOKO E-Cig & Vape Starter Kit Deals and make the switch today!

Frequently Asked Questions (FAQ)

What is popcorn lung?
Popcorn lung, medically known as bronchiolitis obliterans, is a rare condition that causes scarring and narrowing of the small airways in the lungs, leading to long-term breathing difficulties.

What causes popcorn lung?
It has been linked to prolonged, high-level exposure to certain chemicals, most notably diacetyl, which was once used in some food and industrial flavourings.

Can vaping cause popcorn lung?
There is currently no confirmed evidence linking regulated vaping products to popcorn lung. Most reputable manufacturers have removed diacetyl from e-liquids for many years.

What are the symptoms of popcorn lung?
Common symptoms include persistent coughing, wheezing, shortness of breath, and fatigue, which may worsen over time.

Is popcorn lung treatable?
There is no cure, but early diagnosis and treatment can help manage symptoms and slow progression.

References

(1) CDC: Diacetyl and Food Flavorings

(2) HSE: Exposure to diacetyl vapour in food and drink manufacture

(3) Cancer Research UK: Does vaping cause popcorn lung?

(4) E-cigarettes around 95% less harmful than tobacco estimates landmark review

(5) Popcorn Lung (Bronchiolitis Obliterans)

(6) How Bronchiolitis Obliterans Is Treated

(7) OSHA: DIACETYL

ABOUT THE AUTHOR

Written by Dan Overgage

Dan Overgage is a former smoker of 10 years until he became a client of SMOKO E-Cigarettes.  Dan started working with SMOKO 6 years ago after successfully quitting using our e-cigarettes and works across our Customer Service and heads up our content creation and research with a strong focus on all things quitting smoking.  During his tenure with SMOKO, Dan has written countless blogs and consults with countless clients every day to help them to stay smoke-free.

Last updated 23/01/2026