Is it buttered popcorn lung or just the boring unbuttered kind?
The name probably comes from when researchers first identified the disease among workers in a microwave popcorn factory. The workers had breathed in diacetyl, a flavoring chemical used to make the popcorn taste buttery.
https://my.clevelandclinic.org/health/diseases/22590-popcorn-lung-bronchiolitis-obliterans