Vapors of flavoring ingredient, diacetyl harm

Factory workers in microwave popcorn factories have long been exposed to a dangerous but rare lung disease dubbed ‘popcorn lung.’ Now, the first-known case of a consumer who has contracted popcorn lung has turned up.

A man who consumed two bags of popcorn daily had problems with his breathing. His doctor, who is a researcher on popcorn lung, suspected he had contracted the disease when he began describing the symptoms he had been suffering.

The doctor had researched the disease before in a factory setting and was familiar with the symptoms. But she had never heard of a consumer connection before. In popcorn lung the bronchial tubes, which are very small airways in the lungs, are blocked by inflammation and scar tissue and the patient has difficulty blowing air out. In medicine, the condition is known as bronchiolitis obliterans -- literally, obliteration of the bronchials.

Popcorn lung has long been detected in popcorn factory workers who inhale a lot of fumes from a chemical called diacetyl. This is a natural substance that is used as a flavoring ingredient. In the factory, it is heated to give microwave popcorn its buttery taste. Some factory workers have died from popcorn lung, while others have needed lung transplants in order to be able to breathe and survive.

The doctor decided to send an industrial hygienist to check conditions at Watson’s house. The hygienist found that in the patient’s home, the levels of a flavoring ingredient called diacetyl were similar to that in microwave popcorn manufacturing plants. Because Watson was such a fanatic for popcorn, he was heating a lot of it in the microwave before eating it.

The popcorn industry has already acted on the issue. Manufacturers have announced they would eliminate the flavoring ingredient, diacetyl, from their product. They also pointed out that excessive amounts of diacetyl were involved in the known cases of popcorn lung.

Eating foods that contain diacetyl does not appear to be dangerous. However, breathing fumes that have diacetyl in them does appear to be hazardous, as what happened to microwave popcorn factory workers.

Note that microwave popcorn will emit hot fumes when you open the bag before the cooked contents have cooled down. The man was reported to have the habit of inhaling the aroma of microwave popcorn that had just been popped and before it had cooled. His doctor reports that his symptoms did not get worse when he was ordered to stop making microwave popcorn.

It may also be time for federal agencies to act. Some physicians have already urged the FDA to stop giving diacetyl the designation of a food ‘generally recognized as safe’.