Microwave popcorns contain a flavouring agent called diacetyl which causes obstructive lung disease.Manufacturers use trans fat because it has a distinct flavour, is solid at room temperature and is very cheap. Trans fat is the unhealthiest type of fat, increases bad cholesterol and risk of heart disease.Bags of Microwave popcorn are lined with chemicals called fluorocarbons which are carcinogenic, increase the risk of prostate and pancreatic cancer, and also disturb hormonal function, lower sperm counts and impair thyroid functioning.
The buttery flavour in popcorn comes from Diacetyl which, when burnt, can be damaging for lungs. This condition is sometimes termed as the popcorn lung disease.
Microwave popcorn has been associated with lung diseases as well. Diacetyl is a flavouring agent which is added to microwave popcorn.
There have been studies which indicate that an acid extracted from PFOA can cause cancer in animals, and might even cause cancer in humans.